Three-dimensional Buffer Analysis Algorithm Of Transportation And System Implementation

Buffer analysis is one of several important functions in space analysis, and is often used in GIS-T field. Now in GIS-T, the two-dimensional analysis algorithm has been ripe. But with the development of transportation into space and underground, traffic management and application need space analysis technology including 3D buffer analysis as the support. While the research is still in its infancy, traffic 3D buffer analysis did not have mature theory and algorithm. In the analysis of 3d data structure, paper proposes to use octree as the basic data structure to establish traffic 3D buffer analysis algorithm.This paper analyses the topotaxy between octree nodes and proposes a new octree neighbor finding analysis algorithm: 0-1 swap algorithm. The algorithm transforms linear octree octal code into 3D binary code, so just swap “0” and “1” in the binary code that we can get the neighbor nodes in corresponding direction. 3D traffic entity uses the new neighbor finding algorithm to extract the boundary nodes. And the transport entities buffer zone is formed by the relevant buffer structure which is generated by the different boundary direction. The experiment shows that 0-1 swap algorithm avoids traversing all octree nodes or using different calculation methods in multi target, and reduces the time complexity to O(n). Compared with traditional algorithm and classic Xiao’s algorithm, 0-1 swap algorithm greatly improves the efficiency of building octree topology relationship.During the algorithm implementation, in order to solve the problem that is slow to rendering and display 3D buffer, ray tracing is researched.0-1 swap algorithm is used to accelerated ray tracing, which can avoid traversing all nodes in the octree and improve the rendering display efficiency of traffic 3D buffer.Geographic 3D structure is researched. Geological structure simulation and section which is based on Kriging interpolation algorithm is realized by programing. Using grid structure, convergence model of road submerged is built and road submerged algorithm is generated, which can be used to calculate the catchment area and analysis the process of road submerged in the heavy rain day.Sudden traffic geological disaster emergency decision-making GIS system is developed by using 2D-GIS and 3D-GIS developer components. 3D geological structure simulation and section, heavy rains road submerged analysis and simulation, traffic 3D buffer analysis are realized, which can provide technical support for geological disasters of transportation emergency processing and aid decision making, etc.