Preparation of local data

The method involves determining the sets of coordinates of real locations based on the data of the data sources (230-233). An area is defined based on set of coordinates for real locations of the data sources. A value assigned to the area is determined. The overlapping areas defined for data source is aggregated so as to obtain non-overlapping areas with assigned value for data sources. The non-overlapping areas are superposed with the assigned values to obtain a value distribution which reflects an overall situation with regard to the aspects in a real region. Independent claims are included for the following: (1) a device for upgrading location-related data; (2) a system comprising device; and (3) a program for upgrading location-related data.