Design Of The Distributed Parallell PDF Map Tile Creation And Tile Service System

With the quick improvement of geographic mapping technology and the rapid development of Web GIS application,the scale of the geographic information data is growing exponentially.In order to realize the efficient access of these map data,map tile technology is widely used in current mainstream Internet map applications and GIS software.Therefore,how to realize efficient slicing of map data is still a problem to be studied in the current Web GIS solutions.The traditional single-machine centralized slicing data solution has problems such as not supporting Geo PDF map format,not supporting distributed slicing,low efficiency of tile construction and so on.Its processing speed is far from meeting the requirements of high concurrency and distributed efficiency of today’s Web GIS services.Inorder to solve these problems,this thesis designs and implements an efficient distributed parallel PDF map slicing and tile service system by using the core technologies such as PDF map slicing,multithreading and MPI.The main work of the thesis is as follows: First,combined with the existing slicing technology,this thesis designs a slicing algorithm for Geo PDF to enable PDF maps can be sliced as map data sources.Secondly,designs and implements a parallel PDF map slicing solution that supports single-thread or multi-thread,single-machine or distributed parallel configuration tile slicing,which satisfies the massive computing resource requirements for PDF map tile generation,effectively improves slicing efficiency,and provides a fast and efficient solution for the parallel construction of PDF map tiles;Finally,for the designed map slicing and tile service system,this thesis built a multi machine parallel environment based on MPI,analyze the factors that affect the efficiency of map slicing,and carry out performance tests on the designed map slicing and different slicing schemes of the tile service system based on the test example containing 100000 tiles.We evaluated the PDF map slicing function and tile generation efficiency of the system through a number of experiments and analyze the actual test results.Experimental results show that,the system designed in this thesis can effectively solve the problems existing in the current mainstream slicing applications,such as not supporting Geo PDF map format,slow slicing construction speed,low efficiency of tile pyramid generation and so on.It is a PDF map distributed parallel slicing solution with relatively low cost,scalability but significant efficiency improvement.