[GRASS-user] Basin DEM advice needed

Rich Shepard rshepard at appl-ecosys.com
Wed Oct 2 15:22:47 PDT 2019

Attached are two maps using 1m LiDAR data. The annotated map,
basin-elevations.png, was drawn by individually applying d.rast to each of
the 70 maps covering the basin. Sharp breaks can be seen where the data
cross quads or flights didn't match up smoothly.

The un-annotated map, nehalem-dem-patched.png, displays the results of
running r.patch on all 70 maps. Topographically it's quite different from
the individual maps; almost flat when the north, east, and south edges
should have elevations similar to the other map.

I think I should apply r.resamp.stats to aggregate the 1m resolution to 5m.
I'd like your thoughts on this.

I assume that I should resample each individual map, then re-run r.patch on
the coarser maps because r.slope.aspect and r.info need a single map as

Would this be an appropriate process? I'm completely open to all suggestions
and recommendations.


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