[gdal-dev] advice on feathering rasters together?

[Frank Warmerdam]

Matt Wilkie wrote:
> Hello,
> 
> Does anyone have any advice on how to feather rasters together so there 
> is not an abrubt transition from one to the other?
> 
> The circumstance: I have 16bit integer raster (a DEM) with some areas in 
> it I want to fix (lakes which should be flat). I've created a second 
> raster with the desired replacement values (fixed_lakes). However if I 
> blindly just substitute fixed_lakes.tif for dem.tif there are some 
> pretty abrubt transitions which are sometimes worse than the original 
> problem.
> 
> I've done this before using Gimp and 8bit images but gimp can't load 
> 16bit images without losing half the bits. (in layer pallet stack 
> fixed.tif over original.tif > transparency to selection for fixed layer 
>  > invert selection > expand X pixels > feather > flatten image; restore 
> spatial reference with gdalcopyproj.py)

Matt,

Sorry, I'm not aware of a way of a way of doing feathering along edges or
cutlines with gdalwarp and friends.  We did have this in the PCI image warper
and it might be nice to add to gdalwarp.  But currently gdalwarp doesn't even
support a vector based cutline.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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