- OpenCPN User Manual
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.
The hotKey "T" is an alternative for toggling the text.
In OpenGL mode, all text will always be horizontal when using the "Curse Up" option.
Second, double clicking on a vector chart, as long as the cursor has'nt changed to a green arrow near the edges, 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 lighthouse in a busy area.
Exactly what is shown in this dialog depend on the settings described below in "Display Categories".
Third, it is possible to select what font is used for the text on vector charts. There is an entry in theToolBox->Languages/Fonts->Choose Fonts tab, called ChartTexts. Here you select what font-face to use, and a template size. Weight and final size of the displayed texts depends on the charts you are using, but if the charts contain various weights and sizes, they will all scale together depending on what size you select.
The Options-Charts-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..
Other
Everything in "Standard" and more. This level could be described as "all essentials". More about what the IMO ECDIS says about the content of these three levels. This is a good choice for actual, underway, navigation, avoiding the possible risks involved in "Mariners Standard". See more below.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, but has been given a label that is easy to understand.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.
These Hot Keys all works in "Mariners standard". Features are toggled on/off with the keys.
| T | Texts. The visible texts are still affected by the settings in the Vector Charts settings tab. |
| L | Lights. Lighthouses as well as buoys etc are all affected. |
| S | Soundings. |
| A | Anchoring. This will affect information needed when anchoring. Anchorages and anchorage areas. Submarine cables and pipelines. Type of bottom. |
| O | Chart Outlines |
WARNING - it is possible to suppress essential information with "Mariners Standard".
If in doubt, switch to "Other", or use the "Select All" button.
Vector Palette
It's possible to change the whole look of a vectorchart. One example below....Detailed information is available in Vector Palette
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 "Light" in the Mariners Standard list of available filters, and untick it.
Press the "Apply" button!
Much better!
In this particular case, there is a shortcut. Use the Hot Key "L" to toggle all lights on/off.
Depth Soundings
turns the measured depths on and of. Other settings also affects when soundings are displayed, for example "Reduced Detail at Small Scale". 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 the 20 m contour stands out in black.
Chart Information Objects
earlier called "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, the quality of the survey, the latest NTM update and sources for the chart.
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.Reduced Detail at Small Scale
makes sure that a minimum scale is required before certain objects are shown. If this box is not ticked, everything is always shown, leading to very cluttered view at small scale (zoomed out).Bouy/Light Labels
displays names and purposes of aids to navigation, such as number or name of buoys, information about conspicuous objects etc
Light Descriptions
this tick box control display of light characteristics. Checking this displays a label with a text describing the marker or lighthouse's characteristics.
Extended Light Sectors
It is often difficult on a vector chart to see exactly what the light-sectors are supposed to do.
Activating the Extended Light sectors clarifies the situation. All sectors are extended and leading white sectors are emphasized in yellow and extend the full nominal range of the light-house. Just hold the cursor over a ligt and the extended sectors are activated.
De-Cluttered Text
Even when using "Reduced Detail at Small Scale", 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. For Lights with many sectors, the text label for each sector overwrite each-other. With this box ticked only the first sector label is displayed. For full information regarding sector lights, do an object query.
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 Detail Level (d)
The CM93 charts slider control that allows the user to adjust the screen complexity to suit the actual situation as well as the available processor capability.Normal settings depend on a combination of personal preferences and present usage of map. To see more details, the "CM93 Detail Level" slider, 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.
The slider can also be activated through the "d" hotkey, 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 scenario, prevent you from being aware of a shallow area.
There is no setting that fits all circumstances. For example a Sea-mount 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 Authorities, 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.
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