Research On Multi-scale Vector Map Rendering Technology

With the vigorous development of various sensor technologies,the means of obtaining data increases,geospatial data is developing in a high-precision direction,especially on vector map data.Facing the large-scale vector map,how to improve the rendering efficiency and the drawing effect by improving the vector drawing technology has become the bottleneck of the development of geospatial information technology.At the same time,the rapid development of Interne,to promote the desktop GIS applications to the Internet service of GIS progress.Vector mapping based on the cloud service architecture The online mapping model becomes more and more important and becomes mainstream.Therefore,how to realize the online and efficient rendering of space vector map in network service environment is a hot issue in GIS research.In order to solve the above problems,this paper deeply studies the method of reducing the efficiency of online mapping by reducing the large-scale vector data in the network environment.We mainly construct the detailed hierarchical model of the vector feature set,reduce the spatial redundancy of the vector map based on the cartographic synthesis technique.At the same time,based on the finite state machine model,a method between different vector drawing styles is proposed,which realizes the effective conversion of vector drawing patterns between different mapping platforms.In order to improve the efficiency of online services,the paper based on OGC network map service standards,research and implementation of a set of vector map parallel service tool.Specific research work is as follows:Firstly,under the premise of vector level hierarchical model based on surface vector detailing,we construct a point hierarchical redundant memory under different scale.According to the point,the line vector element is important in the degree of map information expression,Evaluation model,and put forward a method based on vector detail hierarchical model of visual effects lossless line element mapping method,and based on Delaunay triangulation point element synthesis method.Which effectively improves the redundant stacking of features caused by drawing large-scale vector elements in small-scale maps,and improves the speed of map drawing.Secondly,based on the finite state machine model,the method of vector pattern between different drawing styles is designed,the cross-platform transformation and mapping knowledge sharing of vector map drawing style are realized.Thirdly,based on the OGC service standard,a set of vector parallel rendering service tool based on web server is implemented,vector map slices,vector map drawing and publishing,and provides standard access interface to the Internet.