The Map of Population Density is based on the file of mandatorily registered residents who have stated Berlin to be their main place of residence. This file was current as of 31 December 1994 and is managed by the Berlin State Statistical Agency (Statistisches Landesamt Berlin) (Berlin is both a city and a German state.). This file contains, among other things, the total of inhabitants registered with the Resident Registration Agencies for all statistical blocks in Berlin which have at least one inhabitant. The file is updated every six months on the basis of registrations, cancellations, and transfers.
The type and size of individual blocks and block segments was taken from the 1994 file of Area Types and Sizes in the Environmental Information System (UIS = Umweltinformationssystem) of the Berlin Department of Urban Development, Environmental Protection, and Technology. Criteria used for differentiating various areas were construction and open space structure type, age, and use (cf. Map 06.07, SenStadtUmTech 1996b).