[GRASS5] Angle of incidence in viewshed/line of sight

[Graham Watt-Gremm]

Hello all,
Just so we don't re-invent the wheel, has anyone developed the code for
evaluating the angle of incidence from a single point in the landscape (i.e.
the point used for r.los) to cells within the viewshed? I am analyzing
repeated historical topographic survey photographs (more on this later) and
want to account for components of registration and classification error due
to terrain (angle of incidence). I have looked at the code for r.los and
r.sun and will be seeking help from some students in our new computer
science/geomatics programme as I am not (yet) a programmer. Look forward to
any suggestions...

Graham Watt-Gremm
School of Environmental Studies
University of Victoria