High Resolution Airborne Scanner data for multitemporal sealing maps of Graz

Urbanization process is a major factor of change in Central Europe cities, where urban settlement structures have raised over the past decades, especially since the 2nd World War. Over the past 20 years the extent of built-up area in many western and eastern European countries has in-creased by some 20 % and far exceeds the rate of population growth in the EU over the same period (6 %). Several cities rapidly became regional centres or international nodes according to economic and political pressures. Urbanization causes land cover changes, which can lead to deeper social, economic and especially to environmental changes. Monitoring in soil sealing pro-vides basic indicators of the urban ecology because of its negative effect on the soil water bal-ance, microclimate, flora and fauna (destruction of habitats), noise and the urban heating.
The main objectives of this paper are to provide time-series information to define and locate the urban sprawl trends in sealing processes of the Graz/Austria and to document the application and integration of the sealing maps in planning purposes of building authority of the government of Graz (especially for constructing sewerage systems). Developments in soil sealing are largely de-termined by spatial planning strategies where unfortunately the effects of irreplaceable soil losses are often not sufficiently taken into account. The sealing of the soil causes significant (quantitative and qualitative) changes in groundwater recharging and in the water balance. These changes have to be recognized by the governmental authorities to construct appropriate drainage systems. Especially the heavy rainfall evidences in August 2005 with more than 120 mm/per day and ex-treme flooding and overload of drainage system strengthen the importance of detailed planning of urban watersheds and drainage system of the municipality Graz by means of remotely sensed generated sealing maps.
Multitemporal sealing maps which were generated by a digital classification of multispectral DAEDALUS Scanner data (1986, 1996 and 2004) are used for this study. The different methodol-ogy/approach of data analyses, their advantages and disadvantages for further applications in water management will be documented in this paper.