Three-Dimension Typical Spatial Analysis Method Of City Surface Scene

As progress of information technology, computer technology , geospatial information and its processing capacity have been greatly enriched and strengthened, the man is eager to take advantage of spatial information to understand and grasp the earth and the movement of social space, a virtual, scientific forecasts and regulation. Under the rapid economic development of rapid information and promotion of the good economic conditions of cities, three-dimensional digital urban systems have been set up. However, these systems focused primarily on three-dimensional visualization, as well as provide some conventional spatial analysis functions. As you known, with the provision of 3D GIS and 3D visual cognition, the number of cities also want provide some more profound analysis functions. Because of lack of new three-dimensional analysis and functional constraints, it becomes one of the main bottlenecks, with more extensive and in-depth professional application of 3D GIS in the field of digital city.This paper provides scientific lines and practical experimrnts as the basis of the analysis algorithm and the typical methods for urban construction and development, and hopes be helpful to decision suppor for man's "solution-oriented space-related issues" . The contents include:1.The theory and basic algorithm of spatial analysis . It is necessary to analyze firstly the content, methods and models on spatial analysis, and then the basis of spatial analysis algorithm, such as the spatial relationship, arbitrary polygon clipping (intersection,merge,difference, supplement), general delaunay triangulation, skeleton, and so on m, have investigated and proposed in this paper. Furthermore, it is also the basis of the number of complex spatial analysis proposed in the last parts of the paper. These lines have been applied in the triangular network construction and editing, rapid modeling for some typical features, extracting of roof and roof surface mesh based on the DSM data.2.Matching and integration of terrain model and object model. Because two kinds of models for the terrain model and features were modelled separately, the model of feature is often under or abobe the model of terrain under the cases of large-scale in the urban areas, such as the house on the mountain and the highway along with the mountain. In order to improve the visualization, as well as the accuracy of location, query and analysis, combine, to combine the model of terrain and features completely is necessarily. So the matching algorithms for terrain and features is investigated in this paper.3.Visibility and sunshine analysis. The analysis method in three-dimensional system is more complex than in two-dimensional, there exists many kinds of analysis methods. So, a typical wide visibility and sunshine analysis were focused on in this paper respectively. The aboved lines and algorithms were added the self-developed three dimensional software platforms. Via the experimental data, the correctness of lines and algorithms proposed in this paper are testified.