DEM Considerations

When considering your analysis of a DEM, think about:

• The resolution of the DEM.  You cannot see features that are less that the size of the pixels in the DEM, and from the Nyquist sampling theory, you probably cannot see features smaller than twice the pixel size.
• The horizontal accuracy of the DEM.  If points are off even by a pixel in a grid, you might see displacements of features that are not real.  This will be most obvious is you create difference maps.
• Whether the DEM is a DTM or DSM.  For a DTM, the production process may not have removed trees and buildings perfectly.

Last revised  3/14/2014