Two source DEMs each cover half the project analytical area. I want to
join the two into a single raster DEM. Tried using 'r.mapcalc dem_proj =
dem2 + dem3' but that did not produce anything visible. From reading
mapcalc.pdf and mapcalc-algebra.pdf I know the module is designed for
combining multiple raster maps cell-by-cell. I've not found how to
edge-match and join two rasters that do not have overlapping coverage.
Please pass me a pointer to the appropriate module to use for this
operation.
Two source DEMs each cover half the project analytical area. I want to
join the two into a single raster DEM. Tried using ‘r.mapcalc dem_proj =
dem2 + dem3’ but that did not produce anything visible. From reading
I think that the '+'operator honors NULL cells, so anywhere that is NULL in either raster will be null in the result. That’s not what you want in this case.
mapcalc.pdf and mapcalc-algebra.pdf I know the module is designed for
combining multiple raster maps cell-by-cell. I’ve not found how to
edge-match and join two rasters that do not have overlapping coverage.
Please pass me a pointer to the appropriate module to use for this
operation.
r.patch does this.
As per the man page, be sure to set the region to all input rasters in advance:
g.region rast=dem2,dem3
···
--
Micha Silver
GIS Consultant, Arava Development Co.
[http://www.surfaces.co.il](http://www.surfaces.co.il)