Groundwater Three-dimensional Information Extraction And Visualization

Along with the exploitation and using of groundwater resource by human, its temporal and spatial variability has been severely affected by human activity. Land subsidence, groundwater pollution, and some other disasters follow the continuing withdrawal of groundwater. Meanwhile, the digital and information construction of groundwater resource becomes inevitable as the development of computer technology. This thesis studies on the extraction and expression of three-dimensional (3-D) information of groundwater, and the result could not only offer decision supports for groundwater resource management, but also prepare for the further groundwater digital and information construction.Firstly, this thesis builds the Digital Water Table Model (DWTM), which is similar to Digital Elevation Model (DEM). Here, kriging spatial interpolation technology is used to get regional water table spatial distribution according to scatter observing wells. Furthermore, an improvement was made to low estimation error when the scatter sample points are limited in quantity.Then, a quasi 3-D visualization of water table is realized by OpenGL on the basis of DWTM. Besides, contours and flow lines are mapped to make the spatial distribution and flow directions more clear, also dynamic variety of water tables is visualized by Timer method of Visual C++. According to the physical meaning of cone of depression, a numerical model is constructed referring to the characters of DWTM, and then seed algorithm is used to extract its location and boundary information, also visualization is included after the extraction. Conception model of groundwater divide, together with special structure elements and morphology operations are designed to extract its shape and visualize it. According to the relationship of land subsidence and water table, every node of DTWM, a raster grid, is regarded as a calculation cell for settlement information extraction.At last, this thesis applies the study onto three cities, which are Suzhou, Wuxi and Changzhou in east China, along Yangtze River. Some conclusions and suggestions are made on the consideration of reasonable groundwater exploitation and land subsidence control.The innovations of this paper are:ONE: More and deeper spatial groundwater informations are extracted and visualized by the combination of mathematical modeling and three-dimension visualization technology.