Sealing calculations for West and East Berlin were made on the basis of different statistical data.
The West Berlin figures are based on satellite data from the (Landsat 5 satellite thematic mapper system (TM) gathered between August, 1985, and May, 1988. Factors affecting the choice of time of data determination were vegetal development, cloud cover and haze. Verification of satellite data was by supplemental data of areas of known ground sealing, and Color Infrared Photos (CIR) (at a scale of 1:4,000) taken in 1985. Aerial photographs were regularly taken in commission of the Berlin Department of Construction and Housing. This analysis was updated in 1991 on the basis on CIR aerial photographs from the 1990 flights, also in a scale of 1:4,000. Determination of area size was on the basis of municipal planning data of Department II (State Planning and Zoning) of the Berlin Department of Urban Development and Environmental Protection.
Sealing data for East Berlin are based on the interpretation of CIR aerial photographies in a scale of 1:6,000 from flights in 1990 and the evaluation of a map of Berlin in a scale of 1:5,000, in which building plot outlines are accurately portrayed.