gdallado edges

[Frank Warmerdam]

On 7/28/05, Travis Kirstine GIS Tech <tkirstine at jdbarnes.com> wrote:
> List,
> After running gdallado on several adjacent raster hillshade tiff images,
> seams or edges became visible whereas pre gdallado no edges were visible. I
> assume that these values are the no data values but is there anyway to
> remove the seams and why do they appear in the first place.

Travis,

Did you use -r average when building the overviews with gdaladdo?
I think that gdaladdo does not know about "nodata" values, and would
average nodata values into overview pixels which could give such an
effect.

You might want to rebuild overviews with the default "nearest" 
downsampling and see if they go away.  If that is the issue you
can open a bug in the GDAL bugzilla about the issue.  

Best regards,
-- 
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