Apply View Mask

Use the Map Tools > Masking > Apply View Mask menu option (VIEWCLIP GX) to reset the clip area of a view to a polygon mask file.

Apply View Mask dialog options

Clip polygon file (.ply)	The name of the clip polygon file. Script Parameter: VIEWCLIP.FILE
Map view	The map view on which to apply the clip mask Script Parameter: VIEWCLIP.VIEW
Clip all groups	Force all the groups in the view to be clipped. Script Parameter: VIEWCLIP.FORCE

Application Notes

After changing a view clip area, groups within the view can be clipped to the view clip limits by setting their clip attributes. To do this, select the group to be clipped, press the right mouse button, and select the "clipped" option in the pop-up menu.

Polygon Mask Files

• Polygon files are ASCII text files with the default .ply extension.

• Each file contains a list of X,Y coordinates defining one or more polygons.

• Files can include any number of polygons, each with any number of vertices.

• The first and last points of each polygon are assumed to be connected.

File Structure Guidelines:

• Each polygon begins with a line starting with poly # (with p or P in column 1).

• Comment lines begin with / in column 1.

Creating Polygons Interactively

You can also create clip polygon files interactively using the digitising tools available in the Map Tools menu.

Example of a single polygon file:

Example of a three polygon file:

(Note the exclusive following the poly 3 entry; this indicates exclusive regions or holes in polygon sets.)