[gdal-dev] gdal_fillnodata smoothing water for a DEM

[Ivan Price]

Hi there,

I am currently investigating a way to 'smooth out' water bodies in a DEM, where the water bodies are initially marked as NODATA, and are then interpolated from the surrounding ground pixels. Currently the water varies in height as a result in slighy variations in the shore height, ideally I'd like to average that to a single value, specific for each water body.

I have tried using the python script gdal_fillnodata, this works fine but if I try to use the -si option the NODATA (water) regions are never filled.. as per the bug ticket:

http://trac.osgeo.org/gdal/ticket/3988

.. so the water remains textured / sloping.

short of this working I am proposing to define a mask / polygon for each water body in a scene and calculate the average, replacing the target pixels.

anyone have any suggestions why gdal_fillnodata is broken, or an efficient method of forcing water bodies to be the same height ?

cheers and kudos as always to the GDAL community

-i

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