[GRASS-dev] question about merging DEMs at the edges

[Michael Barton]

In my project, we are patching together ASTER DEM¹s. The ones generated with
the new software from USGS are very nice. However, there remain artifacts at
the edges. Largely due to the fact that each DEM, in UTM projection, is
projected onto the earth¹s sphere in slightly different locales, when you
patch them together, the edge of one doesn¹t exactly match the elevations of
the adjacent one. In a few spot tests today, the difference is pretty small
<= 15m in elevation. But this is still enough to cause problems in
hydrologic modeling if your watershed happens to fall in 2 different DEM¹s
(as ours does). 

So does anyone have a suggestion as to how we can smooth out the artificial
scarp that occurs when we patch together a couple adjacent DEM¹s like this?

Michael
__________________________________________
Michael Barton, Professor of Anthropology
School of Human Evolution & Social Change
Center for Social Dynamics and Complexity
Arizona State University

phone: 480-965-6213
fax: 480-965-7671
www: http://www.public.asu.edu/~cmbarton 

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