Research On Simplified Algorithm Of Vector Graphics Without Topologic Based On Fractal

In recent 30 years GIS(Geographic Information System) has obtained the extremely rapid growth. It is widely applied in resource investigation, environmental assessment, disaster prediction, land management, urban planning and transportation, etc. Researching anefficient simplified algorithm of vector graphics is of great significance, because GIS usually required the vector graphics to keep the main feature of the shapes in various resolutions.In order to solve the problem of vector graphics simplified without topological, this paper presents a new simplified algorithm of vector graphics without topological based on fractal inspired by Mandelbrot fractal measurement process. And in order to solve the problem of topology changes which usually occurred in the vector graphics simplifying, this paper presents a complete solution to keep the topological relationship between shapes.Following are the main works and contributions about this paper:(1) Presented a simplified algorithm of a single vector graphic based on partial variable measure in combination with fractal measurement theory. First, this paper presented a simplified algorithm prototype of a single vector graphic based on fractal measurement by simulating the fractal measurement process, Then analyzed the advantages and limitations of the prototypethrough some experiments. In order to solve the limitations, this paper further presented the improved shape simplified process using partial variable measure. The experimental shows that the algorithm simplified results keep the original shape features well, and the results have the basic fractalcharacteristics.(2) For two types of topology changes which might exist in multiple vector graphics, this paper presented some detailed solutions. About the algorithm keeping the contact of type, this paper presented a solution by splitting shapes, marking an order of vertexes, simplifying the partitioned shapes and merging. About the algorithm keeping the non-contact of type, this paper transformed a forecasting problem of topology changes to a decision problem of a relationship between the triangles and associated vertexes, and then presented a solution by using triangle regions to forecast, using partial variable measure to rebuild simplified vertexes. The experimental shows that the solutions are good about the two types of topology changes.(3) Packaged the algorithm logic as a dynamic link library, and developed a small GIS to test the entire performance of algorithm. In order to make the algorithm more easy to use, this paper use C# programming language of.Net platform to package the algorithm logic. In order to test the performance of the algorithm library, this paper developed a small GIS. The test results show that the algorithm library has whole functions, and the library implemented all logics about simplifying using partial variable measure and keeping topological relations.The all experimental show the simplified result is good using the algorithm of this paper. Whether a single vector graphic or multiple vector graphics, the simplified results are ideal. It can complete simplifying vector graphics quickly, at the same time keep the topological relations well between graphics.