In 2010 − 2012 the hydrogeological model (HM) of Latvia called LAMO was developed by the scientists of Riga Technical University (RTU). LAMO generalizes geological and hydrogeological information accumulated by the Latvian Environment, Geology and Meteorology Centre (LVGMC). The commercial program Groundwater Vistas (GV) was used for running LAMO. In 2013 − 2014 LAMO was considerably upgraded. Density of the hydrogeological network (rivers and lakes) was increased, cuttings of river valleys into primary geological strata were accounted for, transmissivity distributions for aquifers were refined. To improve transmissivity data of HM aquifers, information provided by pumping tests for wells was used. The refined transmissivity data were applied to create the permeability maps of aquifers as the variable initial data for the GV system. To accomplish these task methods of numerical interpolation and digital image processing were used.