Ecological evaluation of urban biotope types using airborne hyperspectral HyMap data

Abstract

Urban biotype mapping is the most important database for ecological urban planning. The mapping contains complex information about the outfit and structure of biotopes in the form of descriptive parameters. However, quantitative parameters are limited to a manual estimation of the five levels of surface sealing. Therefore, municipal authorities are interested in quantitative parameters for an advanced GIS-based evaluation of urban biotopes. In this study airborne hyperspectral HyMap data are analyzed to identify urban surface materials based on their material specific reflectance features. The small urban structures and the high spectral information content of the hyperspectral image data require advanced methods for surface identification. Thus, a combined classification and unmixing approach was applied [S. Roessner et al., 2001]. The resulting dataset includes surface abundances of spectrally different materials and forms the basis for the derivation of quantitative parameters for each biotope, such as the weighted surface sealing and the portion of overbuilt area. Spatial and statistical analyses show that the results represent a contribution towards an improved quantitative evaluation of biotopes. In this way valuable remote sensing based parameters can be integrated into ecological urban planning processes.