[GRASS-user] wierd artifacts in DEM from seamless.usgs.gov
dylan.beaudette at gmail.com
Thu May 18 22:04:36 EDT 2006
downloaded a 1/3 arc-second (about 10m res) DEM from the seamless.usgs.gov
projected the lat/lon raster to UTM via gdalwarp using the -tps option
import into grass, and compute shaded relief... and it looks like crap:
so far the only way that i have been able to get a somewhat decent DEM from
this file is to :
a) average the heck out of it via r.neighbors size=15 or so
b) smooth it with r.param.scale size=15 or so
the artifacts appear to be at a regular interval ...
any thoughts one what could be causing this? I have never had this happen
before, although I have seen numerous scan-line style errors like this in
USGS DEM products. thoughts of artifact removal bring to mind the recently
mentioned Albani and Klinkeberg paper  and another by Oimoen  .
Any thoughts on how to proceed? perhaps a combination of band filters applied
in the direction and orthagonal to that of the artifacts?
I was hoping to use this area in the upcoming Where 2.0 talk, and it is
looking like I might have to choose an area with better elevation data if
this cannot be resolved. If it can be, then it would be a great slide to add!
Soils and Biogeochemistry Graduate Group
University of California at Davis
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