Shaded relief

Common shaded relief

Creation of shaded relief map has two steps. First, compute the shaded relief:
r.relief input=elevation output=elevation_shade
You can use the created raster right-away if you want gray shaded relief. If you want to combine it with color, you can also add both rasters to the Layer Manager and set opacity of the shaded relief. However, for the best result use d.shade module to combine both rasters. Use Add shaded map item in the toolbar (under Add other raster layers) or use the following:
d.shade shade=elevation_shade color=elevation
This has the advantage of not creating additional raster while enabling to use the shaded relief in diffident ways. Alternatively, it is possible to create the shaded raster map with color as a separate raster using r.shade module which does the same as d.shade but instead of rendering the image it creates a raster map.

We have used shaded relief raster for shading and elevation raster for the color, however any combination of rasters can be used to achieve different results.

Sky-view factor

Install r.skyview module from Addons using g.extension:
g.extension r.skyview
Now you can compute the sky-view factor:
r.skyview input=elevation output=elevation_skyview ndir=8
A higher number of directions makes the computation longer but it gives a finer result.

As suggested above, sky-view factor can be combined with other rasters using r.shade module.