The thematic layers are converted to raster maps and then assigned theme weight and class weight to find the product of these weights and then classify them according to the influence each layer have on the groundwater recharge (Dar et al., 2011). This is done for each decision making technique used, for instance;
According to Pothiraj & Rajagopalan, (2013), the equation used to calculate the groundwater potential map weightage using the Boolean logic technique is as follows;
geomorphology * 12 + drainage * 9 + lineament * 5 + geology * 8 + land use * 2 + relief * 4
Pinto et al., 2017, also demonstrates for us how the groundwater potential map is calculated using the AHP technique;
GPM = (MC1w * SC1r) + (MC2w * SC2r) + (MC3w * SC3r) + (MC4w * SC4r) + (MC5w * SC5r) + (MC6w * SC6r) + (MC7w * SC7r) + (MC8w * SC8r)
where GPM is groundwater potential map, MC1–MC8 is the main criteria (1–8 thematic layer map), w is weight of the thematic map, SC1–SC8 is the sub-criteria of each thematic layer map and r is the sub-criteria class rating of each thematic layer map.