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| Subject: | [gislist] Processing elevation grid data |
| Date: |
01/20/2004 07:55:01 AM |
| From: |
Vassil Vassilev |
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Dear Listers,
Few day I asked a question about methods in ArcInfo for cleaning errors in
grid data representing digital elevation models.
Many thanks to Cynthia and Christian who suggested to use free softwares to
fill the 0 values and to merge the DEM I have with other DEM available.
The problem is a bit different.
The DEM I have do not have 0 values in itself, but sinks and peaks which are
sometimes with more then 100m. low or high than their neighbours. The pixel
size of the DEM is 23m - SRTM raw data. It is DTED format which I convert to
ArcInfo GRID using ERDAS Imagine.
I know how to fill 0 values - the problem is how to select them. Using FILL
command of ArcInfo does not gives the results I want because it fills only
very small ammount of errors - the majority of them stay.
Of course it is possible to use some filters but by this I am afraid that I
will generalize too much the relief features and the resultant scale will be
1:100,000 rather than 1:50,000 which I desire (and for which pixel size 23m
is O.K.).
Until now I tried also some techniques of ArcView Spatial Analyst - for
example to remove those pixels which 3D-area is much more then their 2D-area
- gives good result but again not for the whole dataset.
Again I am asking you if you have experience with processing elevation grid
data in ArcInfo to clean the elevation errors. I am sending you small jpg of
the generated contours from the original data to see the errors which I am
talking about.
Thank you again,
Vassil Vassilev
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