Research On Indoor And Outdoor Navigation System Based On Web Virtual Earth

In the 21 st century,Smart City emerges in the context of the rapid development of computer science,big data,cloud computing and Internet technology.Smart city is a virtual platform to display various aspects of urban information.Visualization platform is concentrated reflection of the achievements and values of building smart cities.“Geographic information +” and urban management are driving forces of building smart sity.Web Virtual Earth,as the mainstream 3D GIS visualization platform at present,meets the visualization requirements of smart cities.GIS technology helps to build smart cities.And web conforms to the themes of knowledge and information sharing in the Web2.0 era.The visualization platform of 3D GIS can be used as the basis of smart city.It can deploy various services and applications based on the platform of 3D GIS,such as LBS services,digital city management,urban planning and design,live-view guides,threedimensional analysis services,etc.Web Virtual Earth has very high research value.Based on the existing research,the paper analyzed the current development satus,advantages and disadvantages about 3D GIS mainstream software in the market.Paper selected open source Web Virtual Earth framework-Cesium,loaded spatial model data,realized the basic 3D analysis visualization function of 3D GIS platform.Integrated panoramic visual scene and WebGL indoor scene on the Web,and realized indoor and outdoor navigation and browsing.Paper proposed to integrate the three different models into one Web system,and proposed to use different models for different levels and different dimensions,so as to make up for the shortcomings of each model.The dimension of visual scope extended from near-surface spatial data to indoor space.The outdoor citylevel scene is modeled by oblique photography and panoramic virtual technology The indoor scene is modeled by image-based panoramic virtual technology and WebGL twothree dimensional modeling technology.The paper realized a series of workflow from data acquisition,data preprocessing,scene model construction and model renovation,completed the construction of indoor and outdoor panoramic virtual model,indoor WebGL model and oblique photography 3D model.The paper used advanced front-end technology,based on Cesium,made profound study,integrated many services such as scenes roaming,3D analysis services,path navigation,and particle simulation.Paper designed and developed a 3D WebGIS navigation system that realized the integration of display and analysis,the integration of services,the integration of oblique photography 3D model,panoramic virtual model and WebGL model.The main contents of this paper are as follows:(1)Paper introduced the technical basis and theoretical foundations of oblique Photography 3D Modeling,panoramic virtual modeling and WebGL modeling.Author obtained the data needed for the three modeling methods of the research object,realized processed the construction of three models,modified the details of the model,analyzed the advantages and disadvantages of the three models,provided spatial model data for Web navigation system.(2)Author selected Cesium as the Web virtual earth visualization platform,introduced and studied the open source library Cesium,created basic image tile atlas data to enable offline map calls.And paper researched the algorithms involved in the Cesium visualization process,implemented basic data loading,3D analysis,particle simulation and other analysis functions in the Cesium module of the Web navigation system.(3)Paper used software-ArcGIS 10.3 to make the path vector map of indoor and outdoor scenes,used ArcGIS Server to publish map services for indoor and outdoor scenes,realized the path navigation and planning of the outdoor Cesium scene?the indoor WebGL scene on the same floor and across the floor.The path results obtained in the Cesium scene ware displayed dynamically.(4)Researched on switching ways of three model scenes in the Web,designed and implemented a Web system with complete functions,stable operation,interactive and beautiful interface.