Research On Web-Based 3D Visualization Technologies Of Geographic Information Data

Since GIS had come to world,it had showed huge potential in variously fields.As the mature of the Internet,GIS is not just for the professional,but also entered common people's live.How to make it convenience and quickly,has become the hot topic.In real world.Geographic information is a kind of information which associated with time,space and dynamic.Although,Traditional display based on 2D can fulfil most visualization demands,it can not be perceived as simulate and directly,what's more,it would be limited in some specific situation.So far,the study of 3D WebGIS was just began.Not to mention when it based on Browser/Server structure(which is the main stream of internet),so many challenges had to be faced,such as the disunity about standards,poor efficiency for large-scale scene.So,this dissertation try to promote the visualization performance in 3D Web GIS based on high performance Geographic Information Platform.The main work can be concluded as following:1.Study and analyze the two different WebGIS structure modes,Web3 D technologies,then,constructing the whole project.2.We put our attention on the construction of terrain data in web circumstance.To view terrain data in web,we use Pyramid structure and level of detail strategy.Then,design every detail from organize,storage and real time manage.Furthermore,discuss a new Terrain Matching Algorithm.3.Do research on visualization of surface features in web circumstance.First,focus on model itself.After that,providing a new web loading strategy which according to the bounding sphere of model and the distance between the camera and model;continuous loading method for point cloud;At last,To solve the high cost of constructing virtual city,we using vector map to mass generate building;4.Designed and construct the 3D platform in the HIGIS project(863 program),expanding three extra function on it.