The Use of GIS as a Decision Support Tool for Evaluating Fragmentation by Roads

The pollution of the environment by increasing traffic is caused by air pollution, noise pollution and fragmentation. While air pollution is decreasing because of technical improvements and pollution of noise is at least not increasing, fragmentation by roads emerges as the central problem. This issue is elucidated by trying to incorporate decision support tools into GIS.

Regional planning processes are aiming for ecologically responsible mobility. Planning is a decision support process in which almost every step within a planning process contains an evaluative part, so that there has to be a comprehensible scale for evaluating these data.

A multi-level approach for performing an impact analysis  is proposed.  At the top of this hierarchical approach (type level) an evaluation scheme has to be established for evaluating the more detailed levels (object level I and II).  Criteria at the type level are more general and try to satisfy general ecological guidelines whereas criteria at the object level try to grasp the specific impacts of the roads.

It is suggested to distinguish between differently urbanized regions within the evaluation. ATKIS, the federal topographic-cartographic information system of Germany, is used to establish an evaluation scheme for the impact of road construction which takes the different priorities into account.  The study area, the Region of Stuttgart in Southern Germany, can be subdivided into categories of different types of urbanization, which can be automatically derived. The methods for deriving the urbanization types are introduced. It is shown at the example of two different guidelines how the evaluation of roads can differ depending on the urbanization category.

This research is done at the regional scale (1:25,000 to 1:50,000) which appears to be optimum for management and planning tasks. The scale is not so detailed that the view for the whole is getting lost and on the other hand it is not so broad that the negative effects of roads cannot be presented in a spatially differentiated way anymore.