Comparing to creating shaded relief as semi-transparent overlay on the color raster map, this module gives result with more saturated colors.
The input for this module can be created for example using r.slope.aspect or r.relief.
NULL values are propagated by default, so if any of the two input rasters contains NULL cell NULL will be also in the output. If -c flag is used and cell in color raster is NULL, just shade color is used. If cell in shade raster is NULL, shading effect is not applied and original colors are used. If bgcolor option is used, NULL value in any input raster will be in the output replaced by the given color.
aspect
map in the North Carolina sample
dataset is used to hillshade the elevation
map:
g.region raster=aspect -p r.shade shade=aspect color=elevation output=elevation_aspect_shaded d.mon wx0 d.rast elevation_aspect_shaded
g.region raster=elevation r.relief input=elevation output=elevation_shaded_relief r.shade shade=elevation_shaded_relief color=elevation \ output=elevation_relief_shaded d.mon wx1 d.rast elevation_relief_shaded
haxby
color table.
Figure: A detail of raster created by applying shading effect of shaded relief (hillshade) to elevation raster map from North Carolina dataset elevation map