AUTOMATED CARTOGRAPHIC GENERALISATION OF BUILDINGS AND BUILT-UP AREAS IN O-O GIS
Yildiz Technical University, Department of Geodetic and Photogrammetric Engineering, Division of Cartography, Istanbul, Turkey
Cartographic generalisation is an essential process to derive geovisual products at multiple levels of detail. It is used intensively in medium scale topographic mapping. At these scales, true-scale representation is impossible due to scale reduction. Therefore, cartographic generalisation is inevitable in order to reduce and reorganise map objects for consistent and legible geospatial information communication at target scale. Feature classes are usually generalised separately due to their specific nature but regarding geospatial characteristics and relations of objects. Among them, generalisation of buildings and built-up areas has been a hot topic for researchers in cartography and GIScience. There are many approaches for this purpose; however, most of them are concerned with one or two generalisation operators such as simplification, displacement etc. In this paper, whole process of building and built-up area generalisation in medium scale topographic maps is handled. First general framework and strategy is given, mainly based on Voronoi diagrams, spatial analysis and processing, then some automated solutions are presented for individual and contextual generalisation operations for buildings and built-up areas in Gothic LAMPS2 object-oriented (O-O) GIS software beside available algorithms. A user interface is developed to perform a case study, together with database methods. Paper concludes with a general evaluation of results and addresses future work.