Zhaokou Irrigation District Main Canal Typical Section3D Visualization System

The traditional2D GIS is simple, fast, highly efficient, and has strong spatial analysis function, but on the other hand, it loses the elevation dimension information. There are a lot of limitations when the3D real world is projected onto the2D plane. Firstly, it doesn’t accord with our common cognitive habits for its simple abstract symbols; Secondly, lots of multidimensional spatial information, such as buildings and their environment texture information, rugged surface conditions etc., can’t be expressed and used directly; Thirdly, all of the spatial analysis related with elevation dimension, such as visibility analysis, measurement of volume,3D design etc., are hardly operated based on2D GIS. Therefore, the establishment of3D GIS is becoming an inevitable trend in the geographic information science development, and hence, the thorough application of3D GIS in this industry urgently awaits reinforcement.Firstly, the development of3D GIS technology at home and abroad, the current popular open platform and technologies are introduced. Secondly, because it is time-costing and labor-consuming to generate DEM by vectorizing map or digital surveying, this paper presents a solution based on shared resource to build the3D terrain scene:taking Aster GDEM as the terrain data resource, through clipping it by mask, generating TIN, then superimposing detail elements on TIN and editing it fine; at last superimposing GoogleEarth high resolution remote sensing image on the edited TIN to generate3D terrain environment, and experiments show that this way has a good visual result. Thirdly, this paper makes a study of the methods how to establish3D building models with shared technology:using SketchUp to creat3D modles of buildings quickly, rendering the models to generate realistic3D scene, then the.skp models are changed into Multipatch and stored in Geodatabase. Finally, taking Henan Zhaokou irrigation district main canal typical section as study area, using ArcEngine as a development platform, selecting Geodatabase to manage the spatial datas and attribute datas, a3D visual system is bulit in VS2008, and it realizes the3D scene browsing display, query and spatial analysis functions. 3D visualization technology is one of the core technologies to creat digital irrigation district, by using it can promote the efficiency of planning use of the irrigation district, it can also provide us with more information, so it has practical value to promote irrigation district sustainable development through using3D visual system.