The Urban Mask Layer as Reference Geometry for Spatial Planning: Moving from German to European Geodata

Abstract

In view of rising urbanisation around the world, it is vital to improve the analysis and evaluation of spatial settlement structures in order to ensure the sustainable design of associated transformation processes. Geodata and the maps derived from urban datasets can contribute significantly to understanding the characteristics of settlement structures. In this context, urban areas with a concentration of settlement elements form an important reference geometry. In Germany, such an urban mask is termed Ortslage and is included as an object type in the official topographical basic geodata (ATKIS). It would be useful to have a similar urban mask at European level, especially as a layer of the Urban Atlas within the framework of the Copernicus Land Monitoring Service. Here we present a GIS-supported algorithm to generate such a layer from Urban Atlas data. The method is demonstrated on 30 European cities showing a wide range of urban structures. Further, we compare the physical shape of the Ortslage with the urban mask, here illustrated by the city of Leipzig, Germany. As a basic example of the planning relevance of this method, we consider and discuss the metric shape complexity of the urban space for the cartographic comparison of cities. Furthermore, we address the question of a mixed automated-manual technology in the delineation of the urban mask. The regular updating of the Urban Atlas data within the framework of the Copernicus Land Monitoring Service opens up the possibility of integrating analyses based on the urban masks into the European Spatial Observation.