Research On Aggregation Method Of Buildings(Footprint Polygons)on Large Scale Maps

The automatic cartographic generalization has been a hot topic in the field of GIS and cartography for many years.Seeking efficient and practical automation cartographic generalization algorithms is the key to completely solving this problem.Building aggregation is an operator in cartographic generalization so that research of it is of great significance.This paper has conducted a detailed study on the method of building polygon aggregation on large scale maps.The main research results and innovations are as follows:1)The polygon clustering method of buildings based on road mesh and MST is studied.Analyzed the method of clustering building polygons in the block based on MST comprehensively considering the spatial proximity,semantic similarity,shape and size similarity,direction similarity and other factors of buildings.The calculation methods of spatial proximity,semantic similarity,shape and size similarity and direction similarity among buildings for the aggregation of building polygons are elaborated in detail.2)Proposed a building polygon aggregation algorithm that can handle multiple topological relationship situations.Generally the design of the polygon aggregation method of two buildings is based on whether the two buildings are topologically adjacent or topologically separated.However,in real data,due to data fusion or digitization errors,there are topological intersects between building polygons.The algorithm proposed in this paper based on constrained delaunay triangulation can directly process this kind of data and make illogical topological relationships between buildings disappear after aggregation.3)The method of rectifying the spatial relationship between the building footprint polygons during the aggregation of the building footprint polygons is studied.When the polygon aggregation algorithm proposed in this paper deals with the building footprint polygon data of the building,the intermediate process data can be processed by the algorithm to obtain the corrected building footprint polygon that is consistent with the overall outline of the aggregated building.4)Designed and developed a software for building polygons aggregation.This paper describes the algorithm implementation logic of important modules detaily,such as triangulation,building clustering,and building polygon contour reconstruction in the program.The software implements the aggregation algorithm based on this.Experiments were carried out using the building data of the Wuhan,China area downloaded from OSM and the building footprint polygon data of Guangzhou.The experimental results reached expectations.After the aggregation,the right-angle feature of the building polygon was well maintained,The result of the building footprint polygon topology relation correction is consistent with the aggregated overall building outline,meeting the production requirements.Finally,compared with the results of polygon aggregation tool of the Arc GIS(version 10.2)map generalization toolbox.The comparison result illustrates the advantages of the algorithm proposed in this paper.