Research On Automatic Topology Construction Of 3D Spatial Entities Based On B/S Architecture

Topological relation as an important spatial relation has been a hot topic in the field of GIS.At present,the research on topology construction is mostly confined to two-dimensional space.In other words,the methods and technologies of two-dimensional topology construction are extremely mature.However,the nature world that we live in is originally a three-dimensional space,and the depth of topology research has been unable to satisfy people's needs.As a result,our topological research needs to go deeper into the three-dimensional space,which is also the original intention and purpose of this research.According to different purposes,the existing research divides the three-dimensional topological relations into inner topology and outer topology.Inner topology refers to the process in which topological elements such as points,lines and planes are used to search for objects and complete the construction of minimal spatial entities.External topology refers to the topological relations,among such elements as pointing,line,surface and body.This paper focuses on the algorithm realization of the internal topology construction through the topological elements with complete topological relations.On the basis of the existing research,according to the research status of three-dimensional topology,the conditions and methods of completing the internal topology construction in three-dimensional space are emphatically analyzed.The research mainly includes the following aspects:1.Models are created by VRML language.One is a complex spatial entity composed of simple three-dimensional graphics,and the other is a model of the school of surveying and mapping of Anhui University of Science&Technology.Among them,the data of the complex spatial entity model are obtained by referring to the same kind of model and equivalent reduction.The data of the building model of the school of surveying and mapping are based on the electronic map of Anhui University of Science&Technology and refer to the model data made by others before.2.Selecting appropriate spatial database to organize,storing and transmitting 3d spatial data.The Microsoft Access2010 relational database is used here.Using JavaScript language to complete the link with the VRML scene achieves the purposes of reading and display of data.3.Completing the automatic search of the smallest three-dimensional space entity through the algorithm,and completing the automatic construction of internal topology.The key of the algorithm lies in how to find adjacent faces and determine relative positions in the total polyhedron,which is the innovation point of the paper.4.After the construction of a simple model,the model combines with ASP technology to achieve a simple query of the topological relationship such as edge to edge adjacency relationship,node to edge association relationship,edge to polygon inclusion relationship between three-dimensional space entities,This paper provides appropriate algorithm steps for the construction of three-dimensional topology under the network environment and provides certain reference significance for the study of three-dimensional cadastral and real estate management problems and also enriches the study of topology,laying a good foundation for further space analysis in the future.Figure[29]Table[14]Reference[90]...