Delimiting the building heights in a city from the shadow on a panchromatic SPOT-image: Part 2: Test of a complete city

Abstract

The building heights and the heights' distribution of a city are important information for the research about the small climate of the city, the modelling of the signal transformation between the mobile phones in the city, etc. In this paper a test is shown, in which the building heights and the heights' distribution of a city (about 20 km by 20 km) are delimited from the shadows that are identified on a panchromatic SPOT-image. The identifying precision is 93 per cent by checking 200 identified buildings. The calculated heights of 77 buildings are examined and the root-mean-square error is 6-13 m. The high building density and overlapping of the grey value distribution between ‘shadow’ and ‘tree/bush’ on the image are two main inferences. The test shows that (1) the building heights and the heights' distribution of a city could be roughly delimited from the shadows on a very good panchromatic SPOT-image, and (2) the delimiting precision could meet the demands of the above two researches.