Research On Key Technologies Of Surveying And Mapping Based On Dimension Constraints

Real Estate Surveying and Mapping is the basic work of our nation to implement real estate management.It is mainly used to investigate the status of houses and their land,and collect housing information,and fianlly generate real estate maps.It mainly includes the real estate survey,real estate map drawing,alteration measurement,and so on.Among them,the real estate alteration measurement refers to the existing real estate maps,conducts on-site measurement,and then returns to office datum management to redraw the house property map.The office work and field work are separated in this situation,which is inefficient and error-prone.In view of the above problems,based on the Android mobile platform,this paper studies the key technology of real estate field mapping under the dimension constraints,designs and realizes a real estate surveying and mapping software.It can realize the automatic modification and mapping of field surveying and mapping,and can also reduce the work of the real estate alteration measurement and improve the work efficiency.The main research contents and results of this paper are as follows.Research on parsing algorithm of DXF file.Taking DXF file as the source of house graphic data,this paper studies and designs the parsing algorithm flow of the file.The object-oriented idea is used to process the DXF file data,which realizes the organization of the house graphic data and the expression of the data structure.It also studies the preservation strategy of the file,realizes the preservation of the real estate map,and ensures the integrity of the file.Research on automatic reconstruction and real-time updating algorithm of house dimension chain.Combining the structural features of house graphics,this paper introduces the dimension chain and parametric drawing technology from the mechanical design field.Based on graph theory,and through the recognition of geometric constraint relationships,it proposes building a parametric model of the house using the data structure of undirected graphs and storing the geometrical entities of the houses and topological relations between geometric entities.This paper also establishes horizontal dimension linked list and vertical dimension linked list respectively to store dimensional constraints of geometric entities,and then topological sort is preformed to determine the order of solving process.The design dimension-driven and constraint-driven algorithms are also designed to solve house parameterized models in order to achieve the reconstruction of the house dimension chain and auto update of map based on dimension-driven and constraint-driven.The contour tracing algorithm based on vector graphics is also studied to realize the real-time solution and update of the house drawing area.The test results show that the algorithm achieves good results.Research on Server/client-based file transfer and display technology.A local FTP serverwas set up,and a DXF file transfer module based on FTP protocol was developed,which achieved the acquisition of map sources and the real-time upload of results.The real-time update display of the real estate map and the design of the user interaction function are completed based on the Android mobile terminal.The test results show that the user interaction function works well,the graphics update speed is fast,and the file transfer is stable.The design and development of Mobile platform real estate surveying and mapping software.Researched and designed DXF file parsing module,graphic display and parametric drawing module,database file storage module,interface interaction function module and FTP file transfer module and other software function modules.Through the verification,the experimental results are good and the system runs stably.