Installing OpenCPN

Windows XP SP3/Vista/7

• Download the installation package for Windows from opencpn.org/download.
• Use the stable release for navigation en route, or if you just started using OpenCPN.
• Exit all other programs, including your anti virus program - known to create problems in some cases. Unplug your network cable, to be on the safe side.
• Run the downloaded installer. Re-start your anti-virus. Re-connect the network
• If upgrading from a previous version of OpenCPN, there is no need to un-install the old version. Simply install the new version and it will upgrade OpenCPN, saving all your existing configuration and preferences.
• If this is a new installation, click on the Toolbox icon  and configure your GPS source, chart directories, and other settings.
• If your installation goes well, but OpenCPN don't start as expected, try to download and install these runtime components.

Win 98/ME is supported up to version 2.1.0 From 2.3.0, Windows 98 and Windows ME are no longer supported.
Win 2000 is supported up to version 2.5.0.
Win XP SP 2 or 1 is supported up to version 2.5.0. The support was dropped with beta 2.6.1624.

Old versions of OpenCPN are available on SourceForge.

Linux

32/64 bit Ubuntu/Debian Distributions

32 bit Fedora / Cent OS

• Install a version of libwxgtk2.8-0 that is compiled with support for sdl - Simple DirectMedia Layer. Such versions are available from http://apt.wxwidgets.org.
  Download the correct package for your version of Debian or Ubuntu and
  
  $sudo dpkg -i ibwxgtk2.8XXXXXX (the proper name of the downloaded version)
  
  or, follow these instructions: wiki.wxpython.org/InstallingOnUbuntuOrDebian, to add apt.wxwidgets.org as a source for packages.
• It is recommended that you install the "xcalib" program, that is necessary to dim the screen for night time usage. Use your favorite package manager or just issue $sudo apt-get install xcalib from the command line.
• On Ubuntu, start "System->Administration->Synaptic". In Synaptic  go to "Settings->Repositories" and tick the box "Community-maintained Open Source software (universe)". Close Synaptic.
• Download the correct .deb or .rpm from opencpn.org/download.
• Use the stable release for navigation en route, or if you just started using OpenCPN.
• Click on the downloaded package. An installation manager will guide you on most Linux distributions. All dependencies should automatically be installed. If you have problems with dependencies, run the recommended command line in the next paragraph.
• sudo gdebi <downloaded_opencpn_file.deb>. The command "gdebi" will automatically install the dependencies for you.
• It is also possible to install the package via dpkg or rpm, on the condition that all dependencies are met.To make sure that this is the case on Ubuntu, open a terminal window to get a command line, (Applications->Accessories->Terminal) and copy and paste the following line: sudo apt-get install libwxgtk2.8-0  libwxbase2.8-0 wx-common  libglu1-mesa libgl1-mesa-glx zlib1g bzip2 gpsd gpsd-clients. Then proceed with the commands below
  

  • For Ubuntu: $ sudo dpkg -i <downloaded_file.deb> 
    For Fedora: # sudo yum install --nogpgcheck <downloaded_file.rpm>

  • The binary will be installed to /usr/local/bin/opencpn and the static data used by the program will be in /usr/local/share/opencpn 
    
• If this is a new installation, click on the Toolbox icon  and configure your GPS source, chart directories, and other settings.

Other 32 and 64bit Linux Distributions and the BSD operating systems.

• Currently other distributions requires compiling the source. This will involve resolving various dependencies and is for folks comfortable with developing on Linux.
• Download the source from sourceforge.net or directly from the Git server. The SourceForge link for this project is sourceforge.net/projects/opencpn/. More about compiling on Linux here.
• Interested in maintaining a package for your favorite Linux distribution? Follow the SourceForge link above.
• This also includes the different BSD distributions. Report your experiences back to the forum.

 

Mac OSX

• Work is underway to bring Mac up to speed with the other major operating systems. Check the download page for the latest available package.

Different versions of OpenCPN

• Use a "stable", official release for actual navigation. The latest stable release is always available at the top of the download page or from Source Forge.
• Beta releases are snapshots of the development process, and may contain errors or temporarily be unstable. Show stoppers are normally fixed very quickly however. This is where the latest features first are seen. Most of the time the beta releases are quite stable and the OpenCPN team appreciate it if more experienced users test the releases and report back. The place to report bugs and suggest features is the Tracker. To reach the Tracker from the OpenCPN Web pages click on the "Tracker" tab at the upper right (above the blue bar).
• To see what version you are using either look in  ?->about or at the top of your display. A lot of information is also available in the log file. See below.
  
  

Location of Important Files. Log and config files.

•  It is important to know the location of the log file and the configuration file, opencpn.conf(Linux) or opencpn.ini (Windows), on your computer. If you ask questions on the forum, there is a fair chance that you will be asked about the content in these files. Once you get familiar with OpenCPN, have a look at the files!
• Through out this documentation there will be many references to the configuration file, as it often is possible to change the default settings. This is an advanced subject once you are familiar with OpenCPN. All editing in the config files must be done with a text-editor, such as "notepad" in Windows.
• The configuration file is where all data, that needs to be persistent between sessions, are stored. The logfile keeps tab of what's going on in the current session.                          
• To find the locations of the files go to the ToolBar click on "About OpenCPN", the button furthest to the right. Look at the bottom  of the "About" Tab, highlighted below. The illustration below is from a Win XP. A quick way to view the logfile is to copy the full file path and then paste this into the address field in a web browser.
  
  
• On Linux the "opencpn.log" is in your home directory.
  The "opencpn.conf" is in a hidden directory, called "opencpn", also in your home directory.
  For a quick way to view the files you can try these commands.
  $gedit `echo $HOME/opencpn.log`
  $gedit `echo $HOME/.opencpn/opencpn.conf`
  Of course you can swap "gedit" for your favorite editor.
• On Windows 2000, XP and Vista and Windows 7 the two files are more difficult to find, so use the "About" dialog as described above.  Note that some folders in the path to the log and ini files may be hidden. Change the global folder and file settings to make hidden and system files visible, also change settings so that all file extensions are shown.

If something goes wrong

• If you have installed OpenCPN successfully and later run into trouble there is generally no point in reinstalling. It is a very common reaction among users, but achieves very little.
• First check your logfile and try to find a hint there.
• Next step would be to rename the configuration file - opencpn.ini. Close the application first though. When you start OpenCPN again it will be like a new install, no chart directories and all settings are default.
• If this is successful, please post your old config file, together with full information of what happened and your system, on the Cruisers Forum. To do this, first rename the file by adding ".doc" to the end of the file name.
• This will help the OpenCPN developers  to understand what's going on.

OpenGL

What is OpenGL an Overview
OpenGL is an open standard, cross platform, advanced graphic library. It uses the graphic cards processor (GPU) and memory to speed up applications. With OpenCPN the user with a typical modern graphic card will have an enhanced experience. Much faster and smoother zooming and panning as well as clearer and sharper chart rendering.

In OpenCPN OpenGL is a choice, the old graphic engine is still there. OpenGL will not work for everyone. Performance may not be improved with embedded graphics chips, often found in older laptops and netbooks.

Microsoft has gone from support to hostility towards OpenGL. There is currently a lot of trouble with OpenGL on Vista and W7 for all OpenGL applications, not just OpenCPN.

For Linux the situation is slightly different. Linux supports OpenGL, as it generally tends to support open standards. The user is however dependent on drivers from the graphic cards makers, and their support for OpenGL. This may change with projects like nouveau, a free driver for nVidias cards.

       
Without OpenGL                         With OpenGL
Heavy over zooming reveals some of the secrets behind OpenGL
 
Why introduce OpenGL in OpenCPN?
The main reasons are:

• Better performance, leveraging modern PC graphics cards that are ubiquitous and powerful.
• Better "eye candy", such as smooth zoom and pan, with little impact on responsiveness.
• Future cross-platform support (e.g Android/IOS)

Is OpenGL a good choice for everyone?
OpenCPNs performance with OpenGL is highly dependent upon your graphics hardware and drivers.

• Some graphics chip sets (e.g.intel 945G) have rather poor OpenGL driver support, so that we cannot fully utilize the hardware acceleration potential of these systems.
• nVidia graphics, even very old cards, seem to perform very well.
• Performance may not be improved with embedded graphics chips as often found in older laptops and netbooks.
• There is a lot of trouble with OpenGL on Vista and W7. Microsoft implemented a new screen compositing model for Vista and later, which "broke" many OpenGL apps
• Conclusion:Using OpenGL with OpenCPN will be a significant upgrade for some users of OpenCPN, but OpenGL may not be "better" for everyone's OCPN application.
• So, user's choice. If OpenGL works better for you, then use it. If not, the old DC based graphics render system is still in place, with performance equivalent to Version 2.5.0.

Start using OpenGL

• Find the latest driver for your graphic card. The driver that came with your operating system is not likely to be the best. Start looking at your graphic card makers home page.
• Go to the ToolBox->Settings and tick the two boxes "Use OpenGL" and "Enable Smooth Panning/Zooming".

Other tricks
If you have a lot of graphic memory, or very little, try to add the following to your config file:
"GPUMemorySize=nnn"
where nnn is graphics card memory size, in MBytes.
256 MBytes is the default.

Portable OpenCPN

The OpenCPN portable option allows the program to run fron an USB stick or run independent and parallell to a normal installation.
To differ between various instances of the program, the titlebar on portable versions looks like this.

It is thus possible to run multiple portable instances and identify each version.

To create a portable Windows version

The following files/directories/folders must be in the directory containing the OpenCPN executable:

1. OpenCPN.exe (of course)
2. "opencpn portable.bat" (or other name of user choice)
A MSDOS batch file containing the one line:
"opencpn -p"
3. msvcr100.dll
4. msvcp100.dll
5. Seven wxWidgets dlls
6. OCPN data directories
plugins/
s57data/
share/
sounds/
tcdata/
wvsdata/
doc/
7. license.txt

To run OpenCPN portably within this directory, simply execute the "opencpn portable" batch file. There may be a way to build a clickable shortcut to OpenCPN, with the -p option specified in the shortcut. But I could not figure it out. Windows insists upon a drive letter in the command line of the shortcut, which would defeat the whole purpose of portability.
Thus, the batch file....
I find that this works pretty well from a USB stick...

A Linux version

On linux, a similar functionality exists.
Copy the opencpn executable binary and the data directories mentioned above to a local directory.
In that directory, do
$ ./opencpn -p
This will cause all user data files to be created and used from within that local directory.
This can be useful for side-by-side testing...

Installing Charts

• If all is just black, with maybe some blue lines, you are viewing the background world vector shoreline chart. You must move to the geographical position of the charts you just loaded. As you come close you will see the outlines of your loaded charts, in red for raster charts and in green for S57 vector charts. Click in the rectangle created by the outlines, to activate, and view the chart.
• If you ticked the "Show Chart Outlines" box under the "Settings" tab the loaded charts will be outlined in red for raster and green for vector charts. In CM93 the charts will be outlined in purple. The smallest scale charts in CM93, the Z scale and A scale charts, will not be outlined. Neither will all available charts be visible as outlines at the same time. The reason for this is computing speed and clarity. Generally the next level or two of larger scale charts are shown. When large scale plans are available directly from A scale charts, with no intermediate charts, the outline of the larger scale charts will be visible from a zoom level between 1.5 and 2.0. Generally in areas where only A or Z scale charts are available, expect potentially dangerous omissions. Warning, do not use CM93 small scale charts alone for navigation without referring to other sources.
• Be aware that it is possible to "Over-zoom" charts in OpenCPN. A warning will appear on the display. Please respect that warning. It is recommended to not zoom more than a factor 2, for safe navigation. The actual zoom-factor appears in the lower right-hand corner of the display.
• It is safe and reasonably efficient to put all your charts except the CM93 database in one large directory, and set that directory in Toolbox->Charts. The CM93 database contains its own file and directory structure. The top-level directory only, of this database should be loaded, as described above, into OpenCPN.
  If you do a lot of chart downloads, updates, etc., then it will be faster to break the charts folder into smaller groups, and specify them individually in the Toolbox->Charts dialog. Consider using Chart Groups as well.
• "Scan Charts and Update Database " Use this option if you have made any changes to the contents of your chart directories, as for example after downloading new charts from NOAA, etc. It need not be checked if directories are added or subtracted, as the entire database will be scanned and updated automatically in this case.
• "Force Full Database Rebuild" is mainly aimed at users converting or correcting existing charts, in a situation where changes are made to the geo-referencing, outline of the chart, or other attributes in the kap file header section.
• OpenCPN,  supports  Mercator Charts, Transverse Mercator Charts, Universal Transverse Mercator (UTM) Charts and Polyconical Charts (used in parts of US and Canada). Charts using other projections will be displayed as if they were Mercator charts, but they will not be used for quilting.  Most charts are using one of the "Mercator" projections, so this limitation is not too bad.
  Other projections, such as Gnomonic, are mainly used in older, larger scale BA charts, for smaller areas, for example harbor plans, in scales larger than 1:50,000.
  The errors introduced in OpenCPN by treating these charts as Mercator are generally small, but be aware of this limitation.

Setting Up GPS

Windows 98/ME/2000/XP/Vista/7

To use OpenCPN with a GPS, a GPS receiver is needed.

There are a variety of possible choices for a GPS receiver:

• A computer, such as a Sony Vaio P has a built in GPS receiver
• A NMEA Expander to amplify a nmea stream to multiple listeners
• A handheld GPS receiver
• A dedicated GPS receiver

The remainder of this section describes using OpenCPN with a dedicated GPS receiver, however, the instructions for a dedicated receiver will be similar for any serial/USB connected NMEA data stream.

A Dedicated GPS Receiver

There are several companies making dedicated GPS receivers. The Supplementary Hardware section for GPS devices lists several manufacturers.

NMEA has traditionally been implemented as a serial protocol and therefore, even if a USB connection is used, there needs to be a USB to Serial Port conversion. The specific driver for the each GPS receiver will handle this conversion.
 

An Example - Configuring BU-353

 It is not necessary to use the installation disk to setup the BU-353. Following the steps listed below will result in the latest driver being installed.

1. Download the latest driver from Prolific - http://www.usglobalsat.com/s-24-support-drivers.aspx#A
2. Unzip and install the driver
3. Plug in the BU-353.
4. Start -> (Right Click) My Computer -> Properties -> Hardware ->Device Manager
   or Start->Run devmgmt.msc
5. Expand Ports
6. Look for the “Prolific USB-to-Serial Comm Port” and note the com port number (e.g., COM4)
7. Right click on the “Prolific USB-to-Serial Comm Port”. Choose Driver
8. Select 4800 bits per second, 8 data bits, None parity, 1 stop bit, and None for Flow Control 
9. Start OpenCPN
10. Click on the ToolBox Icon
11. Select GPS
12. Under NMEA Data Source select the Com port noted in #6
13. Choose OK
14. Select Auto Follow to center the map over your GPS location

Troubleshooting

There is a small LED located on the BU-353. If the LED is off there is no power being received. Check the connection.

If the LED is solid it indicates the BU-353 is searching for a GPS signal. Try moving the GPS receiver to a clear location.

If the LED is flashing it indicates the BU-353 has a position fix and is transmitting data.

1. Try viewing the NMEA data stream in OpenCPN. Choose ToolBox->GPS->click Show GPS/NMEA Data Stream Window
2. Alternatively, a diagnostic program is included on the installation CD called GPSInfo.exe. Launch this program to install the diagnostic utility.

If it appears that the NMEA data stream is being received, the most likely issue is that OpenCPN is not centered over your location. Click AutoFollow to center the map at your GPS location.

Known Issues

If you change the USB port for the GPS receiver Prolific will reassign the COM port number. This will require repeating steps 4-12 above.

On some computer / GPS receiver combinations when the computer resumes from Stand By the GPS receiver will no longer transmit its NMEA data stream, and only garbage instead of ASCII characters will be visible in the NMEA Data Stream Window. The red indicator led will not work.

To change back to NMEA mode search for and download SIRFDemo.exe.
Unpack and start. Set correct Baud rate and and com port as above.
Click connect to data source button. Action -> Switch to NMEA protocol, then exit.
There are many more settings available in SIRFDemo.exe

An alternative workaround for this issue is provided by using a COM port splitter such as XPort http://curioustech.home.insightbb.com/xport.html

1. Download XPort.
2. Unzip it to a folder of your choice
3. Double Click XPort.exe
4. Set the Baud Rate to 4800
5. Under Enable Ports add an entry for COM10
6. Click “Find GPS”. The port returned should match the port identified in Step #6 in the Configuring BU-353 Section
7. Select Prolific USB-to-Serial Comm Port in the check box section
8. Return to OpenCPN
9. Click on the ToolBox Icon
10. Select GPS

Linux

Two methods are available, direct connection or through gpsd.
We start with gpsd.

• Install the gpsd and gpsd-clients packages
  
  $ sudo apt-get install gpsd gpsd-clients
• Go to Toolbox-->GPS and select "Network GPSD" as your "NMEA Data Source", unless you have a gpsd version in the 2.9.x series( Ubuntu 10.04  and other new distros). In this case choose  Toolbox-->GPS --> "NMEA Data Source" -->"Network LIBGPS". 
• On Ubuntu 9.10 and later, that is really all you have to do. When you plug in your gps this will trigger gpsd to start.
• "xgps" is client that comes with the gpsd-clients package, and is useful for testing that the gps and gpsd is working properly.

Direct connection.

•  Make sure that gpsd isn't running then connect your gps and start OpenCPN.
• In the Toolbox-->GPS --> "NMEA Data Source" the port where you plugged in your gps will come up. If you plugged in BU 353 this will probably be /dev/ttyUSB0.
• Choose 4800 baud, unless you know that the gps is set to something else.
• The gps should now work....if not, check the NMEA data stream window. If only binary garbage is visible, the gps has to be reset to NMEA mode, see more about this above in windows section.
• To do this in Linux for BU 353 as well as many other gps:es, make sure that gpsd is running  and that the package "gpsd-clients" is installed.
• The command $gpsctl -n will put the GPS into NMEA mode.
• If that doesn't work, try $ gpsctl -f -n  /dev/ttyUSB0 .This will force a low-level access, bypassing gpsd. For more information: $man gpsctl
• More information is as always available through "man gpsctl" Close down OpenCPN before running gpsctl.
            
  None of this is normally noticed when using gpsd, as this program reads both NMEA and SIRF binary sentences.
• More Linux hints
• If you can't connect to a physical port, such as /dev/ttyUSBO, indicated by a line in the opencpn.log file. Check that you, as a user, belongs to the group "dialout". To see which groups you belong to, run the command "groups". Not all Linux distributions add the user to this group by default. To add your self to the dialout group -> "sudo usermod -a -G dialout $USER"
• Check if gpsd is working:
  $ ps aux | grep gpsd
  nobody   12338  0.3  0.1   4124  1448 ?        S<s  18:31   0:00 gpsd -F /var/run/gpsd.sock
  you    12356  0.0  0.0   3036   800 pts/3    S+   18:32   0:00 grep --color=tty -d skip gpsd
  This or similar responses indicate that gpsd is running. If you only have something like the second line, ....it is not running.
•  Run the command "$udev monitor" to see exactly, and instantly what is going on when you plugin your gps.
• Run the command "$ls -lrtd /dev/*|tail -10", and see the 10 latest created device files. Run this just after plugin in your gps to see which device was created.
   
• Determine which device your GPS is on your linux system by checking the startup.  Look for a line that says something about GPS and /dev/ttyUSB#
  

  • $ dmesg
    

    Or even better, after connecting a gps mouse, BU-353, we look for a dmesg by running this command.
    

    $ dmesg | grep tty
    and get this response back.
    [13616.095305] usb 2-3: pl2303 converter now attached to ttyUSB0
    
    

• Add a script to start gpsd, if this is not done by your distribution.  I saved mine as startgps and set the executable attribute.  Edit line 3 to match your device, ie /dev/ttyUSB0
  

  • #!/bin/sh
     sudo killall gpsd
     sudo gpsd -n -D 2 /dev/ttyUSB0
     

• Run the script:
  

  • $ ./startgps

Other Distributions

• Install gpsd from source.  More information is available here: http://gpsd.berlios.de/
•  

Bluetooth GPS

Ubuntu.

Fedora

Mac OSX

GPS Status

The default Ownship icon is rendered as grey  if there is no valid gps position fix available
and like this when a gps fix is available

The GPS  status is also indicated all the way to the right along the top of the screen, unless this position is covered by the floating ToolBar. The GPS status is then found bottom left.

 No GPS or Invalid GPS data.

Active/Valid GPS data, but not necessarily a valid position.

Active/Valid GPS data + GPS reporting 0 - 4 satellites, but not necessarily a valid position.

Active/Valid GPS data + GPS reporting 5 - 9 satellites

Active/Valid GPS data + GPS reporting 10+ satellites

The GPS status, including available satellites, is also available as an instrument on the DashBoard

Toolbar Buttons

The Toolbar is floating and can be placed anywhere on the screen, vertical or horizontal.
Note the "grabber" symbol at the far right side of the toolbar. Use this handle to drag the toolbar wherever you want it. The default position is horizontal and docked top left.
It "snaps" to the edges. Right click on the grabber, and the toolbar shifts to vertical format. On Windows (at least), the toolbar dims down transparently until you roll over it.

When a toggle button is pressed, it changes and becomes slightly larger, by adding an outer frame, and grayer. For example

Tracking off , tracking on .

A brief explanation of the use of each button is available by just hovering with the cursor

over a button.

From left to right:

 Zoom In (Zoom In & Out)

 Zoom Out (Zoom In & Out)

 Scale Next Chart Down (Scaling Charts) ¹

 Scale Next Chart Up (Scaling Charts) ¹
 Create Route (Routes and Marks)

 Find/Follow Boat (Auto Follow and Display Orientation)

 Launch Toolbox(Toolbox Settings)

 Show Text Labels on Vector Chart.(Vector Chart Display)

 Show AIS Targets ^{2  3} (AIS)

 Show/Hide Currents On Chart (Tides and Currents)

 Show/Hide Tides On Chart (Tides and Currents)

 Print ⁴

Route/Track/Waypoints/Layer- Manager.(The Route Manager and Data Import/Export)

 Toggle Track On/Off ⁴ (Ship Track)

Adjust Screen Brightness for Dawn/Dusk and Night viewing.(Night Navigation)

 Drop Man Over Board(MOB) marker(Man Over Board)

 About OpenCPN and Help File
Show/hide the Dashboard Plugin ⁴ (The Dashboard Plugin)
 Grib Overlay Plugin ⁴ (GRIB Weather Plugin)

A separate GPS status and Chart Orientation Status is normally in the upper right corner of the display, unless the floating ToolBar covers this position. Then the "Staus-bar" will be moved to the lower left corner, were it will stay, unless the main ToolBar iis moved to cover this position, in which case the "Status Bar" goes back to the default position.

 Course Up/North Up ³ (Auto Follow and Display Orientation)

Right-click Menu

The basic raster chart right-click menu

Max Detail Here

Scale In

Scale Out

Drop Mark Here

Move Boat Here

Go to Here

Jump to Position...

Set North Up Mode

Measure

AIS target list

The basic vector chart right-click menu

Object Query

Zoom In & Out

  These buttons allow you to zoom in and out on the chart currently being displayed.  

 Will zoom the chart in for more detail, larger scale.

 Will zoom the chart view out for more area, smaller scale.

Alternatively, the + and - keys on your keyboard will zoom in and out.  If you have a mouse with a scroll wheel, it can also be used to quickly zoom in and out.

 

Overzooming

Status Bar

On the bottom is the Status Bar(s). Activated from 'Tool Box-Show Status Bar'.

The top line, 'Chart Selection Bar', has the following description.
It shows all the available chart for the present view represented by one segment for each chart. The order between the segments represents the scale of the charts. Largest scale to the left, smallest to the right. If CM93 is available, it is always furthest to the right.
The segmented color bars in the Status Bar represent:

• Blue for Raster
• Green For ENC's
• Brown/Yellow for CM93 charts
• The current chart displays as a lighter shade of its color, or if quilting is active, the charts currently making up the quilt are displayed in lighter shade.
• The Chart bar below consisting of 12 segments shows a quilt of two active charts. Five charts in the quilt are hidden, due to small scale. CM93 is in it's place, to the right. Four charts of larger scale than the present view are available. The largest scale chart is a Transverse Mercator chart.

Limitation

When you hover the mouse pointer over the bar, and not in quilting mode, a thumbnail of the chart will appear under the Scaling Charts icons and a chart information box will pop up just above the button. If quilting is on, instead of a thumbnail, the chart represented by the button will be highlighted in a transparent reddish color. By clicking on the appropriate bar, or using the appropriate Hot Keys, you will switch to the chart shown in the thumbnail. This feature is especially useful if you wish to view an ENC or a Raster chart of the same area.

The bottom line starting from the left, has the position of the GPS that feeds OpenCPN (your ship or boat). SOG, COG, Cursor (position), From Ownship and TrueScale and Zoom Factor are in other boxes. If the Zoom Factor is missing on the far right, the chart quilting feature is activated.

The buttons are displaying a lot more information however.
 

   These buttons shows that the two charts are Transverse Mercator.

   This button indicates that the chart is a Poly Conic  chart.

   This button shows that the chart is skewed.
 

    This chart is excluded from quilting because of user action. Right
click to  include in quilting again.

    The raster chart represented by this button don't participate in the quilt because it is hidden by other, larger scale charts. Vector charts are represented similar.

To illustrate a lot of this, here is a screen shot in quilting mode.



The screen is a quilt of two Polyconical charts. Hovering the mouse pointer over the left chart-button highlights the lager scale chart for Manitowoc. Two smaller scale charts that cover the area displayed on the screen are included in the quilt, but are invisible as they are covered by the larger scale charts. To view these charts, right-click anywhere on a chart in the quilt and select "Remove this chart from quilt", one of these charts will now be shown in the quilt.
The Brown right most button shows that CM93 version 2, charts are available for the area, but not currently displayed.
The information box shows relevant information about the chart. We can see that the chart is  Polyconic, and because of this a warning is displayed for poor accuracy. The reason is, that although Polyconic charts are allowed to participate in quilting, the result is not totally free from errors, however small.


 

All About Charts

Chart Quilting

Chart quilting is a way to display parts of several charts together on the screen, redrawn to the same scale.

Limitation
Mercator charts, Transverse Mercator charts and Polyconic chart are quilted separately and don't mix. The transition from one form of quilting to the other is seamless. Black areas can appear in Tmerc and Polyconic quilt in areas where there is no chart cover.
By quilting, any information available in the white border around a chart, will be hidden.
To see this information hit "F9" to temporarily get into single mode display.
Skewed charts don't quilt, unless the skew is less than 5°.

Quick Start
Go to ToolBox -> Settings -> Enable Chart Quilting. Tick he box. Once quilting is on in the Toolbox, F9 becomes a toggle switch to temporarily get into single mode display. Zooming in, automatically brings up larger scale charts, if available. Panning reveals a continuous quilt of the available charts. If you started with a raster chart, only raster-charts, and perhaps CM93, will be in the quilt. The same logic applies to S57 Vector Charts (ENCS). Make sure you are familiar with the Status Bar as this will help you interpret all available information. The quilt, like a single chart can be displayed North Up or Course Up read more:  Auto Follow and Display Orientation.

More details
What is the use of this feature?



In single chart mode, getting near the edge of the chart there is no information outside the chart.

 

The situation changes dramatically when quilting mode is activated. The amount of  relevant information on the screen increases.

Displaying charts

OpenCPN has two modes of displaying charts, single chart mode and quilting mode.

To activate chart quilting go to Toolbox -> Settings -> Chart Display Options and tick the box "Enable Chart Quilting",  tick the box "Show Chart Outlines" at the same time as this will help you see which chart mode is active. For CM93 the outline of individual charts can bee seen only if quilting is disabled.

Full Screen Quilting. Toolbox -> Settings -> Disable Fullscreen Quilting. By default all visible charts of an appropriate scale are used in the quilt. With this box checked only charts that overlap the center of the screen are used in the quilt. Checking this box is easier on the system and may give a performance boost in certain circumstances.

Is Chart quilting on?
There are some visual indications on screen to confirm if quilting is on or off.

• The colored rectangles in the status bar have rounded corners and the white borders of the charts are invisible when quilting is on. When quilting is off the colored rectangles has square corners.
• If you have the status bar visible at he bottom of the screen "zoom + factor" to the far right, is only shown in single mode.
• When hovering with the mouse pointer over a inactive raster chart button in single chart mode, a thumbnail of the chart is displayed in the upper left corner of the screen. At the same time an information box pops up above the button with details about the chart.  This changes with quilting as the thumbnail is replaced with a high-lighting of the charts part in the quilt with a transparent reddish color.
• The exception to the last rule is CM93 charts. When an area is only covered by CM93 charts, indicated by a long yellow chart button in the status bar, and in quilting mode, no info-box is displayed and no reddish highlighting is taking place.
• When CM93 quilting is off, the outline of the individual cells are outlined in magenta.

More than one chart can be displayed and active at the same time, on the picture above, for example there are three pale blue buttons, as there are three raster-charts in this quilt. In single mode only one chart button is highlighted at a time.

Depth units that is normally shown in the upper right corner of the display, if activated in the toolbox, is only displayed in quilting mode if all participating charts  uses the same unit.
Zoom level, normally displayed on the far right on the Status bar, is not present in quilting.

Many of these features are illustrated in this screen-dump.



This is a quilt consisting of three raster charts, two that are actually displayed and one smaller scale chart that is hidden behind the larger scaled charts of St Croix.
  This is the button for the not displayed chart in the quilt.
The mouse pointer is over the middle raster chart and the chart information box is shown, together with the red highlighting of the chart on the screen.
No depth unit is shown in the quilt as the left chart is in Feet and the right in Fathoms an parts thereof. Notice the lack of zoom level in the status bar, a quilt , by definition, consists of several different zoom levels.

Which charts are quilted?
There are several rules built into OpenCPN governing exactly how different charts reacts to the quilting mode.
Raster charts and Vector charts are quilted separately and don't mix together. You can quilt either raster charts or vector charts, but not both at the same time.
The exception to this rule is that CM93 ver2 charts, if available, are shown if no other Mercator chart cover exists for a displayed area, for both raster- and vector- chart quilting.
Transverse Mercator Charts, which are all raster charts, are strictly quilted on their own. In this case, black areas can occur where there is no coverage.
Polyconic Charts, which are all raster charts as well, are also strictly quilted on their own. In this case, black areas can occur where there is no coverage.

CM93 ver2 charts can be quilted separately.

Mercator Charts are always quilted in quilting mode but don't quilt together with Transverse Mercator charts or Polyconic charts.
Polyconic Charts, are quilted separately, and don't mix with Mercator or Transverse Mercator Charts
Skewed Charts are allowed in the quilt as long as they don't deviate more than 5 degrees
from North Up.
Transverse Mercator Charts  are quilted separately from Mercator- and Polyconic- Charts.

User control.
Users can control if an individual chart, is allowed in the quilt or not. Right clicking on any chart in a quilt and clicking "Remove this chart from quilt" on the pop up menu, removes the chart from the quilt. The chart button in the Status bar changes to .
To activate the chart again right click this button an then click "Ad this chart to quilt"

Known issues with some NOAA ENC:s



Some NOAA ENC:s are produced with "holes" in. OpenCPNs present quilt handling is not geared to handle this, and gray areas can under some circumstances be visible. The picture above is from S:t Croix in the Caribbean. Gray areas of three different kinds are visible.

The Northern gray rectangle is an "unsurveyed" area, where, strangely enough, a smaller scale chart is available with a "survey". Use the ChartBar to switch to the smaller scale chart if necessary. Note the black frame.

The Middle two gray rectangles are "holes" in a small scale chart, where larger scale charts exists. Once again use the chart bar. Tick  Toolbox->Etc "Preserve scale when changing charts" to keep the same scale when switching to larger scale charts. Note that the areas are framed in green, indicating that larger scale charts are available.

The Southern gray rectangle is a "hole" with no information available at all, and no other ENC charts are available. Note that there is no frame at all around this area.

Chart Groups

Chart Groups solves the following problem: You may have many charts loaded in your active database. Some of them have overlapping coverage at the same scale, so that when quilted the logic does not know which of potentially several charts at the same scale to choose from. For example, in the Bahamas there are a few publishers of charts, covering the same areas, with radically different presentations. Sometimes you may want to see one set (say planning charts of small scale), and other times you only want navigation charts of the best scale possible.

Another example: Pilot charts as one Group, normal navigation charts as another Group, makes it possible to quickly switch between them.

Final example: in another universe, NGA charts in one group, standard NOAA RNCs in another, British UKHO in a third group.

The Chart Group function allows us to define multiple Groups, with different chart directories in each group. The Group desired for viewing may be selected quickly without adding or deleting charts from the Active database.




In Toolbox->Charts, select "Chart Groups"
You will see two panes. The left pane contains you installed ("Active") chart directories. The right pane allows you to create, edit, and delete Groups. Note that there is always a "Group 0", which is all "Active" charts. This Group is not editable. New Groups which you create may have chart directories or individual charts added to them by selecting the item in the left pane, and touching the "Add-->" button.

You may also remove individual charts and/or directories from within added items by selecting the desired item in the right pane, and touching "<--Remove". Please note that "removing" an item from the Group does not remove it from your "Active" set. The item is simply made unavailable when this Group is in use.



This dialog comes up when pressing the  "Chart Groups" Button.
A few chart groups are defined.



In this illustration the navigator generally uses the US charts, when available. Coming into Baia do Porto Santo a detailed chart would be great, but no such US chart is available on board. A switch to the UK chart group solves the problem.






Select the Group you want to currently use by a right-click context menu item called "Chart Groups". As you switch Groups the logic tries to select a chart and scale that closely matches the situation present before the switch. As you may understand, sometimes the fit is not reasonable, so the resulting view may be surprising.

Finally, if you have no Groups defined, as in the default installation, the operation of OCPN will be as in 2.5 legacy releases. All installed charts are available always.

Chart Groups and CM93



It is possible to have multiple instances of CM93v2 in different Chart Groups. Above we have 5 instances loaded in various chart groups. The view is of "All Active Charts".
The instances are loaded, from left to right, in the order of the chart groups.
In this situation, only the leftmost instance of CM93, that is not excluded from the quilt, will be displayed. Above, it is the instance represented by the yellow rectangle.

Vector Charts

First, one very important setting for vector charts is handled directly from the main toolbar.
This button toggles all text displayed on a vector chart On and Off
 
Second, double clicking any point on a vector chart brings up an information dialog, displaying  the available vector-chart information at the selected point. Scroll down to see all the information. An alternative to double clicking is right-clicking an select "Object Query".
Note that a single normal (left) click will center the chart at on that point.


 
The example is taken from double-clicking on a buoy in a busy area.
Exactly what is shown in this dialog depend on the settings described below in "Display Categories".

Third, The ToolBox Vector Charts Tab is where everything else is handled.

Display Categories

Navigators has the choice  of three pre-defined, different, presentations of ENC content, Base, Standard and Other. OpenCPN also has the very flexible Mariners Standard, which is better described as "Mariners Choice".

Base

Displays general  information, including coastline, safety-contour, isolated danger,
buoy, beacon traffic separation zone, etc.

From the IMO definitions:
Display Base means the level of SENC information which cannot be removed from
the display, consisting of information which is required at all times in all geographic areas and all circumstances. It is not intended to be sufficient for safe navigation.

Standard

Everything in "Base" and aids to navigation, fairways, channel limits, restricted navigation zones, restricted areas, etc..

All  Other Information

Everything in "Standard" and more. This level could be described as "all essentials". More about what the the standards says about the content of these three levels.

Mariners Standard

Users can use  the filter tick box to set exactly what he or she wants displayed. A large set of filters, about 186, can be employed. They are all to the IHO S57 standard, and it is recommended to download S-57 Appendix A - IHO Object Catalog and have a copy onboard. Use your pdf viewers "search" or "find" function to quickly find what an acronym means.
Note that Mariners Standard gives the user a much wider choice of what to display, than approved ECDIS system are allowed. It is for example possible to not display items in the Base category.

WARNING - it is possible to suppress essential information with "Mariners Standard".

If in doubt, switch to "Other", or use the "Select All" button.

Details can also be found on the Internet:
caris.com
s-57.com/
help.arcgis.com
To illustrate the way of thinking behind  the acronyms, here are a few examples.

LNDARE  = LANDAREA
TESARE   = TERITORIAL SEA AREA
NAVLNE  = NAVIGATION LINE
PIPOHD = PIPELINE OVERHEAD
SLOTOP = SLOPE TOPLINE
SLCONS = SHORELINE CONSTRUCTION

Each acronym also has an exhaustive official formal definition:

DEPCNT = DEPTH CONTOUR   A line connecting points of equal water depth which is sometimes significantly displaced outside of soundings, symbols and other chart detail for clarity as well as generalization. Depth contours, therefor, often represent an approximate location of the line of equal depth as related to the surveyed line delineated on the source. Also referred to as depth curve.
 

Reference for Mariners standard

$AREAS	Cartographic area	
$COMPS	Compass	
$CSYMB	Cartographic symbol	
$LINES	Cartographic line
$TEXTS	Cartographic text
_extqn	
_texto	
ACHARE	Anchorage area
ACHBRT    Anchor berth
ACHPNT	Anchor
ADMARE	Administration Area (Named)
AIRARE	Airport/ airfield
BCNCAR	Beacon, cardinal
BCNISD	Beacon, isolated danger
BCNLAT	Beacon, lateral	
BCNSAW	Beacon, safe water
BCNSPP	Beacon, special purpose/general
BOYCAR	Buoy, cardinal
BOYINB	Buoy, installation
BOYISD	Buoy, isolated danger
BOYLAT	Buoy, lateral
BOYSAW	Buoy, safe water
BOYSPP	Buoy, special purpose/general
BRIDGE	Bridge
BRTFAC	Berthing facility
BUAARE	Built-up area
BUIREL	Building, religious
BUISGL	Building, single
CANALS	Canal
CANBNK	Canal bank
CAUSWY	Causeway
CBLARE	Cable area	
CBLOHD	Cable, overhead
CBLSUB	Cable, submarine
CEMTRY	Cemetery
CGUSTA	Coastguard station
CHIMNY	Chimney
COALNE	CoastDEPCNT	Depth contourline
CONZNE	Contiguous zone
COSARE	Continental shelf area
CRANES	Crane
CTNARE	Caution area
CTRPNT	Control point
CTSARE	Cargo transhipment area
CURENT	Current
CUSZNE	Custom zone
DAMCON	Dam	Barriere
DAYMAR	Daymark
DEPARE	Depth area
DEPCNT	Depth contour
DIFFUS	Diffuser
DISMAR	Distance mark
DMPGRD	Dumping ground
DRGARE	Dredged area
DRYDOC	Dry dock
DSHAER	Dish aerial
DWRTPT	Deep water route part
EXEZNE	Exclusive economic zone
FAIRWY	Fairway
FERYRT	Ferry route
FLASTK	Flare stack
FLODOC	Floating dock
FNCLNE	Fence
FOGSIG	Fog signal
FORSTC	Fortified structure
FSHFAC	Fishing facility
FSHGRD	Fishing ground
FSHZNE	Fishery zone
GATCON	Gate
HRBARE	Harbor area
HRBFAC	Harbour facility
HULKES	Hulk
ICEARE	Ice area
ISTZNE	Inshore traffic zone
LAKARE	Lake
LAKSHR	Lake shore
LIGHTS	Light
LITFLT	Light float
LITHOU	
LITVES	Light vessel
LNDARE	Land area
LNDELV	Land elevation
LNDMRK	Landmark
LNDPLC	Landing place
LNDRGN	Land regiom
LNDSTS	Landing stairs
LOCMAG	Local magnetic anomaly
LOGPON	Log pond
LOKBSN	Lock basin
M_COVR	Coverage
M_HOPA	Horizontal datum shift parameters
M_NPUB	Nautical publication information
M_NSYS	Navigation system of marks
M_PROD	Production information
M_QUAL	Quality of data
M_SREL	Survey reliability
MAGVAR	Magnitic variation
MARCUL	Marine farm/culture
MIPARE	Military practice area
MONUMT	Monument
MORFAC	Mooring/Warping facility
MSTCON	Mast	Mast 
NAMFIX	
NAMFLO	
NATARE	National territorial area
NAVLNE	Navigation line
OBSTRN	Obstruction
OFSPLF	Offshore platform
OFSPRD	
PILBOP	Pilot boarding place
PILPNT	Pile
PIPARE	Pipeline area
PIPOHD	Pipeline, overhead
PIPSOL	Pipeline, submarine/on land
PONTON	Pontoon
PRCARE	Precautionary area
PRDARE	Production/storage area
PRDINS	Production installation
PYLONS	Pylon/bridge support
RADDOM	Radar dome
RADLNE	Radar line
RADRFL	Radar reflector
RADRNG	Radar range
RADSTA	Radar station
RAILWY	Railway
RCRTCL	Recommended route centerline
RCTLPT	Recommended traffic lane part
RDOCAL	Radio calling-in point
RDOSTA	Radio station
RECTRC	Recommended track
RESARE	Restricted area
RIVBNK	River bank
RIVERS	River
RMPARE	Ramp
ROADPT	Road part
ROADWY	Road
RSCSTA	Rescue station
RTPBCN	Radar transponder beacon
RUNWAY	Runway
SBDARE	Seabed area
SEAARE	Sea area/named water area
SILBUI	Silo
SILTNK	Silo/tank
SISTAT	Signal station, traffic
SISTAW	Signal station, warning
SLCONS	Shoreline construction
SLIPWY	Slipway
SLOGRID	Sloping ground
SLOTOP	Slope topline
SLTPAN	Salt pan
SMCFAC	Small craft facility
SNDWAV	Sand waves
SOUNDG	Sounding
SPLARE	Sea-pland landing area
SPRING	Spring
STSLNE	Straight territorial sea baseline
TELPHC	Telepheric
TESARE	Territorial sea area
TIDEWY	Tideway
TNKCON	Tank
TOPMAR	Topmark
TOWERS	Tower
TREPNT	Tree
TS_FEB	Tidal stream - flood/ebb
TS_PAD	Tidal stream panel data
TSELNE	Traffic separation line
TSEZNE	Traffic separation zone
TSSBND	Traffic separation scheme boundary
TSSCRS	Traffic separation scheme crossing
TSSLPT	Traffic separation scheme lane part
TSSRON	Traffic separation scheme roundabout
TUNNEL	Tunnel
TWRTPT	Two-way route part
UNSARE	Unsurveyed area
UWTROC	Underwater/awash rock
VEGARE	Vegetation area
WATFAL	Waterfall
WATTUR	Water turbulence
WEDKLP	WEED7kelp	
WIMCON	Windmotor
WIRLNE	Weir
WNDMIL	Windmill
WRECKS	Wreck
ZEMCNT	Zero metre contour

Practical usage

A general recommendation would be to use "Mariners Standard" and to "Select All", to start with, and then switch of certain features as required.

As an example let's look at passing through the British gas fields in the SW North Sea



This is not easy, so we want to get rid of all those red and yellow circles.
Right click on one of the platforms, square with a dot.



Click "Object Query", and then one of the "Light" lines in the left column.



At the top of the right column i says "Feature Class: LIGHTS".
Find "LIGHTS" in the Mariners Standard list of available filters.



Untick LIGHTS.



Much better!

ShowSoundings

turns the measured depths on and of. Other settings also affects when soundings are displayed, for example SCAMIN. The dark black numbers are not soundings. Instead they refer to heights of nearby islets or cays. On official paper charts the soundings are printed in italics.



The bold number 20 refers to the land height of the unnamed cay SW of the number.
"Safety Depth" is set to 20 m, so all soundings greater than 20 are gray, while those less than 20 are black.

META objects

relates to information about the chart itself. With this switch on, an object query reveals such information as the buoyage system for the area and the quality of the survey.

Show Important Text Only

displays only a bare minimum of text essential for navigation, such as course and bearing in a leading line (range) and bridge clearances.

Use SCAMIN

makes sure that objects are only shown at a relevant minimum scale. Without SCAMIN everything is always shown, leading to very cluttered view at small scale (zoomed out).

Show ATON labels

displays names and purposes of Aid To Navigation, such as number or name of buoys, information about conspicuous objects etc

Show light description

this tick box control display of light characteristics. Checking this displays  a label with a text describing the marker or lighthouse's characteristics.

De-Clutter Text

Even when using SCAMIN there are cases when text labels overlaps or overwrites other labels and creates a cluttered impression. Ticking this box clears up this mess. To see all the labels, increase the scale for the area.

Chart display style

Points

Paper chart draw the markers and lights just like the printed paper chart, while simplified uses icons to represent the same. Some like the one and some the other, a matter of taste.
Paper Chart mode closely follows the IHO standard standard in this area. This mode is currently more developed than the simplified mode, as it has a higher priority in the development effort.

Boundaries

Plain normally just uses a dashed line, while the Symbolized version also uses triangles pointing into the area.

Colors

Depth on the chart can be displayed with either 2 or 4 colors. This setting is closely related to the "Depths Settings". With 2 colors, and using a relatively large scale, areas with depth less than "Safety Depth" is blue, the rest is white. With 4 colors, there are different colors for areas less than "Shallow Depth", areas between "Shallow Depth" and "Safety Depth", areas between "Safety Depth" and "Deep Depth" and finally for areas deeper than "Deep Depth".

 

CM93 Zoom Detail

Normal settings depend on a combination of personal preferences and present usage of map. To see more detail the "Zoom detail" can be set to a higher positive number or for navigation in shipping lanes to a negative numbers. Typical zoom level 5 is good for fishing when as much details are possible is of interest. Zoom level of +1, zero or -1 is usually fine for normal use.
Positive values give more detail, but at a cost:
a. It simply takes longer to render larger scale charts covering more screen real estate.
b. There will be more instances of gray (NODATA) areas surrounding the larger scale charts as you zoom out, unless quilting is activated.
c. It can become dramatically slower if high detail is specified, and chart outlines are requested. In this case, the program has to read a lot more cells to get their outlines.

Conversely, negative values give less detail. Zooms are faster.

In non quilting display mode, the slider can be activated through the right click meny, and displayed directly on the screen.

Depth Settings

These settings are very important as they affect how the different depths are colored.
They can help you identify a deep channel for example, or they can, in  the worst case secenario, prevent you from beeing aware of a shallow area.
There is no setting that fits all circumstances. For example a Seamount with a depth of 20m  in the middle of an ocean should be regarded as "shallow" and be avoided, while 20 m depth in a harbor approach in protected water, probably is safe.

The Depth Settings controls the coloring of the water as a function of depth. By setting the Safety and Deep water right you will have a visible border to show when to take care about shallow water. 
CM93 charts and S57 ENCS works very similar in this area.The charts contains depth area features according to fixed depth cutoff zones, usually 5, 10, and 20 meters. Intermediate values are not available in the database,if you select a value between those available, opencpn chooses the next higher value available for display of color.
The charts are inconsistent in this area, depending on the country issuing the original  charts. For example in UK and the Netherlands the depth contours in CM93 are 2, 5 and 10 meter while in Sweden they are 3, 6 and 10 meter!
Generally for both S57 ENC and CM93, find these fixed depth cutoffs by right clicking -> Object Query ->Chart -> Depth Area. The two values DRVAL1 and DRVAL2 represents these built in cutoffs.
If for example, as is the case on the South China Sea Hydrographic Commissions charts, the shallowest area has a   DRVAL1 = 0 m and a DRVAL2 = 10 m, there is, in most cases, no point in setting "Shallow Depth" to anything but 10 m.
Find out these cut off depth for your area and set the "Depth Settings" with this knowledge together with your preferences and activity.

Note that Shallow,Safety and Deep Depths are always in meters, even if soundings are chosen to be displayed in another unit.

With all the reservations above, the general case for 4 colors, will be described.

Shallow Depth

will color all water areas with water depths shallower than the set depth to a dark blue color.Soundings are in black.

Safety Depth

water deeper that Shallow but shallower that this depth will have a paler blue color. The  Shallow Depth contour clearly marked with dark gray borderline.Soundings less than this depth are in black, while soundings greater than this value are gray.

Deep Depth

water deeper than Safety Depth but less than Deep Depth will display a light gray color. The  Safety Depth contour  is clearly marked with black borderline. Water deeper than Deep Depth is displayed in white.

Finally a word about drying heights, displayed in green. There is no detailed information available for the value of the drying heights, neither in CM93 ver2 nor in many S57 charts, currently available for OpenCPN. Some S57 charts have negative DRVAL1  and  DRVAL2 = 0 m in areas with drying heights. This adds very little, as it really only gives the information that the drying height is less than DRVAL1 in an area of unspecified size. Raster charts seems to be the only alternative for navigation in shallow areas with a large tide.

Hopefuly this will change.
A set of new charts released in april 2012, by the Dutch Authorites, sets a standard for others to follow in this regard.



Compared to CM93.



When is safe to pass across Bramble Bank? The CM93 vectorchart gives us no information whatsoever, neither on the chart, nor in the Object Query dialog.



While a raster chart tells us that we need a Hight of Tide that is 1.2m + safety margin + the draft of our own vessel.



Heights of islands etc. are not available in CM93, while S57 charts have info about heights of summits and peaks but no contour lines.
Is Balls Pyramid a high Island, that the name implies, or is it named with the same sarcastic humor as "Greenland" ? CM93 can't tell.

Auto Follow and Display Orientation

• Clicking the Auto Follow button  will center the chart directly on your vessel's current location. If the the gps is working  own ship is red otherwise the icon is gray. . If zoomed out to a scal that is smaller than 1:300.000 the icons changes to , when receiving gps signals and otherwise. More about he OwnShip icon is available here.
• The default own ship icon can be replaced by  putting a file "ownship.xpm" in the User icons shared data directory. More about this  shared directory here: Routes and Marks
• The Auto Follow button useful for two different situations:

1. When you have panned the map away from your current location and want to quickly move back to your vessel.
2. When underway, this will keep the display on the chart around your vessel, with the boat at the center of the chart.

• Note: Panning the chart will disable this mode. Simply click  again to turn Auto Follow mode back on.
• The display can be oriented three different ways, normally it is North Up but  Course Up is an alternative. With Course Up OpenCPN uses COG, course over ground. The easiest way to change between these two modes is through the "Right Click" menu. One situation where course up might be considered is when navigating a river or a canal. The third orientation is when skew charts are displayed, they are simply shown as "Chart Up",  but an optional setting exist to show them as "North Up".
• If the option "Show skewed raster charts as North-up" in the Settings tab, is not ticked, the right-click toggle option "Set Course Up Mode/Set North Up Mode" will be replaced by "Set Course Up/Set Chart Up", for skewed charts.
• If an electronic compass is available in the NMEA stream the own ship icon will be orientated according to this heading. The difference can be seen on the chart if there is a cross current, for example.  The boat below is heading WNW but is being set SW. An AIS CPA, Closest Point of Approach is also visible.    
• 
•   This icon (blue color) to the far right in the ToolBar indicates that the display is in North Up mode.
• The red version of the icon indicates Course Up  mode. These setting can also be controlled in the ToolBox -> Settings -> Chart Display Options ->Course Up Mode
• Note that both the red and the blue arrows are always pointing North.
• Look Ahead! To see more of the chart in front of the boat, activate ToolBox -> Settings -> Chart Display Options ->Look Ahead  Mode. Your own boat will no longer be in the center of the screen. Instead it will be located away from the center, in the opposite direction to your present gps course(COG).
• Don't always Look Ahead! If you are at anchor, swinging on the hook produces random courses and low speeds.If Look Ahead is on in this situation  the chart rendering will constantly be redrawn, with the boat in all possible lookahead positions as the course changes. To prevent this kind of scenario OpenCPN works like this:
  *If the boat speed is less than 1 kt, then lookahead is disabled.
  *If boat speed is greater than 3 kts, lookahead is enabled.
  *In between 1 and 3 kts, the lookahead "distance" is adjusted smoothly.
  *If  the problems still there when doing more than 3 kts, consider using  "ToolBox->GPS-FilterNMEA Course and Speed data"  to average out the "jumpiness".
• Show skewed raster charts as North-up. Skewed charts are normally showed "skewed up", as it is intended. If ticking this box, these charts are shown North-Up by default. In both cases, activating course up, works as expected, the difference is when course up is not on.

 

Tides and Currents

Notes

• Tide and Current predictions are not available for all areas.
• As with all predictions, the displayed values are calculated using mathematical models and actual tides and currents will vary

Enable Tides and Currents Display

• Click the toolbar button  to see tide stations.
• Select  to see current stations.
• Important: tide and currents will not be displayed unless these toolbar buttons are selected.

Displaying Tides

• Available tide stations will show on the chart as green graphs with a "T" logo:
• The "T" becomes a yellow and blue vertical bar when the scale is greater than 1:500.000

• The vertical bar contains a lot of information at a glance.
• The tidal rise is 2.5m above the chart datum. The blue part is "water". The  "V" inside he bar indicates that the tide is decreasing towards Low Water.
   
• Here, the tide is rising towards High Water.
• Low Water looks like this.
• High Water Looks  like this.
• Right click the middle of either icon to see the tidal graph:

• The Yellow box, with the tidal rise and time, follows the cursor when hovering over the dialog. The time axis at the bottom displays the time, in this case he timezone is "Z +01:00", which is the same as one hour ahead (east) of UTC, that used to be called GMT.
• In North America it is common to use a three or four letter acronym for timezones.

CODE

UNITED STATES TIME ZONE CODES

UTC OFFSET

AST

ATLANTIC STANDARD TIME

UTC - 4

EST

EASTERN STANDARD TIME

UTC - 5

EDT

EASTERN DAYLIGHT TIME

UTC - 4

CST

CENTRAL STANDARD TIME

UTC - 6

CDT

CENTRAL DAYLIGHT TIME

UTC - 5

MST

MOUNTAIN STANDARD TIME

UTC - 7

MDT

MOUNTAIN DAYLIGHT TIME

UTC - 6

PST

PACIFIC STANDARD TIME

UTC - 8

PDT

PACIFIC DAYLIGHT TIME

UTC - 7

AKST

ALASKA TIME

UTC - 9

AKDT

ALASKA DAYLIGHT TIME

UTC - 8

HAST

HAWAII-ALEUTIAN STANDARD TIME

UTC - 10

HADT

HAWAII-ALEUTIAN DAYLIGHT TIME

UTC - 9

SST

SAMOA STANDARD TIME

UTC - 11

SDT

SAMOA DAYLIGHT TIME

UTC - 10

CHST

CHAMORRO STANDARD TIME

UTC +10

Displaying Currents

• Available current stations will show on the chart as orange diamonds, when zooming in arrows will appear pointing in the direction of the set. Note that "current" here is the same as the UK term "tidal stream".
• Master current stations are shown like this in all scales. No direction is associated with these stations but they can be queried, trough a right click, for the magnitude of the current.

• Arrow indicates current direction and strength - the bigger the arrow, the more current.
• The size of the arrows can be customized by users in the opencpn.ini (opencpn.conf) file.
  In the [Settings/Others] section you can set the option CurrentArrowScale to a positive number representing a percentage scaling factor of the current arrows. The values bellow 100 mean the arrows will be smaller than now, the values above 100 will cause them to be bigger.
• Right click the orange box  to see current graph:

• The Yelow box, with time,speed and direction, follows the cursor when hovering over the dialog.

 Using an alternative data set

• The default dataset for tides and currents is limited, mainly for copyright reasons.
• A number of different datasets are available on the Internet, with vastly greater coverage. Some of this data is getting aged, and they also contains glitches and errors, many of which has been corrected in the default dataset.
• In many areas there are no free alternatives, and OpenCPN makes it possible to quickly switch between data sets.
• Create a folder UserTCData in your user data folder. Under this subfolder you can then create any number of subfolders, each containing the HARMONIC/HARMONIC.IDX file pair with different data. It will look something like this
• 
• Go to Toolbox->Settings->Tides & Currents. The button to the right will now look like this:
• 
• To use a different dataset than the default, simply click it.

Marks and Routes

Marks...

Creating a mark

• Pressing "Enter" creates a mark at the cursor position.
• "Ctrl + M" creates a mark at the cursor position.
• Rightclick and and press "Drop Mark Here" creates a mark at the position of the cursor when clicking.
• Marks are created at the start of each leg in a route, and one at the end of the route. More about routes a bit further down this page.

You can move the mark by left-click-dragging it around.

You can delete a mark by right-clicking its icon, and selecting "Delete Mark".
All marks have properties that can be seen by rightclicking and pressing "Mark/WP Properties".
Read all about the properties dialog this page.
Marks can be manipulated through the Route Managers Waypoints tab as well. Deleting a mark that is part of a route, will also change the route.Marks that are a part of a "layer" cannot be changed at all. Marks can also be imported into OpenCPN in a number of ways.
Read all about the  Route Manager and Layers here.

A general  locking of  all marks is available. Goto ToolBox->Etc.

and tick the box. This feature is handy, to prevent accidentally moving a mark. Activate this feature when underway, deactivate it when planning.

The Man Over Board mark  can be activated through the icon in the toolbar, or through hitting Ctrl + Space-bar. The mark looks like the button and is dropped on present position. This mark cannot be moved or deleted with the cursor or keyboard (by mistake), but can still be deleted from the Route/Waypoint manager dialog. More about MOB here.

All the details of the Mark/WP Properties dialog are dealt with on this page.

 

Use your own Icons

Size of Own Ship Icon and location of the GPS antenna.

Routes

Press the -button and start  the creation of a route.  When clicked the cursor changes to a  ( ) pencil when you moce off the button. Left click along the desired route you want to make. This will leave sequential numbered waypoints as you click along, the numbers will not be visible, but are available in the Route Properties Dialog, accessible through the right click menu or the Route Manager. The running total distance of the whole route will be shown along the "pencil" together with the course from the last marked waypoint. When creating routes, OpenCPN will ask if it should use a nearby mark, when a route point is added that is close to an already existing mark.



If your desired route extends off the currently displayed chart, move the route cursor in the desired direction and the display will automatically pan to show the area.  You can zoom in and out with the mouse scroll wheel or keyboard +/- keys during route creating.  You can also right click and select 'MAX DETAIL HERE' or 'Scale Out' during route creation. When finished right click and choose end route from the context menu, alternatively just press the "Esc" key.

The right click menu is context sensitive, exactly what you get depend on what sort of chart it is and if quilting is activated, for example.
You should now have an inactive (Blue) route.  Active routes are Red, inactivated routes are Blue.
Right clicking on a route brings up a menu with many alternatives, such as "Insert Waypoint" and "Append Waypoint".

Multiple Routes 

In OpenCPN multiple routes can be handled in a couple of different ways.
Many routes can be created in a session or imported into a session.
The visibility of every route is controlled in the Route Manager. There is an "eye" to the far left on the line for each route. This works as a toggle switch.
This way only the route(s) of interest for the moment can be shown.

Another way is to create and export routes, and later import them when needed.
To keep the chart clear of useful but un-needed routes follow these steps:
• Create a folder called, 'GPX_Routes', or another suitable name.
• Create your route.
• Use the Route Manager to export the route, with a descriptive file name and save it in GPX_Routes.
• Delete the route from the chart.
• You can export all your routes as one big file or export and delete a route as you create them
• When needed, simply use the Route Managers "Import" Button to open the route file. 
 

To get rid of the way points left on the chart when a route has been imported and then deleted, which may happen depending on the imported gpx file.

1. Open the Route Managers Waypoint tab and press the "Delete All" button
2. Say 'Yes' to: 'Are you sure you want to delete <ALL> waypoints?'

Saving and Loading Routes and Marks

• Refer to The Route Manager and Data Import/Export to load and save data using The Route Manager

Activating and using routes

• Activate Waypoint - Gives the direction to the chosen waypoint instead of the first waypoint in the route, which is the default. Useful when joining, for example, an imported route, at an arbitrary waypoint.
• Activate Next in Route. Sometimes it makes more sense to go directly the following waypoint, instead of via the position of the nearest waypoint.
• Remove Waypoint from Route, but don't delete it.
• Delete Waypoint from Route.
• Mark/WP Properties. This is the only way to get to these properties, for the moment. The are not yet available in the Route manager. The dialog is the same as for an individual mark

Ship Track

Toggling  the track icon   turns tracking on and off. Tracking means that a record is kept of the vessels position as it proceeds. A trail is left behind the vessel. To display the tracking icon tick the box Toolbox->Etc->Show Track Icon. Below the "Show Track icon" check box there are a few more options related to track recording described here:  opencpn.org/ocpn/toolbox#etc



Recorded tracks can be imported, exported and managed using the The Route Manager and Data Import/Export.

When right clicking on a track you can select Track Properties from the menu, and a new dialog pops up. The same thing can be achieved through the Route Manager. A record of all the trackpoint will be listed. Below we can see a trackpoint entry every minute, due to the selection of a trackpoint every 60 seconds. Above, the selection is a trackpoint every 0.2 miles. Click on either a "Leg" or "To a Waypoint" item and a blue square will mark the position on the track.
From the right click menu the Delete track option is available as well. To prevent mistakes a confirmation dialog pops up.
For more about Tracks read about the Route Managers Track Tab in The Route Manager and Data Import/Export.



As a backup, a logbook entry is made every halfhour in the OpenCPN logfile. The format is similar to this:

14:30:00 CEST: LOGBOOK:  2011-06-28 12:30:00 UTC  DR Lat   44.43657 Lon  -65.17280

Man Over Board

Toolbox Settings

Click this icon to open the Tool Box which has the following tabs.

The Settings Tab

Show Status Bar: The status bar at the bottom of the display contains a lot of navigation information. If you have this info available elsewhere, turning this setting off increases the available space for the chart.

Show Printing Icon: When you need to print Chartlets

Enable Char Quilting: Chart Quilting.

Disable Full Screen Quilting: By default all visible charts of an appropriate scale are used in the quilt. With this box checked only charts that overlap the center of the screen are used in the quilt. Checking this box is easier on the system and may give a performance boost in certain circumstances.

Course Up Mode: Auto Follow and Display Orientation.

Lookahead Mode: Auto Follow and Display Orientation.

Show Chart Outlines: The borders of the available charts are shown. Vector charts are green, raster charts are red, and on CM93 available larger scale charts are purple. The CM93 chart outlines are not on if using quilting mode. As a safety precaution, the outlines of isolated dangers with large scale charts available, are shown in CM93 even if "Show Chart Outlines" is off, provided that quilting is not used and the scale is large enough. At a scale of 1:200.000 or larger these isolated Islands and dangers will be shown. Hence it is recommended not to use quilting in CM93 when on a longer passage.  More on cm93.

Show Grid: Activate a latitude and longitude layer on the display. This feature only works if the display is in North Up mode. The grid is handy on vector charts, that normally lacks this feature. 

Show Depth Units: Shows the charts depth units on the screen in embossed letters in the upper right corner. When in quilt mode, depth units are only shown if all charts in the quilt has the same depth unit.

Show skewed raster charts as North-up: Skewed chart are normally shown as intended by the cartographer, "Chart up". With this option they are rotated to show North-Up. If you are looking for speed, don't tick this box. I slows down the screen rendering .  Skewed charts are a common feature along the US Intercoastal Waterway.  More here: Auto Follow and Display Orientation

Use OpenGL  Read the OpenGL page!

Enable Smooth Panning/Zooming  This works best together with OpenGL. Test to see how it works with your graphic card. If you are using OpenGL, tick this box as well. This feature will not work if Toolbox->Etc->"Enable wheel-zoom-to-cursor" is activated.

OwnShip COG arrow predictor.....: Shows a red dashed line in front of your own boat, with present COG and ends in a small square, which represents where you will be in the set number of minutes, with the present speed. 6 minutes is a good starting value. If your vessel has a SOG of 10 knots the dashed line will be 1 nautical mile long.
If a heading sensor is available in the nmea data stream, and differs from COG, this is shown as a finer line with shorter dashes endiing in an open smal circle.



Harmonic dataset to use: Which tidal data to use. See Tides and Currents.

 

The GPS Tab:

NMEA Data Source: Set the source for your GPS connection. Note that you can write in this field. For example to get "Gippy" to work with OpenCPN, this is where you write the path to the virtual GPS created by Gippy. Similar, if you know that the GPS is on COM3, but this port does not show up in the list, just write "COM3" in the field.

Details for windows.
Due to performance reason OpenCPN by default only accepts COM ports up to 32. If this is not enough, OpenCPN will accept ports up to 42 with the following line added to the opencpn.ini configuration file:
[Settings]
WindowsComPortMax=42
In the tab select the 'NMEA Data Source' from the choices shown in the drop-down box, and choose the port to which your GPS is connected. If you are using a standard serial port, then choose the proper physical port number to match. If, on the other hand, you are using a USB GPS, then you will select the virtual serial port which was created by your GPS device driver. You may need to try several selections to find the correct port. For XP/Vista: Using the Device Manager, look for a serial port which appears and disappears dynamically as you plug and unplug the USB GPS cable. This is your virtual GPS serial port. When the properly configured GPS is connected, powered up, and recognized, and a show a green  icon or gps status icon  in the right end of the tool-bar. OpenCPN automatically configures  bits, parity, etc. These do not need to be separately specified.

Details for Linux. Connect directly to one of the available physical ports, or use gpsd. For gpsd versions earlier than 2.9, select "Network GPSD" else select "Network LIBGPS". For Ubuntu 10.4 and later select "Network LIBGPS".

GPSD Data Server: is normally "localhost", but it's possible to have one gpsd server on a local network with many OpenCPN clients. In this case, specify the network address of the gpsd server. With OpenCPN it's possible to connect even a Windows instance, to a gpsd server this way.

NMEA Baude Rate: 4800 is the normal value for many devices, but some newer gps receivers require a different value. Check your documentation.

Use Garmin GRMN/GRMN(Host) mode for Waypoint and Route uploads. Make sure that  this box is ticked, if you have a Garmin GPS. The reason for this is that Garmin units cannot accept route uploads via standard NMEA0183. This is a "design feature" of all Garmin receivers.

Show GPS/NMEA data stream window: If you check this box you will get a window that shows the NMEA data sentences coming into OpenCPN.
If gpsd is used on Linux, no data will be shown.
For simple NMEA data stream debugging, add the following to your opencpn.ini file:Under [Settings] add a line
DebugNMEA=1500
This will provide up to 1500 debug messages pertaining to NMEA traffic to the opencpn.log

Filter NMEA Course and Speed Data: Providing a rolling average of COG/SOG, with configurable sampling period. This feature is useful, for example, if you find that course and speed from the gps is varying erratically due to the sea state. The Dashboard plugin is not affected by this setting  - COG and SOG are updated about once per second.

Course-Up Mode Display Update Period: This relates to how often the entire displayed chart is updated. The own-ship and AIS icons are still updated every second. The default value is 15 seconds.

Autopilot Output Port: Connect any NMEA  0183 compatible autopilot. Select the correct serial port from the list. OpenCPN does accept autopilot output on the main GPS input port, using the same baud rate, unless it is set to "AIS Port (Shared)".
If you need the NMEA RMC sentence output on your autopilot port, add the following in the opencpn.ini file, called opencpn.conf in Linux:
..........
[Settings]
AutoPilot NMEA Sentence Out=RMB;RMC
..........
Default is RMB only, and works for most autopilots.
Most users will not need this config entry.
 

The Chart Tab

This is treated in detail in Installing Charts

Vector Charts Tab

More about vector-charts Vector Charts.

The AIS Tab

More about AIS.

The Language and Font Tab

 Languages: The following languages are available in OpenCPN 2.7 :
Brazilian Portuguese
Catalan
Chinese, Traditional
Czech
Danish
Dutch
English
Estonian
Finnish
French
Galician
German
Greek
Hungarian
Italian
Norwegian Bokmaal
Polish
Portuguese
Russian
Spanish
Swedish
Turkish
Choose your language here. Make sure your selected language has the support files installed on your computer (Linux). Default language is US English.

Remark: Changing the language will reset the font settings.

Font Options. Fonts can be selected for some elements on the display. Selecting the right size of font can have a dramatic impact on how values are presented. It's well worth playing around with these settings if you think that something is difficult to read for example.


 


The result of adjusting the "Console Value" font size.
 

 The Etc. Tab

The Plugin Tab

The Plugin tab is treated on these pages
Plugins
Dashboard Plugin
GRIB Weather Plugin

Night Navigation

Dimming the whole screen for Nighttime Navigation.

Change Color Scheme

Hot Keys

• Left clicking on a chart, centers the chart on that point.
• Double clicking a vector chart, displays all info for that point.
• Right clicking on any chart, access a context sensitive menu.
• Arrow Keys. Moves the chart view
• Alt + Arrow Keys. Moves the chart view in very small steps.
• +  Zoom In
• -  Zoom Out
• Ctrl + Z or Ctrl + for fine scale zooming in.
• Ctrl + X  or Ctrl - for fine scale zooming out.
• Ctrl + scroll wheel, zooming in/out in small steps.
• Ctrl + G cycles through (monochromatic) green, red and normal screen.
• Ctrl + M, drops a mark at the cursors position.
• Enter, also called Return, drops a mark at the cursors position.
• Esc ends the process of  route creation.
• F2 Toggle Auto Follow on / off
• F3 or Ctrl + S Show / hide ENC Text
• F4 Starts the measure tool. Escape : Stops it.
• F5 Toggle Daylight, Dusk and Night mode, if it is built into the Chart.
• F6 General Dimming, in steps, of the entire Screen.
• SHIFT + F6 reverses the dimming.
• F7 or Ctrl + Left-Arrow     Larger Scale Chart (Scale In)
• F8 or Ctrl + Right-Arrow   Smaller Scale Chart (Scale Out)
• F9  Chart Quilting on / off
• F11 Toggle Full Screen view.
• F12 or Ctrl + O Show / hide Chart Outlines
• Ctrl + L-Arrow or F7 Larger Scale Chart (Scale In)      
• Ctrl + M Drop Marker at current cursor position.
• Ctrl + O or F12 Show / hide Chart Outlines
• Ctrl + Q Quits OpenCPN
• Ctrl + R-Arrow or F8 Smaller Scale Chart (Scale Out)
• Ctrl + S or F3 Show / hide ENC Text
• Ctrl + space Man Over Board, sets MOB Marker at current GPS position.

AIS

For a general introduction to AIS Wikipedia is a good place to start.
The screendump below gives you a first feel for how AIS targets are presented and used in OpenCPN.



The Lookahead mode is activated here and our own vessel is proceeding 352 deg at 13 kts, leaving an activated track behind, and projecting a dashed line ahead representing the course. This ends in a dot, that represents where we will be in 6 minutes, or 1.3 nautical miles ahead. We are meeting a vessel, steaming in the opposite direction following the traffic separation. This target also has a line and a dot in-front of it representing course and where it will be in 6 minutes(user configurable). The two blue dots with a red/yellow line between them, represents where the vessels will be at CPA - closest point of approach, or when the are nearest each other, with present courses and speeds. The meeting vessel is red, as it is a potential danger to us.

A lot of information about the vessels that transmits AIS signals and are displayed on the chart, is available.
 

The cursor is on top of the the meeting vessel on a SW course. As we have not yet received full information, this can take a while, we don't get the name but an id number, the so called MMSI number, instead. Exactly what is shown in the yellow popup is configured in the AIS tabs Rollover heading.

This vessel is identified by name, and has a green color, as it does not represent any danger to our navigation.

If we instead of just hovering the cursor on an object, right click, the menu item AIS Target Query brings up the dialog above. A lot of relevant information is displayed. TCPA is the time until CPA, how long before we are at the closest point to the other vessel.

 
All the bells and whistles are activated! A new target appears behind an island on our port bow, OpenCPN sounds an alarm and draws a jagged circle around the new target. An AIS alert box with all the information about the new target pops up. We can silence the noise but, has to acknowledge before the box disappears.

The AIS Target List

The ToolBox AIS Tab

This tab controls the behavior of many thing in the AIS display. There are no "best" settings. It all depend on where you are, what kind of navigation you are into and what kind of vessel you are on. It is your responsibility to evaluate this.

AIS data port: Select your AIS input port on your computer. When this is set to anything but "None", the AIS button appears in the ToolBar. This button appears different according to the following conditions.
 

AIS Alive. The default AIS button. This icon appears as soon as an AIS port is active in the tool-box. It is also the normal state with an AIS receiver working and with no targets of interest.

AIS Alive and Activity, a small green circle will illuminate in the lower right corner of the Ais buton. If there is at least one AIS message every 4 seconds, the light will remain illuminated.

AIS Suppressed. This icon indicates only that target suppression is activated in the AIS tab in the ToolBox. Referring to the picture above there are two sort of suppression:
* Suppress display of all moored/anchored targets, max speed specified in dialog.
* Suppress Alerts for moored/anchored targets.
This icon will be over-ridden with the AIS alarm button if an alarm is, or becomes, active according to the AIS tab alarms settings in the toolbox.

AIS Alarm. A target exist that raises the alarm as defined in the AIS tab in the ToolBox. It is the three settings "CPA Calculations", that rules if and when an alarm is raised.

AIS Disabled. No targets, if available, are shown on the screen. This button toggles with the other buttons. For example, if the AIS alarm button is visible, click the button and it will change to the "AIS Disabled" button, and all targets, alarms etc, disappears from the display. Click again and the original button and AIS display comes back.

CPA calculation: Rules for how and when the Closest Point of Approach- CPA (when two vessels are nearest each other) is calculated. There are three tick boxes, which can be activated with user set values.
1. If the vessel is far away it is less interesting to calculate CPA. In a busy waterway this could cut down on clutter and processing speed if a reasonable value is set.
2. Similar arguments to No 1. This controls when a warning for minimum CPA distance is given.
3. Similar to No 2 this controls the alarm based on a minimum time to CPA. A target is regarded as lost if regular transmissions is not received, updating the vessels status.

Lost Targets: Rules for how lost targets should be handled on the display.
1. Target is regarded as lost if no transmission are received for the number of minutes set here, the target will change on the display and have a black bar across.
2. The lost target will be removed from the display after the number of minutes set here.

Display: If and how a vessels course and speed should be displayed and if stationary vessels should be on the screen.
1. An arrow will be shown in front of the vessel representing it's COG (Course Over Ground). The length of this arrow and the dot at the end of it represents the calculated position in the number of minutes set here. Set easily calculated values. If a vessel approaches you doing 15 kts and the time is set to 6 minutes, the dot will be 1.5 nautical miles ahead of the vessel.
2. A track will be shown behind a target. This helps to judge the target vessels intentions.



3. An anchored or moored target   will not be displayed if the speed is less than the value set here. This "avigational Staus" is set by the ships and may not be correct.
4. Show Area Notices. More about AIS messages here.

Rollover: Tick the boxes for the kind of information shown when hovering with the cursor over a target. This is what you get with all the settings  ticked.

CPA/TCPA Alerts: When an alert is triggered, a jagged circle in red is drawn around the target that set off the alarm. Additional events can be set here, drawing more attention to the alarm. For practical navigation, make sure your alarm sound is set.
1. Shows an alert dialog on the screen with target information when an alarm is triggered.
2. Sounds an alarm when an alarm is triggered.
3. Don't show alarms for anchored and moored targets.

Select Alert Sound. Select an alarm that suits you. This alarm will also be used if an anchor watch is set. Due to copyright issues, only a few sound files are included. Users can add their own generic ".wav" sound files. The location for these files are  "/usr/local/share/opencpn/sounds/" on Linux and typically C:\Program Files\OpenCPN\sounds on Windows XP.
Test Alert Sound. Test the selected sound and make sure this important feature is working

Enable Target Alert Acknowledge timeout. Once a target alert is acknowledged, wait the set number of minutes before the alert comes up again (if still applicable).

.

When exactly is an alarm activated?

An alert is set off if your boat is approaching the CPA, the blue dot on the extension of the course line, and the previously discussed set of conditions are met. Once the distance to the CPA increases, this happens when the involved vessels has passed each other, the alarm stops, even if the other conditions still apply. 

+++

Quick Reference for targets:
Note that AIS targets reporting position unavailable will be rendered in grey colour.

An active AIS SART and is a distress call equal to a "Mayday" transmission.
More about SART on this page.

Icon displayed when testing an AIS-SART device.

Potential Danger.

No Danger. Not Identified (Name not received)

No Danger. Identified

Lost Target

Ship which has lost fix - position unavailable not. Displayed at the last known position.

Anchored or moored. Displayed when the transmitted "Navigation status" is "at anchor". There is no guarantee that this status is correct, as it is set manually on the transmitting ship...

...illustrated by this ship. Note the black line on the yellow circle. This indicate that the vessel is turning to port (left), also illustrated by the lag in the display update. ROT - Rate Of Turn is available in the "Ais Target Query" dialog, through the right click menu.

The V-shape stern indicates a Class B target. Tugboats and pilot boats very often carry Class B transponders. These are often designed specifically for small commercial boats, fishing boats and pleasure crafts.

This blue bit is the European, Inland AIS standard, "Blue Flag" signal, commonly seen on inland waters to indicate that the vessel requests a "stbd-stbd" passage or crossing. This Blue Signal is manually switched on/off on the target.

Aton, Aid to Navigation, for example a Lighthouse or a Buoy with an AIS transmitter.  

Aton, Aid to Navigation, that is off it's suposed position. For example a buoy equiped with AIS that has come adrift.

Virtual Aton, Virtual Aid to Navigation, not a real marker. Can be useful for a range of situations.


AIS Base Statio

The following tagets only displays if DSC messages and GpsGate mesages are mixed in to the incomming AIS stream, by using, for example a multiplexer. More on next page.

DSC Station

DSC Station transmitting a distress signal. Treat this as a "Mayday" call.

GpsGate Buddy target.



 

AIS SART

The US FCC has recently approved transmissions by AIS SART devices.  These devices were originally designed for SOLAS class ships as an alternative to radar SARTs for carriage on life boats, but the efficiency of design has encouraged applications down to man-over-board devices. (www.exactearth.com/media-centre/exactblog,May 3, 2012)

Search And Rescue Transponders (SART) or an EPIRB, transmitting AIS messages are now available on the market. In an emergency situation the position  will be displayed as an AIS target in  OpenCPN. AIS SART can be a device on a vessel, in a life raft or a personal Man Over Board (MOB) device. The common thing is that the icon below marks an emergency.

SART icon, distress target display. This is a "Mayday".

On OpenCPN a distress signal sent by a  SART, triggers an visual alert and a warning sound, if this is activated in the ToolBox-->AIS Tab.  



Once the alert is "Acknowledged", the target behaves as any other AIS target. In the picture below the cursor is over the target.



And here is an AIS target query.



AIS SART messages and DSC distress calls are always found at the top of the AIS target list.



Testing
It is possible to test a SART, to make sure it works.

Icon displayed when testing an AIS-SART device.

DSC and Buddy via AIS.

This feature expects the DSC and GPSGate Buddy messages to be mulitplexed into the AIS stream.

Quick Reference.

DSC Station

DSC Station transmitting a distress signal. This is a "Mayday".

GpsGate Buddy target.




A normal DSC tarket, is someone using a dsc-capable VHF



Distress message via DSC, Digital selective Calling, from an unidentyfied AIS target.



A green Buddy target on an island.



The AIS Target List View

AIS Area Messages

To display the messages, tick the Toolbox->AIS->Show area notices(from AIS binary messages).

Many countries around the maritime world are testing the AIS binary messages. Expect a lot of development in this area.

In OpenCPN, this is very much a work in progress, only added in late April 2012. For more details read www.cruisersforum.com/forums/f134/beta-test-technical-30929-56.html#post937274.

Areas are displayed but not the messages.
In the US, Cape Cod is transmitting experimental Right Whale information. For testing, copy vislab-ccom.unh.edu/ais/notices.aivdm into a text file and point the VDR (Voyage Data Recording) plugin to this file.
This message is updated quite often.

Extended Marks

The Route Manager and Data Import/Export

• Through the Route Manager  OpenCPN can save and load waypoints, routes, tracks and layers using the GPX transfer format.
• This lets you save your routes and marks so you can have more than the active ones - for example to do route planning, or archive existing data.
• GPX format is supported by a wide variety of programs.

• You can have as many saved files as you wish, there are no limits on the number of saved files.
• Use this for passage planning by saving multiple possible routes for a passage.
• Save routes and tracks for historical/log purposes.
• Prepare layers as an aid to navigation en route.
• All Navigation Objects on this page, except for "Temporary Layers", are persistent between sessions. More here:Navigation Data Backup
• All objects visibility is toggled by clicking the "eye", or other icon, to the left of the route/track/waypoint name on each line.
• All objets can be sorted by the header in the columns in the Manager. By clicking "Route Name below, the routes will be sorted alphabetically, pressing once again reverses the order. Similar for the column "To", the destination.
  
  

  Routes

  
  
• Click the "eye" to the far left on the line with the route to toggle if the route is displayed or hidden on the chart.
• To Sort routes click "Route Name" or "To"
• Properties:This button brings up a new dialog with settings that can be changed for each route.
• 
• Departure Time:With no departure time the ETE (Estimated Time Enroute) is calculated. Enter a Departure Time and the ETA will be calculated
• Times shown as: UTC is a new name for GMT. LMT is a local mean time based on the present longitude. For Local Zone Time one can also enter the keyword "now".
• Color: Set the displayed color of the track or keep the default.
  
• Style: Solid, dashes, dots, a combination or keep the default.
• Width: Set the width of the track or keep or keep the default.
• Marking a  line with the leg number and the destination Waypoint in the Properties Dialog also marks the Waypoint on the chart with a blue square.
• Extend Route:Extending is possible only when it is obvious, what should be joined with the current route (current = visible in the Dialog). Eligible are all visible route points shared with, or lying nearby to the current route's endpoint. If there is exactly 1 such point, then it is considered obvious, and the Extend button is enabled. If there are more, some should be hidden before proceeding, until just 1 remains.
  Routes are extended  forward, based on the geographic location, next route point must be very near, as when mouse-extending the route. If the next route point is to far away for extending, just create the joining leg and extend twice.
• Split Route:For splitting, the split point is selected as the row in the listing. The point-of-split becomes part of both new routes (shared) or tracks (cloned). Original route/track is deleted.
• Here is a basic example of first splitting then extending. The test route is shown below
• "Split Test_A"
• In the Route Managers property dialog for the route we have selected a waypoint where we would like to split the route. The "Split Test" Route now consists of two parts, that has been renamed.
• 
• Next we extend the first leg "Split Test_A" with the second leg "Split Test_B". This extended route s now named "Split Test_B_plus.
• 
• Activate/Deactivate: Activates/Deactivates a route marked in the left part of the window.
• Zoom to: Zooms in on a route marked in the left part of the window.
• Reverse: Reverses a selected route.
• Delete: Deletes selected route or track.
• Export Route: Save the route on your computer for later use (import)
• Send to GPS. Send the Route to your GPS. For Garmin Users, make sure that the ToolBox->GPS->"Use Garmin GRMN/GRMN(Host) mode for Waypoint and Route uploads" box is ticked. The reason for this is that Garmin units cannot accept route uploads via NMEA0183. This is a "design feature" of all Garmin receivers.
• Delete All. Be careful. If you know you have saved the routes on your computer and are able to import the again, this is a simple way to clear the screen from routes. Better be safe than sorry, so save before deleting, if you want to be able to use the routes again.
• Import. Import one or more previously saved Routes. It is possible to select and import multiple routes.

• Export All Routes. Saves all routes in one gpx file. This is done through a normal file saving dialog.



Route Planning



• If a Tidal Height Curve Dialog, for an individual tidal station is  shown on the screen, the tidal situation for this station will be tabulated along all route points in the route properties dialog. It is essential to enter a departure time and a planned speed. Once "Enter" is pressed the tidal column will show the nearest High or Low water considering the ETA at each waypoint.
   
   
• The ">" (meaning: "Now") departure time specification can be entered if local PC time zone is selected. It differs from specifying the same moment of time, but without the "Now" spec (e.g. "5/23/2011 08:00" vs. ">"):
   - "5/23/2011 08:00" - calculates departure at 0800 on May 23rd 2011 from the first waypoint of the route
   - ">" - issued at 0800 on May 23rd 2011 - calculates departure Now from the current boat position, including the distance to the first waypoint of the route
• If no tide dialog for any station is open and a waypoints name contains the string @~~<name>, for example "@~~York Spit Light", then the tide report for the closest station with matching name is shown in the tide column for this waypoint. The most appropriate tidal station for each waypoint can thus be selected.
• When entering a departure time the ETA, Expected Time of Arrival will be shown, instead of ETE, Expected Time En-route.
• The individual waypoints "Description" field can contain the setting of planned speed specific just to the next route leg (e.g. "VMG=4.5;") and/or the specification of Estimated Time of Departure from this waypoint (e.g. " ETD=2/14/2011 12:00;"), allowing for planning extended stopovers. Time can be specified as UT, LMT or local zone time at the PC (default).
   

 

Tracks



• Make sure that you have read all about Automatic Daily tracks and track Highlighting in the Documentation for the Toolbox etc tab
• The visibility of tracks is controlled by clicking the "eye" on each line. Tracks can be sorted by clicking the column headers.




• Start Track. Same thing as pressing the track button in the ToolBar
• Route from Track. Make a route from a track, for future use. The new route is listed in the Route Manager tab. An smart algorithm is used to create  route of reasonable size. Look upon this as a suggestion to a route, that needs manual editing. It is a tool that can be used as a first step in regular route construction.
• All other buttons behaves similar to corresponding buttons for Routes. The color of the tracks can be changed.
• 
• Tracks are extended backward, based on the time-stamp sequence, a track is selected, which ends as the latest one before the start of current track. Tracks are extended as a single segment if they share the extending point, otherwise a new, disjoint segment is added. Joining 2 tracks (i.e. extending a track) results in just 1 track remaining. 


Waypoints






• Control the visibility of each waypoint by clicking the waypoint icon to the left on each line. Sort the waypoints by clicking the column headers.
• New. Create a new waypoint. This brings up the properties dialog.
• Properties. All about the dialog on this page.
• Zoom to centers the chart display on the waypoint.
• Go To. Makes an instant route from present position to the mark and activates the route. A similar instant route is created by right clicking and selecting "Go To Here" without first creating a mark. This instant route will be listed in the Route Tab.
• Export Wpt and Send to GPS buttons behaves similar to corresponding buttons for Routes.
• Delete All, does not delete any Man Over Board marks. All otther marks are deleted.

Layers

• Layers are one or more routes, tracks or waypoints  that has been saved together in a gpx file. A layer is represented as a single gpx file. A layer is persistent and protected from changes. A waypoint in a gpx file for example, can be imported either as a "waypoint" or as a layer. The difference is that when imported as a layer it cannot be changed or deleted. To see if a waypoint, route or track, is a part of a layer, open properties and check the top of the dialog. If it is a part of layer, it will say so.
  

   

  
  

   

  

 

• Layers are useful for many things. It can for example be used to update charts with new navigation marks and dangers as per Notices to Mariners, and to add Radio Call-In Points or to build a database of lights and locations, that will be visible on chart regardless of current scale. See the first picture above. In the second picture, a very good celestial fix, plotted with a gpx script has been saved as a layer.
• More advanced uses could for example be an interactive cruising guide using the possibility to embed links in waypoint descriptions.
• Layers can be created in OpenCPN,  and saved as a gpxfile, or be created offline, manually or by scripts, for example.
• Layers that are saved in a directory called "layers", in the same place that holds your opencpn.ini(config) file, are automatically loaded on start of OpenCPN.
  Easiest way to find this is to go to the - button in the ToolBar and look all the way down in the first tab (About).
  In Linux create the directory: /home/$USER/.opencpn/layers.
• Any subdirectory in the layers directory,  is also loaded. To actually display these layers on startup, tick the box towards the bottom of the TooBox Etc tab - "Show layers initially".
• Layers worth keeping, could be kept in the mentioned "layers" directory and  visibility during a session can be handled through "Hide from Chart" or "Show on Chart" buttons. New layers, gpx files, can easily be added in a subdirectory of it's own.
• A few restrictions apply to layer marks. A layer mark cannot be used to set anchor-watch on. If right-click-selecting co-located objects, priority is given to non-layer objects.
• Temporary layer: Any gpx file can be imported as a layer. This can be used for developing layers or for import from a user defined directory with predefined layers, as necessary. Layers imported this way will not be saved when closing down the computer, but can of course be loaded again. More permanent layers should be kept in the "layers" directory, as described above.
• Delete: Unloads the layer, but doesn't of course touch the originally imported gpx file.
• Hide from Chart or Show on Chart Controls if the marked layer is visible. The same thing can be achieved by clicking the "eye" to the left of the layers name.
• Hide WPT Names Shows a visible layer without waypoint names. This helps to unclutter layers, when zoomed out.
• List contents or Delist Contents  Listing is this context means showing the individual points in the layer as waypoints in the "Waypoints Tab"
• Import GPX.. and Export All.. Warning these buttons has nothing to do with Layers. They work as if you are in an other tab. For import use "Import New Layers". For export, create layers as described above.

Using Routes

To include existing waypoints in a route

How to use split and extend - an example.



Hm...a bit of a miss in the planning. An islet with a shallow bank extending southward on our route. We put two marks north of the obstruction and would like to include these in our route.



The waypoint west of the islet is #2. We mark this in "Route Properties", from the right-click menu. The Button "Split Route" is highlighted, meaning it is available to use. This is exactly what we want to do, so we click the button and split the route at wpt #2.




Right click at #2 and choose "Append Waypoint",



Move the cursor to the first triangle, and answer yes to "Use nearby waypoint?".
Then move the cursor to the second triangle , and answer yes to "Use nearby waypoint?".
Same thing for the original wpt to the east of the islet.



Click "Activate Route" to see that this extension worked.



Once again mark "Route Properties" in the right-click dialog. #3 is the last wpt in our "new" temporary route. The "Extend Route" button is highlighted, so we click it.




Open the Route Manager to view the result. Notice the naming of the routes. _B_plus is active. What remains is to delete route _B and to rename _B_plus to a suitable name, for example the name of your original route.



Deleting route _B.



And here is the finally adjusted route.

This was just an exercise.....in real life, it would be easier to just move the existing waypoints in the route, to avoid the Islet.

Planning Data

The examples shown on this page are all suitable for import as layers, as that will prevent any waypoint from being moved by mistake.

Creating and Importing Great Circle Routes

GPX import can be used for many things, three sample applications follows below. First, look at this picture. Planning a trip from Cape Town to Freemantle ?

Here you have two imported routes, the Southern route is a pure Great Circle, the middle route is a Composite Great Circle, and then the normal Rhumb Line furthest to the north.
A Great Circle is the shortest distance between two point on the globe. A composite route is the same thing with the additional condition to stay below a limiting latitude, in this case 39°30'S. A rhumb line is a straight line on a Mercator chart. The Mercator projection is the standard for OpenCPN.

Let us compare the distances involved.

• The pure great circle is 4610 nautical miles (M)
• The great circle as plotted with 5° of longitude between the waypoints is 4627 M
• The pure composite route, limited by latitude 39°30’ S is 4651M
• The composite route as plotted with 3° of longitude between waypoints (for the great circles) is 4669 M.
• The rhumb line is 4843 M.

So the advantage of a great circle is obvious. The disadvantages, in this case are many.
Colder weather, stronger winds, higher seas and perhaps even icebergs. The great circle is just one factor in the decision making when planning a route, the weather is likely to be the deciding factor in most cases.

A great circle route  is created with  the "gc" Ruby script, that is cross platform.
To create a gpx file containing a great circle you have to enter the departure points lat & long, followed by the destination points lat & long and the optionally a limiting latitude for composite sailing and the distance in long between waypoints, default is set to 5°.

Need to see some offshore weather observations?

NOAAs  NDBC site gives access to a lot of offshore observations from buoys and ships worldwide.
To easy visualize all this data the "ShipWxRep" script transform a limited set of all the available data into gpx waypoints. The format, as seen above is "wind direction, wind speed, time for observation, and air pressure". This can be helpful when evaluating the accuracy of grib files, even though the best tool in this respect probably is a calibrated digital barometer.

Plotting Miami Tropical Forecast Advisories.

If you only have access to low bandwidth Internet, this script is a way to quickly plot the contents of, for example an email, containing the forecast advisory. In any case, it is a good idea to have the forecast track of a tropical system available where you normally do your navigation and planning.



Download the gpx scripts here. For some help run each script without arguments.

CM93 Offsets

• Go to single chart (i.e. non-quilted) mode, with cm93 charts displayed. Use F9 to flip quilting on and off
• Zoom/Pan to the region of interest.
• Right click and activate "CM93 Offset Dialog"

• In the list of cells/MCOVR IDs, selected the one MCOVR of interest. The coverage area for this MCOVR object will be outlined with a heavy yellow border.



• Some cells have built in corrections already applied. The values wgsox and wgsoy, are offsets to bring the original chart cell to WGS84. See the first and third cell in the picture above. The values are for information only, and cannot be changed. These corrections are generally correct, but not always. Sometimes the corrections are wrong and sometimes there are no corrections where there ought to be. This is where this manual offset feature comes in handy.

• Use the spin controls on the right side of the dialog to adjust the desired user offsets. It is also possible to write numbers directly. Notice that positive corrections is towards North and East.
• In some cases it is not clear exactly which M_COVR ID that represents your position. A simple test will reveal if a mark reacts to (large) corrections.
• The offsets are automatically saved in the binary MCOVR cache files found in the program data directory as CM93/...

Anchor Watch

Automatic Anchor Mark

Navigation Data Backup

About Plugins

OpenCPN offers two default plugins available preinstalled:

• GRIB Weather Plugin
• Dashboard Plugin

And quite a few plugins on top of that:

• The WMM plugin showing magnetic variation.
• Logbook Konni, an advanced logbook.
• A logbook plugin. The Original logbook plugin
• A Chart downloader/updater plugin
• VDR or Voyage Data Recorder
• Google Earth plugin - Windows only.
• BSB4 plugin -Windows only - Non Free.
• "nv-charts" plugin. Windows only - Non Free.
• Kml overlay plugin.
• Hydrographic survey plugin.
• Radar overlay plugin.

Download Plugins

Installing a Plugin

Enabling a Plugin

GRIB Weather PlugIn

• To display grib files as an overlay on your normal charts you have to first activate the grib icon
• Go to find the plugin tab. Click on the Grib plugin, then the "Enable" button. The "Prefence" Button brings up a small dialog.
  

  

• Tick the "Show GRIB Icon" box. Tick the next box as well, unless you are on old hardware. Not ticking the "High Definition Graphics" box can help to speed up the grib display, in such cases.
• 
• The Next step is to click the icon, which brings up the Grib Display Control. Use the upper part of this window to navigate to, and select your grib files. The grib files will then be appear in the control. See picture above.
• Click on the ">" in front of the gribfile. The individual forecasts contained in the gribfile, is then displayed under the gribfile heading.
• Click on one of the forecasts and it will be displayed. When you move the cursor over the grib display, the values for wind etc will be displayed for the cursor position, in the lower part of the "Grib Display Control". Here you can select what grib values to view. Note that not all gribfiles contains wave data.
• When zoomed in to show just a small area of the chart, there may not be any wind-arrows visible. The relevant data will, however, still be displayed in the grib dialog. To see the wind arrows zoom out to view a larger area.
• The gribs are only displayed on the charts when the "Grib Display Control" dialog is open.
• For certain areas gribfiles describing currents are available
• OpenCPN will display most grib file formats, but as it is a fairly new feature, bug reports are very welcome.

What is a grib file?

• If you are not familiar with grib weather files, make sure you understand the basics, before you start to use them. It is essential to understand the limitations of weather forecasts in the grib format. It is also worth pointing out that gribs are not reliable near tropical systems, at least not when using gribs based on the very common GFS model.
• To get started with gribs and to find sources for downloads, check Franks-Weather.
• A very good book is David Burch: Modern Marine Weather, with a thorough treatment of the subject.
• A few files including lectures on  tropical weather and gribs are available here.
• ZyGrib is a free and open-source software(FOSS) dedicated grib viewer. Grib files can be downloaded by ZyGrib and then opened in OpenCPN.

The Dashboard PlugIn

The Dashboard Tab

The available instruments are:
Position (text)
SOG (text) -Speed Over Ground
Speedometer (dial)
COG(text) - Course Over Ground
Compass(dial)
STW(text) Speed Through Water
HDG(text) Heading
Apparent wind(dial)
Wind angle(dial)
Wind speed(text)
Wind speed(dial)
True Wind(dial)
Depth(text)

Delete. Highlight an entry in the Instrument Window to delete it.

Up / Down. Highlight an entry in the Instrument Window and change the order between the selected instruments. This order will also be the order between the instruments in the Dashboard dialog.

The Appearance Tab



Use this tab to set fonts.

These controls together enables the user to adjust the view of the dashboard to suit individual needs.


 

imgkap

Picture to Chart, some details

VER/2.0 [0]
BSB/NA= [1]
    NU=[2],RA=[3],[4],DU=72
KNP/SC=[5],GD=[6],PR=[7]
    PP=[8],PI=UNKNOWN,SP=UNKNOWN,SK=[8a],TA=[8b]
    UN=[9],SD=[10],DX=000,DY=000[11]
CED/SE=[12],RE=[13],ED=[14]
OST/1
REF/1,[16]
REF/2,
REF/3,
REF/4,
PLY/1,[17]
PLY/2,
PLY/3,
PLY/4,
DTM/0.00,0.00 [18]
CPH/0.0 [19]

0. The BSB version used
1. *Name of chart from the chart. Warning do not use commas ",".
2. *Chart number. Plan A on 23456 should be named 23456_A
3.  Size of picture Pixel x coordinate
4.  Size of picture Pixel y coordinate
5. *Scale of the chart from the chart.
6. *Geodetic datum, for example WGS84, from the chart. I not defined on the chart write "UNKNOWN" No guesswork, it is either stated, or said to be a local datum, that cannot be related to WGS84. Charts released earlier than 1990 (?) and conforming to
World Geodetic System should be WGS72, unless stated otherwise. The difference between WGS 84 and WGS 72 is minor.
7. *Projection, almost always MERCATOR, a few charts are TRANSVERSE MERCATOR. We should not bother with other projections, GNOMONIC small scale great circle charts etc. If we come across large scale plans with GNOMONIC projection this should be used, say
 1:50,000 or larger. High latitude "Lambert Conformal Conic Projection" should be skipped, for now. OpenCPN only handles Mercator and  Transversal Mercator. I don't think th Polyconic charts.
8. *For Mercator charts this is the latitude where the scale is valid. If available on the chart, use that value.
If it is not available on the chart use the average value of the latitude of the upper and lower edge, to the nearest 1/10 of a degree.
For Transverse Mercator charts use the average _longitude_  of the eastern and western edge.
Treat a possible large scale gnomonic as a Mercator chart.
8a. SK is the skew angle of charts that are not "North Up". For North Up the value is 0.0
8b.TA is he text angle, more or less always 90.0
9. Unit for soundings from the chart, mostly METERS
10. Datum for soundings from the chart, for ex MLWS, LAT
11. x and y resolution, meters per pixel. Not necessary for us to compute. OpenCPN andles this.
12. Chart edition date copied from the chart,inf in SW corner, except, there must be _no_ commas.
13. Our release edition.
14. Our release date.
16. Geo-referencing, standard case - simple 4 corner chart, use the 4 corners, starting in the SW corner proceeding clockwise.
Format: x pix,y pix, lat, long. Lat & long i decimal degrees, to 8 decimals, where N lat and E long are positive.
One reason to use all 4 corners is to catch  skewed and warped charts, and calculate SK (8a), also to calculate a rotating angle for charts that are not properly aligned.
17. Standard case, just copy the lat & long from the REFs.
18. Corrections in seconds of arc to bring the chart to WGS84. This is generally given on the chart(if they exist), in a format where the corrections are in minutes of arc for plotting a WGS84 position on the chart. This correction must be transformed to seconds of arc and the signs reversed.(we are doing the reverse to the case stated on the charts). These values are sometimes difficult to find on the chart.
19. If a chart  spans the 180th meridian = > CPH/180.0, else => CPH/0.0. So CPH/ is 0.0 for most charts. Note that OpenCPN handles transiting the 180:th meridian while a few other plotters don't.

**IFM** is not used as tif2bsb and imgkap calculates this value and ads it to the header on the final kap, together with other values such as RGB. Any manually entered values will be overwritten.

libBSB

LibBSB is an older alternative to imgkap, for converting chart pictures to usable BSB type charts.

Full documentation and source code is available at libbsb.sourceforge.net.

Only binary packages for Debian based Linux distros and Windows are available for download here.  There may be packages available for alternative operating systems elsewhere.

libbsb-tools_0.0.7_i386.deb

libbsb-tools_0.0.7_amd64.deb

libbsb-0.0.7-win32.zip

 

Conversion Using Linux

How to convert your chart images to a format that OpenCPN will read using Linux

Do you have a bunch of scanned charts of your area, in graphical format (jpg, tiff, etc.) and OpenCPN won't read them?
Here's how you can – with a bit of work, sure, but worth the effort – convert them into usable electronic charts.

The tools:

1. ImageMagick: http://www.imagemagick.org/ (Binary releases are available for a few distributions, for Ubuntu just get it with the package manager, it's in the repositories.)
2. Libbsb: http://libbsb.sourceforge.net (You will need some version of libtiff-dev and libpng-dev installed to build it. A .deb package that worked fine for me can be found here.
3. mc2bsbh: you can get it here.
   
   1. Get the c++ source file, and from its directory, type:
   2. g++ -Wall -s -O2 mc2bsbh.cpp -o mc2bsbh
   3. It compiled without any problem on my (very standard) Karmic. I personally put it in /usr/local/bin, which I own as user, so it's in the PATH and can be called from anywhere, if you leave it in the working directory, use ./mc2bsbh
4. MapCal: part of the free navigation package SeaClear .
   
   1. Note: I had some problems running it with Wine (saving the calibration) but I can't reproduce the error and now it works fine. One suggestion is, make the directory you're going to write the calibration in world-writable before running MapCal.
5. The pcx2tif script (optional) , found here.  This is a great little shell script by "taifun" used to convert old Maptech-style formats of tiled charts. If you find your chart is made of little bits instead of a whole file, this will stitch them all together in TIFF format.
   1. Instructions for use are in the tarball.

Once we have the tools all set up, we can get to work. The process in in five steps:

1. Convert a chart image to tiff with imagemagick.
2. Convert it again to png with the same (you'll need both files).
3. Load the png version of the chart in Mapcal and calibrate it.
4. Generate the chart header with mc2bsbh, and make the .kap version of the chart, with libbsb.
5. Copy the resulting .kap into opencpn's chart dir, and reload the chart database.

Let's see them in detail:

Steps 1 and 2:

Say you have a chart in jpeg format called chart.jpg.

From the command line, use:
 convert chart.jpg -colors 127 chart.gif

and then again,
 convert chart.gif -colors 127 chart.tif

and then again,
 convert chart.jpg -colors 127 chart.png

(there is a script that does this for multiple files, get it here , just remove the .doc extension, this is the example)
Throw away the .gif file. Don't ask me why you need to generate it in the first place, but apparently you do, it's an imagemagick thing. Keep the .tif and the .png ones a while longer, though. You'll be even happier to get rid of them when you've finished.

Step 3:

• Open MapCal.
• File, Open Image. Open the .png version of your chart. Ignore the data window for the moment, you'll do that later, click OK. You should see your chart.
• To calibrate it, choose a point near a corner for which it is easy to know lat/lon. Right-click on it, and choose Add New Cal. Point. To zoom in and out use the little + and – buttons at the bottom.
• Ignore the fact that Latitude has three integer figures, we're still talking about the Earth. Enter the coordinates and proceed for at least three more points, near the corners.
• Click Activate Changes. Check that the grid makes sense. Click Border, draw a border around the chart (that part is easy).
• You should also enter some data for the chart: Edit, Chart Information.
• The Chart Name will show up in OpenCPN to remind you of all your hard work, choose it well.
• For this example we'll just use “chart”.
• You should also enter at least Scale (found on the chart) Depth Units, Projection (Mercator most likely) and Datum (WGS84 most likely, but be careful with older charts). All of this information should be found on the chart itself.
• For more details, you have the SeaClear Manual.
• File, Save Calibration. Repeat ad-lib for any other charts and exit. If everything went well, you'll find a file called CHARTCAL.DIR in the same directory as you loaded your png chart from. This is used to (finally) make your calibrated chart that OpenCPN will use, as detailed in

Step 4:

• Generate the chart header from the command line:
  • mc2bsbh CHARTCAL.DIR
• You should see:
  
  • Create CHART.hdr
    (the .hdr file must have DOS newlines)
• So type:
  
  • tif2bsb -c 127 CHART.hdr chart.tif chart.kap
• At which point you should have a chart.kap file that OpenCPN will happily use.
  
  This can be done for many charts at a time by using the tif2bsb batch script from the mc2bsbh page. If it gives you any problem with lowercase-uppercase names, try: 
  for i in `find * -depth`; do (mv $i `echo $i|tr [:upper:] [:lower:]`); done
  which will convert all files in the current directory to lowercase (works great for me).
  If you get an error like /bin/bash^M, no such shell (I did), it's a cr/lf thing, just edit it, type [enter] at the end of each line (there's only 7) and get rid of the blank ones.
• Proceed to install the filename(s).kap into OpenCPN (see installing charts) 

Note 1: you can also make the .hdr file “manually”, using a template and entering the calibration data with a text editor, but I won't go into that for the moment.

Note 2 (about the commands, so if there's any problem you know what to look for) :

convert is a command from imagemagick.
tif2bsb is a command from libbsb.
mc2bsbh is a standalone thing.

Note 3: (by Jonasberg, on the colors in the conversions) :

The "127" is the number of individual colors used. Sometimes it pays of to reduce this number to get a smaller file size, say, if you start with a bitmapped format like png that contains fewer colors.

GNU GENERAL PUBLIC LICENSE

Alarm Sounds

Celestial Navigation

• Identification of celestial bodies.
• Nautical Almanac, including sun and moon phenomena.
• Sights: correction of the observed altitude and calculation of line of position (type of LoP: Marcq Saint Hilaire).
• Celestial Fix. GPX file output that serves as an input to OpenCPN. Complete solution: fix, circles of position, confidence ellipse.

Circles of position or Circles of equal altitude. General scale.


Fix and confidence ellipse. Coastal scale.

Pack overview
Software is available for free, for non-commercial use, at:

Chart Conversion

• bsb2tif - convert BSB image to TIFF format
• bsb2ppm - convert BSB image to PPM format
• bsb2png - convert BSB image to PNG format
• tif2bsb - convert TIFF image to BSB image
• ppm2bsb - convert PPM image to BSB image
• bsbfix - fix the index table in a BSB file

 
Port detail generated by GE2KAP

Chart Work

Using the GPX utility and the Chart Work program is it possible to do on an electronic nautical chart the work you do in a traditional way.

 

Chart Work - Traditional paper chart work on an ECS.

Coastal navigation

the three types of lines of position used are:

• Bearing
• Range
  
• Horizontal angle

Fix by three simultaneous bearings.

Fix by three simultaneous bearings. Detail.
 

Celestial navigation

Offshore navigators use celestial navigation,sextant observations, as a backup for the GPS. Use a sextant for taking the altitude of a celestial body and OpenCPN to plot the celestial circle of position instead the LoP -Line of Position-. Repeat this and take at least three sights. You easily can check if any danger is near your fix, and the uncertainty in your position.

Parameters of a circle of position in astronavigation.

•  Method explained

Route using the three types of sailings

• Rhumb Line. Direct with OpenCPN.
• Great Circle. (With Chart Work)
• Composite. (With Chart Work)

Composite Route.

Composite Route plot wiht OpenCPN.

• Manual of Chart WorK

• Example: pdf and GPX file

Free software to create the GPX file that serves as an input to OpenCPN is available at

http://sites.google.com/site/navigationalalgorithms/ (Only for Windows®)

GRIB Data and Software

Ugrib

zyGrib

NMEA Instruments

1. NavMonPC: Closed source, windows only, but reportedly excellent gauges for wind instruments, GPS, AIS display, anchor alarm, etc.
2. PolarCOM: Closed source, windows, linux, mac; visually appealing gauges for wind instruments, GPS, anchor alarm, etc.
3. CapCode: Free software, Java-based navigation programme with sailing/regatta focus, supports wind instruments, polars, VMG etc.
4. Matrix Mariner GPS: Free software, Window and Linux, visually appealing GPS display, some features for GPS handling including live gps output to Google Earth. (Windows version includes VSPE kernel mode virtual serial driver).
5. VSPE: Closed source freeware, windows only, Virtual Serial Port Emulator enables you to use data from one serialport (such as GPS or NMEA data) simultaneously with several programs. You can run PolarCom, NavMonPC, OpenCPN and other navigation programs at the same time without COMport conflict.
6. gpsview:Tool for analyse NMEA textual data, allows to load NMEA log files and view data in table, graph and track forms.

Tides

Official sources
1. France, SHOM - http://www.shom.fr/fr_page/fr_serv_prediction/ann_marees.htm
2. United Kingdom, easytide UKHO - http://easytide.ukho.gov.uk/EASYTIDE/EasyTide/SelectPort.aspx
3. United Kingdom, NOC - http://www.pol.ac.uk/ntslf/tidalp.html
4. The Netherlands, Min. V&W - http://live.getij.nl/index.cfm?page=getijvoorspellingen2 (including export functions)
5. The Netherlands, RWS - iCalendar Tide Wizard: http://live.getij.nl/outlookgadget/php/index.php?field_language=en
6. Germany, BSH - http://www.bsh.de/de/Meeresdaten/Vorhersagen/Gezeiten/index.jsp
7. United States, NOAA - http://tidesandcurrents.noaa.gov/gmap3/
8. Canada, CHS (pdf files) - http://www.marees.gc.ca/english/Pr%E9dic_PDF_2011_Ang.shtml
9. Canada, CHS - http://www.marees.gc.ca/cgi-bin/tide-shc.cgi?queryType=showFrameset&zone=1&language=english&region=4&stnnum=3250
10.  ... and links for Canada (broken!), Denmark, France, Israël, New Zealand, Portugal and Spain are shown here:
         http://live.getij.nl/index.cfm?page=links&linkcat=4

Not for navigation!
XTide -  Harmonic tide clock and tide predictor. Work with X-windows, plain text terminals, or the web.
http://www.flaterco.com/xtide/

WXTide32 - a free Windows tide and current prediction program.
http://www.wxtide32.com/

WXTides Stations - tcdata, (HARMONIC, HARMONIC.IDX), for OpenCPN
http://fserv.skill-club.com/get_1088_156a.html

cTide: tide prediction software for PocketPC's
http://airtaxi.net/ctide/

JTides - an advanced, accurate, easy-to-use tide and current prediction Java MDI (Multi-Document Interface) application.
http://www.arachnoid.com/JTides/

QuickTide - a free Windows tide program specifically made for The Netherlands, especially for the tidal area of the Waddenzee. For Linux: runs under Wine. In Dutch only.
http://www.quicktide.nl/

Magnetic compass

• Magnetic Variation - or magnetic declination is the angle between magnetic north and true north.
• Deviation curve of magnetic compass - Magnetic deviation is the error induced in a compass by local magnetic fields.

Deviation curve of magnetic compass

An analytic method for obtaining the deviation curve of a magnetic compass allowing obtaining the value of the deviation for any course.

• Method explained
• free software

Magnetic Variation

Magnetic variation, or magnetic declination, is shown on paper and raster charts, but can also be calculated using the World Magnetic Model. C source code for any platform is available at: http://www.ngdc.noaa.gov/geomag/WMM/soft.shtml

For Windows OS, compilations with a graphical user interface (GUI) are available at:

1. http://www.ngdc.noaa.gov/geomag/WMM/wmm_gdownload.shtml and at
2. http://sites.google.com/site/navigationalalgorithms/

A World Magnetic Data PlugIn is available for OpenCPN since 2011.04.03 (version 0.1) at:
http://www.cruisersforum.com/forums/f134/world-magnetic-model-plugin-58167.html#post658775

In the example hereunder (from GUI no. 2 above) the nautical translation of "Declinacion magnética y Variación anual" is: "Magnetic variation and annual change".