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I've received a GeoTIFF DEM that was exported from Civil3D and at every contour there is a distinct terrace created when I process an aspect or slope in QGIS with the GRASS plugins.


I've looked around a bit and I think this is related to the algorithm used to create the DEM on the Civil3D side (Inverse Distance Weighting method). Are there parameters within Civil3D to prevent this? or Is there a way to process the terraces out after the file is created in QGIS?

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Such problems can be overcome with point sampling and reinterpolation. See for example here:

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Sorry, I hadn't logged in for a while, thanks for the input though. I ended up using r.neighbor and that seemed to work well. I'll study up on the reference above. Thanks! – Erin Apr 4 '13 at 23:07

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