The information on the degree of sealing has been obtained from aerial photography, satellite images and topographical maps (cf. 1993 Version).
For West Berlin, the pixels of the satellite image interpretation were transferred to the block structure and compared with aerial photography, and the degree of building ascertained from basic urban-planning data. For East Berlin, the non-built-up sealed area was estimated based on aerial photography. The degree of building (coverage with building structures) was also estimated.
Based on the 1993 Version, a main-focus update was undertaken for the approximately 20% of the block areas the use of which had changed fundamentally since 1990.
All tests undertaken in the interval to ascertain the development of the degree of sealing for all of Berlin, be it with higher-resolution data bases, e.g. satellite data of the imaging systems Landsat TM 7 and SPOT, or sealing data gathered terrestrially and lot-referenced by the Berlin Waterworks, has not yielded any satisfactory results. The values obtained differed strongly from each other, due to the different ascertainment methods.
The bases used to update the data stock for the 2004 Version (AGU 2002, 2003) included information from the geodata bases “Areas with Change Potentials of Overall Urban Significance,” of the Senate Department for Urban Development’s Urban Information, Urban Development Monitoring and Population Forecast Group, 2000; CIR aerial photography at various scales, 1999, 2000; digital ortho-images, 1:10,000, 1998; and the following digital maps: the Automated Properties Map (ALK) 1998, for the area within the Urban Rail Ring line (S-Bahn); the Digital Basic Map 1:5000 (Digk5), 1999, 2000; and the Map of Berlin, 1: 5000. Moreover, the utilization information on all existing basic planning projects of the State of Berlin (BEP) was evaluated.
With the aid of that data, a total of 5312 areas were updated as of 31 December 2001.