I want to calculate annual irradiance for a couple of buildings to establish how much PV energy can be potentially harvested.
Which algorithm You recommend for this purpose: "r.sun" from GRASS toolbox, or SAGA "Potential Incoming Solar Radiation" ?
Can You recommend any tutorial that explains step by step what inputs are required (i.e. not only DEM/DSM but also any atmospheric factors), what settings (or formulas) should be applied to obtain accurate results?
I am aware that this subject (or its elements) might be already discussed, but since I am a newbie, I am looking for comprehensive, holistic explanation what approach I should follow.