I wrote a script to do something like this at one point, though I can't find it now. It was intended for terrain, but could be used per band on imagery. It used r.buffer to create a distance gradient and then r.recode to convert this gradient to a percentage. I then used r.mapcalc to merge the 2 rasters based on the percentage.
The script automated the buffer distances and the creation of the recode.txt file, but went something like this: ## make a null raster r.mapcalc "temp_null = if(isnull(source),1,null)" ## create a distance gradient from the null raster. The output will have int values 1-7 where 1 equals the input null raster r.buffer in=temp_null out=temp_buf distances=10,20,30,40,50,60 units=meters ## fill nulls in the distance gradient with 0 for recoding r.mapcalc "temp_buf_fill=if(isnull(temp_buf),0,temp_buf)" ## recode to a percentage r.recode in=temp_buf_fill out=temp_recode rules=recode.txt where recode.txt would have the range from temp_buf_fill expressed as percentages: 1:1:100:100 2:2:86:86 3:3:71:71 4:4:57:57 5:5:43:43 6:6:29:29 7:7:14:14 0:0:0:0 ## merge the output r.mapcalc "merged=if(isnull(source),patch,(patch*(temp_recode/100.0))+(source*(1.0-(temp_recode/100.0))))" Sorry if that doesn't work, but hopefully you get the idea. - Jamie On Thu, Feb 24, 2011 at 10:53 AM, kaipi <mapcoll...@gmx.net> wrote: > > I need to patch rasters containing NULL areas with alternative rasters. I > can > do this with r.patch but due to different quality/resolution of the rasters > this produces prominent seamlines. Is there a way to feather/blend between > merged rasters using Grass GIS? > > Thanks, > > Kaipi > -- > View this message in context: > http://osgeo-org.1803224.n2.nabble.com/How-to-merge-rasters-using-feathering-blending-tp6061489p6061489.html > Sent from the Grass - Users mailing list archive at Nabble.com. > _______________________________________________ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user >
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