Monitoring Suburban Dynamics in the Greater Vienna Region

Large cities and their surrounding areas are faced with the trend of increasing suburbanisation. City and regional planners are called upon to provide concepts for these developments and thus need data on which to base their models. Until now, detailed information has in general only been available for large cities, rarely going beyond the city limits. Basic information, such as census data, is of course available, but usually only on a census tract basis, with no additional more detailed spatial reference. In this paper the use of satellite imagery is proposed to provide information on built-up areas in suburban regions. On this information any type of statistical data can be projected, allowing a better visualisation of the data and a better interpretation on what the statistical data actually means in a spatial context. Satellite images offer the advantages of covering large areas and being available on a regular basis. In order to derive detailed information on built-up areas from high resolution panchromatic satellite images, a texture analysis is proposed. This approach allows an automatic differentiation between settlement/no-settlement. Using visual interpretation, the settlement mask can be further subdivided into different urban classes (e.g. residential, industry, etc.). As an application the texture analysis was applied to panchromatic satellite images from 1968 (Corona) and 1999 (IRS-1C) for the City of Vienna and its surrounding areas (covering approximately 7.000 km²). This resulted in a detailed mask showing the extent of all built-up areas in that region. Based on these data numerous questions can be addressed. They range from simply showing where building activities have taken place to more complex questions by integrating the settlement mask with socio-economic data in a GIS. As a sample application census data was combined with the settlement mask for the analysis population pressure to examine the dynamics of settlement developments.