In this early stage, analyst should define the study area and identify environment layers that should be considered in the analysis. Considering the previous experiences we suggest 400 m wide corridor around straight line between the origin and destination. But in these days digital information in suitable format is more and more available also in Slovenia. Several information layers have already been vectorised. Digital orthophoto can also be used as a background information.
Different experts prepare the data bases on fauna, flora soil, water, climate, etc.
When the data is entered, the estimation of area vulnerability is made, taking in consideration available information on the particular phenomena of the area. The vulnerability of individual environmental factor which is prepared on his own layer is shown in different colour shades. For example, grades from 1 to 4 are assigned to different soil types, according to perception of the expert. After then, all these layers are joined into one layer which is later used in the analysis. Total vulnerability of each polygon is calculated as a sum of grade multiplied by layer weight.