Automatic extraction of complex objects from land cover maps

The ESA Support to Topology (STO) project addressed the problem of extracting so-called complex objects, intended as particular land use elements (urban fabric, industrial units ...) from land cover maps, by means of topological relations among the different land cover objects. We developed an approach to give a semantic characterization to complex objects. Based on that, we developed a functional strategy to identify complex objects in an image and to build a visual representation compatible with the scale and resolution of the original map. The spatial operators, not only topological but directional and metric as well, were either taken from already existing systems or specifically implemented for the study. The developed approach and prototype web-GIS system, named Topology Software System (TSS), have been validated through several use cases, run by specialized end-users, in order to verify that the expected operations could be performed.