The potential annual solar irradiation
Calculation is performed in solar mapset. Mapset is set automatically before calculation. Before starting this module, it is necessary to calculate the potential monthly solar irradiation by the bbo.solar_month module. The module assumes that the summary monthly potential solar irradiation is saved in psr_d < xxx > files, where xx is two-digit number of month.The output raster layer is saved under the name psr_y to solar mapset.