Thin DEMs

Thinning is a quick decimation.  It takes values from the original grid, and uses them in the final grid.  If you want averages, or minimums, or maximums, filter the DEM first, and then thin that grid.

The thin option is on the Raster GIS menu from a map with an associated DEM. To thin a DEM, you will:

• Pick the thinning factor
• If you want to save the DEM, use the File, Save DEM option, and pick the name for the new DEM.

A thinning factor of 2 will pick every other elevation in every other row, and will be ¼ the size of the original DEM.

A thinning factor of 3 will pick every third elevation in every third row, and will be 1/9th the size of the original DEM.

The thinned DEM will be smaller and will display faster. You might have to thin before you can merge DEMs if you have large DEMs or want to merge a very large number of DEMs, but in this case you might consider starting with a lower resolution DEM.

Alternative ways to downsample.

Last revision 11/27/2020