[GRASS-user] Downscaling DEMs (need some feedback)

[Jonathan Greenberg]

I'd like to resample a 30m DEM to 4m for use in the ATCOR3 topographic
correction software package.  The issue that always pops up when doing
downscaling like this is that the resultant "higher res" DEM contains the
"ghosts" of the 30m pixels (e.g. it creates squares in the landscape).  My
question is, what (if any) are the best ways to "get rid" of these effects?
Does GRASS (or other packages) have any tools to deal with this?  It seems
that the major issue is that a basic raster resampler treats the DEM as a
flat surface of equal elevation, but treating it as a grid of points, where
the center of each cell = the elevation, would be more appropriate (and
then, for each cell that is not the centroid of a DEM cell, the value is
some distance weighted function of the 4 elevation values which will
surround it).  Thoughts?

--j

--

Jonathan A. Greenberg, PhD
NASA Postdoctoral Researcher
NASA Ames Research Center
MS 242-4
Moffett Field, CA 94035-1000
Phone: 415-794-5043
AIM: jgrn3007
MSN: jgrn3007 at hotmail.com