Mask DEM with Shapefile

From the Edit button on the Table display window of the database or shapefile.  Select the masking options (buffer size and whether to mask out or in).

The DEM has been masked with a USGS gazetteer database, filtered to show just the schools.

On the left, points outside a 500 m radius have been eliminated, while on the right those within a 500 m radius have been eliminated.

This could model the effects of a school drug free zone, for example..

This creates a bitmap with the database plotted, and compares the color with the desired masking inside or outside the areas).  For best results, in terms of both speed and accuracy, use a 1:1 map view.  

Because this shape file is a gazetteer, you could also Mask DEM with gazetteer which allows for some easier filtering.

Last revision 7/24/2008