[GRASSLIST:3138] Re: blending seams in patch

Hamish hamish_nospam at yahoo.com
Sun Apr 11 21:25:04 EDT 2004

> I have four rasters that I would like to patch. Unfortunately there
> are 1 or 2 null cells along the common edges, which leave nulls in the
> resulting patched map. I would like to simply average "across" the
> nulls between adjoining rasters. I tried increasing the region
> resolution by 8x, but I still have unsightly nulls. Any suggestions?

try making a map with r.neighbors and then running r.patch with the
merge map listed as the first input and the r.neighbors map as the
second input (not sure if this is null safe? [does a 3x3 mean include
the center cell in the calculation?]).

If that doesn't work you might need to use an involved r.mapcalc
command with the average of a series of neighborhood modifier references.


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