A Collaborative Method For Displacement To Solve Map Road Feature Graphic Conflict

In the new era,people's cognition of map is getting deeper and deeper,and new technologies related to map emerge in endlessly.This trend makes the automation of map generalization develop in the direction of urgent research.As an important feature of map expression,roads need to conform to people's cognition laws.In order to express clearly,road features need to be symbolized.As the scale is reduced,road graphics conflicts will occur.In the traditional generalization method,the displacement is the main method to solve the road graph conflict.The road graph generalization,the displacement and the graph conflict detection are all independent processing processes,in which the road graph conflict often needs to be detected many times.In order to improve the efficiency of the graph conflict processing,the displacement is the main method and the other methods are used at the same time It is a reasonable choice to improve the efficiency of graph conflict resolution by cooperating with other generalization operators.The research object of this paper is the graphic conflicts of map road features.In order to effectively solve the problem of road feature graphic conflict in the process of generalization,maintain the spatial relationship between road features and the shape characteristics of road features,this study proposes a method of map road feature collaborative displacement based on Snake displacement model.This method can choose a suitable way of graph generalization according to the types of graph conflicts,and improve the automation level of graph conflict resolution in the computer environment.The road data of Open Street Map website is selected to verify the feasibility of the method.Based on the research of domestic and foreign scholars,this paper takes map road feature as the research data object type,and its main research results and innovations are as follows:1)The detection method of map road featuregraphic conflict is studied.CDT(Constrained Delaunay Triangulation)is used to detect different types of graphic conflicts in map road features,and to calculate and store road bending feature information considering road bending feature.By constructing CDT,the skeleton lines of the curved part of the road are extracted to identify different types of graphic conflicts.CDT triangles are classified.Different types of skeleton lines are composed of different triangle paths,and different types of skeleton lines represent different road graphic conflict sections.2)This paper studies the method of collaborative displacement to solve the conflict of map road feature graphics.Multioperators and Snake model are used to solve the conflict of road graph.The parameter setting of Snake model is discussed.Snake model is used to calculate the range of displacement propagation.The graph conflicts of road features are divided into two parts: the inner graph conflicts of road and the graph conflicts of road network.The inner graph conflicts of road are dealt with by using collinear,delete,stretch operators and Snake displacement model,and the graph conflicts of road network are dealt with by using collinear and Snake model.3)The road data downloaded from OpenStreetMap website is taken as the research object to realize the experiment of the above method.Three kinds of road data,which are road data of typical road section,road data of internal graph conflict and road data of graph conflict of road network,are respectively selected for experiments.Different types of graph conflict are detected by constructing CDT.On this basis,different processing is carried out for different conflicts to verify the effectiveness of the proposed method.