[GRASS-user] r.shaded.relief strangeness

[Patton, Eric]

>Not sure if this is very critical, but I have noticed a problem with 
>r.shaded.relief. If the region is set to 10m and then a shaded rel. map is 
>produced from a 30m input data, a corrupt map is produced. 
>
>example with spearfish data:
>
># set region, and force 10m resolution
>g.region rast=elevation.10m -p

I assume you meant g.region rast=elevation.10m res=10 -ap ?
 
># compute shaded rel. map from 30m res data:
># see image [1]
>r.shaded.relief map=elevation.dem shade=shade

I can't reproduce this. I can produce a Moire-patterned shaded-relief map, 
since I didn't resample the 30m data to 10m:

ftp://gsca.nrcan.gc.ca/outgoing/Patton

The command-line I used:

g.region rast=elevation.dem res=10 -ap
projection: 1 (UTM)
zone:       13
datum:      nad27
ellipsoid:  clark66
north:      4928000
south:      4914020
west:       590010
east:       609000
nsres:      10
ewres:      10
rows:       1398
cols:       1899
cells:      2654802

r.shaded.relief map=elevation.dem shadedmap=elevation.dem.shade.10m

Try r.resample first?

~ Eric.