To install new charts and readjust existing for Sea Clear II, the Mapcal utility is used. We deliver it for free whenever you buy any of our AIS products.

A raster chart consists of an image and calibration data to translate image position to geographic position.

A minimum of 2 calibration points is needed. To verify the calibration a grid overlay can be used. A chart border containing the usable chart area can be created and is used for automatic selection of best chart. Both grid and border are drawn using the selected projection.

With PNG and BMP files, the calibration data must be saved in an external file, while WCI, BSB/KAPand GEO/NOS files have embedded calibration data. BSB/KAP and GEO/NOS files are precalibrated and can not be changed in MapCal.It is however possible to open and check the calibration. Previous version of SeaClear uses a different type of calibration, which can be imported to the new format.

OziExplorer .map files can be converted to WCI including calibration information and image data. Note that as .map files do not contain any original scale data, the scale is estimated from the meters per pixel. Only .map files pointing to a valid image file can be imported. WinGPS chart calibrations from .chi files can be imported. As images are in BMP format, directly readable by SeaClear, a calibration file is created in the same directory as the .chi file. After import, all images can be directly opened including calibration data. GMB files can be converted. If a matching IN8 file with calibration info is available it is included in the resulting WCI file. Scale must be entered manually, but when all images in a dir is converted it is only prompted for the first file, rest is calculated to match.

MapCal can also convert many types of images to WCI for use in SeaClear. BMP, PNG, TIF, JPG, PCX and many other file formats can be converted. Note that SeaClear does not support all these file formats, to use them the images must be converted in Mapcal to WCI format. If calibration data is available, it is embedded in the resulting WCI file.
<br>WCI files can be converted to BMP including calibration data, allowing editing or other image manipulation that can be converted back to WCI with calibration preserved.To allow autoloading of charts a database containing chart layout and scale for all charts is used.This database is created in MapCal, and must be updated if any calibration changes are done to existing charts or if new charts are added. Validity of chart datum is also checked.


Chart installation guide

The following steps are required to install a chart into SeaClear (to install BSB charts, see below).

1: Make a chart using scanning or screen dumps. SeaClear currently supports Fixed grid, Mercator, Transverse Mercator, Polyconic, Lambert Conformal Conic, Sinusoidal, Orthographic and Vertical Near-side Perspective projected charts.

Projections based on Transverse Mercator, such as UTM and Gauss, are also supported. Most projections works good for smaller areas, as is normally used for navigation. Most desktop scanner may be used. Color is nice. If scanning, do some test scans to get the best contrast, and be sure to have the chart aligned. Check that the longitude or latitude lines are parallel to the screen edges. The file should be in palette format (max 256 colors) and saved in uncompressed .BMP format or PNG. PNG generally generates much smaller files, but is a bit slower to load. BMP does not work with in night modes, so PNG is the recommended format to use if the image is not converted to WCI.

Several scans or screen dumps may be stitched together. A resolution of 100 – 250 DPI is recommended. A size of 2000 * 2000 pixels will use 4 Mb of memory when loaded, while disk space will vary with file format. With PNG, max 256 colors should be used, but as they are compressed, the number of colors does not make as much difference. Save the file in a directory in the SeaClear chart path.

2: Start MapCal_2.EXE. If WCI format is used, use Tools->Convert-> Single file to WCI to convert the image to WCI before calibration.

3: Locate your file, original or WCI, open with “File->Open Image”.

4: Use “Edit->Chart Information” to enter name, scale, projection and chart datum, the rest is optional (This dialog will Auto popup when opening un-calibrated images). If Lat Shift or Long Shift is used, the entered values will override the Chart Datum setting. Latitude 0 is zero for most charts, while Longitude 0, the central meridian of the Transverse Mercator, Polyconic, Lambert and Sinusoidal projection, is a predetermined longitude close to the chart. If not known, leave at 0 to have MapCal select an appropriate central meridian.If Lambert projection is selected south and north standard parallels will be prompted for, set to 0 if unknown to have Mapcal select default. For Orthographic and Vertical Near-side Perspective parameters must be correctly entered,
estimations normally result in wrong parameters. Priority is used for auto-loading with 1 being the highest. A priority of 10 will be the same as half the scale, so a 25000 scale chart with priority 10 will be equal to a 50000 scale priority 1 chart. If you do not want charts to auto-load but show in list, use a high number.

5: Put at least 2 marks on the chart on known positions, far apart close to opposite corners, and enter the world coordinates. Except for Fixed and Mercator projections, a minimum of 3 points is normally needed. Position the cursor on correct position, right click to add a calibration point. Fine adjust if needed with the arrow buttons on the panel. Enter correct Lat/Long data.
6: Press “Activate Changes” (Step 2 and 3 can be done in either order). Now the grid will show in the density selected. To change grid color, click on the color square. If the grid matches perfect you are done. If grid does not match, select either mark from the “Calibration Points” list, move it with the N/S and E/W arrows as needed, or add additional marks. It will have world coordinates already filled in, so just move it with the arrows, or drag it with the mouse. Pressing “Activate
Changes” will show how it looks with the grid. This will do about the same as the old skewing, except you need to press “Activate Changes”. Calibration must be correct before step 7, as border is saved in world coordinates.

7: Click on the Border tab to make a chart border. Border-points are added the same way as calibration points with right mouse click. Or click “Set Border to Image” to get a border with a 5 point margin. This is done automatically during save if no border is entered manually.

8: Save your calibration with File->Save Calibration.
This should be all you need to do. After calibrating new charts, changing existing calibrations, adding
pre-calibrated charts like BSB/KAP, or changing the chart path, it is necessary to update or recreate
the Auto-load list for the new charts to load automatically in SeaClear.

Mapcal Reference

File Menu.
⇒ Open Image: Opens any image file, if cal data is available it is loaded.
⇒ Open From List: Find file by name, uses the Auto-load file.
⇒ Save Calibration: Saves calibration data (If it exists).

Edit menu:
⇒ Chart Information: Open the chart general info dialog. Enter scale, projection and chart datum, rest is optional. See step 4 above. Auto opens on new images.

Tools menu:Convert menu is for converting images format.
⇒ Convert ->Current to WCI: Converts loaded image to WCI format, including calibration.
⇒ Convert ->Current WCI to BMP: Converts loaded WCI image to BMP format, including calibration.
⇒ Convert->Single file to WCI: Most image types can be converted to WCI, including many formats that cannot be opened by MapCal or SeaClear. Images may be un-calibrated.
⇒ Convert->Images in Dir to WCI: Converts all image files in a directory. Images may be un-calibrated, as calibration may be changed on WCI files.
⇒ Convert->MAP in Dir to WCI: Convert all OziExplorer MAP and image files to calibrated WCI files.

Import Cal menu is for importing calibration data to a usable format.
⇒ Import Cal->Old SeaClear Calibration: Imports all found chart calibrations. Paths must be set and seachart.dir must be in the current directory. Any existing new calibrations are overwritten.
⇒ Import Cal->CHI Calibrations: Imports all calibration data from a WinGPS .chi file.

Autoload List menu is for updating the SCAINDEX.BIN file.
⇒ Autoload List->Scan for New Charts: Scans for new charts in chart path.
⇒ Autoload List->Update: Scans for changed calibrations and check for new in chart path. Any charts not found will be left as is (in case you have a CD path and the CD is not inserted).
⇒ Autoload List->Recreate Erases SCAINDEX.BIN and generates new, scanning all directories in the chart path. Only charts found will be in the list.Maintenance.

⇒ Remove Unused Calibrations: Removes any dormant calibrations remaining when images without embedded calibration data are removed from a directory.

Set Directories is used for setting all file path used by MapCal and SeaClear.
⇒ Set Directories: Set up all path needed. Updates the SEACLEAR_2.INI file.Will fold the panel to the left edge and maximize the work area.

To show the panel again, move the mouse over the left edge.

Installing pre-calibrated charts

SeaClear have built in support for reading normal BSB/KAP and GEO/NOS files, no conversion is needed. To display in the chart lists and to be used for automatic loading they must be registered.

Unregistered but calibrated images can be opened in SeaClear with “File->Chart->Not Listed.

sea clear

Installing BSB charts

The BSB/KAP file format is licensed from Maptech. BSB/KAP version 1 – 3 is supported. Projections based on Mercator, Transversal Mercator, Polyconic, Lambert Conformal Conic, Sinusoidal and Orthographic are currently supported.
Charts are available for most areas of the world from Maptech, NDI and many other sources. The actual chart is in a KAP file, while the BSB file only contains data regarding coverage and similar. As SeaClear keeps it’s own database, the BSB files are not needed.

Before using BSB/KAP charts in SeaClear they should be registered:

Start MapCal and make sure all KAP files are in the chart path.

From the top menu select “Tools-> Autoload list-> Scan for New Charts”. The KAP files will be scanned for name, coverage and other data and listed in the SeaClear autoload database.

Installing GEO/NOS charts

Projections based on Mercator, Transversal Mercator, Polyconic, Lambert Conformal, Sinusoidal and Orthographic are currently supported.The actual chart is in a NOS file, while the GEO file contains calibration data, coverage and similar.

Both the GEO and the NOS file are needed and must be in the same directory.

Before using GEO/NOS charts in SeaClear they should be registered:

Start MapCal and make sure all GEO and NOS files are in the chart path.

From the top menu select “Tools-> Autoload list-> Scan for New Charts”. The GEO files will be scanned for name, coverage and other data and listed in the SeaClear autoload database.

Installing WCI charts

Start MapCal and make sure all WCI files are correctly calibrated and in the chart path.

From the top menu select “Tools->Autoload list-> Scan for New Charts”. The WCI files will be scanned for name, coverage and other data and listed in SeaClear.

As WCI, KAP and NOS files are disk mapped, reading from CD will result in poor performance, therefore copying to hard disk is recommended.

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