Creating a Blanking File with the Digitize Command
One of the uses of the Digitize command is to create a Golden Software Blanking .BLN file. When creating a blanking file in this manner the header information is added to the file automatically. The file automatically assigns the NoData inside (1) flag to the polygon. If you wish to assign the NoData outside flag (0) to the polygon, click Options | NoData Inside Region in the Digitized Coordinates window to clear the NoData Inside Region option.
To create a blanking file with the Digitize command:
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Create a map in the plot window.
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Click once on the map layer to select it. This can be a map layer in an overlay, although the map cannot contain a 3D surface or 3D wireframe, or be tilted at any angle other than 90 degrees.
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Click the Map Tools | Layer Tools | Digitize command or right-click on the map and select Digitize. The cursor becomes a cross hair.
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Click the left mouse button in the plot window to write the current coordinates to the Digitized Coordinates window. Continue adding points in this manner. Digitized points appear as temporary small red plus-signs on the map.
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If you wish to create multiple polylines, click in the Digitized Coordinates window. Manually insert a blank line between the coordinates that make up each polyline. Each group of contiguous coordinates will form a separate polyline in the blanking file.
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If you wish to create a closed polygon, ensure the first and last coordinate are identical. You may need to copy the first line and paste it as the last line.
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When you are finished defining the polyline(s) or polygon(s), select theFile | Save Ascommand in theDigitized Coordinateswindow. Save the file using a .BLN extension.
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Press ESC on the keyboard or choose any toolbar button to exit digitize mode.
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Click the
button in the Digitized Coordinates window to close the window.