I have been trying to get a good looking shaded relief model out of GRASS and Qgis for a day or so now and just can't seem to get it. The biggest problem I'm having is the valleys look like mountains, but I just can't seem to get the right combination in order to show mountains and valleys look right.
Bellow is a some pictures of the problems:
DEM (Brown is high and Red is low, red is only used for a visual check)
Shaded Model 1 with DEM Sun position 180 degress from North, sun height 80
Problem: Hills look good but the river (in red) still looks like a mountain even though it's the lowest point on the map.
Shaded Model 2 with DEM Sun position north west (315 degrees), sun height 60
Problem: Again the hills look good but the river (in red) still looks like a mountain even though it's the lowest point on the map.
I have tried all different combinations of angles and sun heights and I just can't seem to get the river to look like a river, it always looks like a hill.
Can anyone point me in the right direction on what I might be doing wrong?
EDIT: So I took the contour data home and ran the process from the start and used the defaults for r.shaded.relief and got this:
This looks much better to me, not the greatest colours but we can change that. I think my work install of grass must be busted because even the defaults looked bad.
Best Answer
For relief shading in GRASS, better use r.shaded.relief. It comes by default with light from west to east. Like this (SRTM example):
For my perception the valley looks ok in this example. The colortable comes from r.colors (there are "terrain" and "srtm", see here for examples of these color tables).