Constructors of geometric primitives in domain ontologies for urban environments

A sustainable urban environment requires an integration of documentation and management systems in surveying and planning applications for different kinds of services involving services and processes. Traditional GIS approaches are geo-referenced to 2D information or, more recently, to a virtualized environment arising from the reprojection of textured views on 3D models. In this work, a tool for extracting dominant planes from dense 3D range information is applied for the automatic identification of structural elements (facades, ground and roofs) and their automatic labelling in terms of data of dominant planes. This tool is integrated inside the software platform UvaCad. The constructor of urban geometric primitives is given as a generator of 3D chains corresponding to the grouping of maximal planar quadrilaterals with ”similar properties” for the normal unit vector. As a by-product, one has a semi-automatic volumetric segmentation of small urban environments as support for the development of a Domain Ontology in urban environments. Our methodology is illustrated with some examples corresponding to small villages and typical central squares (Plaza Mayor) of old Spanish cities.