[GRASSLIST:7844] Re: visualize DEM error
dylan at iici.no-ip.org
Wed Aug 10 10:39:55 EDT 2005
Couple ways that are outlined in this book  suggest making
histograms of elevation and aspect data. if you see spikes at regular
intervals in either graph then you have some artifacts - possibly due
to the use of contours as your input data. You can do this with the
GRASS-R interface in a couple of minutes.
Another quick check, does your DEM support realistic flow patterns,
when modeled with something like r.terraflow? i.e. do numerous sinks
and dams cause water to move with no outlet, when expert knowledge of
the area suggests otherwise? Comparison with an alternate source of
stream data may also shed some light on the quality of the DEM.
How did you create the DEM, and from what type of source ?
 J. P. Wilson and J. C. Gallant, editors. Terrain Analysis. John
Wiley and Sons Inc., New York, 2000.
Soils and Biogeochemistry Graduate Group
University of California at Davis
On Aug 10, 2005, at 12:46 AM, orkun wrote:
> how can I visualize DEM error ?
> how can I interpret whether DEM which I have created is correct ?
> could you give me hints ?
> Ahmet Temiz
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