On Sat, 7 Jul 2018, Micha Silver wrote:
If I understand, you have DEM tiles in one projection (location) and you're trying to use r.proj to transform the tiles into a different location. If that's the case, typically you would use the r.proj flag '-g' to get the region settings in the target location from the raster extent in it's source location. So you might do something like: g.region -p `r.proj -g loc=<source location> map=<source mapset> input=<source dem>`
Micha, I have no problems using r.proj to transform the DEMs from one location to another one. My question is why, when g.region is set to that of a county-wide vector map I cannot load a newly re-projected DEM that is the immediate neighbor of another DEM and both are within the county boundary and, assumably, in the same region. I don't understand how a raster map's region can change so drastically when reprojected from one location to another one.
Finally, once you have all the tiles reprojected, use g.list raster pattern=<....> sep=comma to get a list of all the tiles, then g.region -p rast=<list of tiles> to set the computational region to cover all tiles.
This assumes I can display the second tile. When I get that working I'll do this, but the county vector map's region should certainly encompass both.
One additional point: consider to patch all DEM tiles together in their native projection *first* then project the single patched DEM once to the target projection.
This would be a good idea, and I think I did this many years ago. But, when I read the r.patch manual page I see that it uses file B to fill in null cells in file A. What I want to do is join them by a common border, like laying tiles on a floor. If there's a r.patch option for this I've not recognized it, and I don't see another r.* module for assembling adjacent raster maps into a single one. Best regards, Rich _______________________________________________ grass-user mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/grass-user
