基于GIS技术的淹没区确定方法及虚拟现实表达

给出了基于数字高程模型的 GRID结构 ,适合两种不同类型淹没区的计算方法 ,尤其是第 2种 “洪水淹没” 类型方法较有特色 .对于采用本方法计算淹没区 ,准确性受地形图等高距大小、数字化采集 精度、数字地面模型 (DEM )高程精度以及格网间隔大小、像素探测分辨率等因素的影响. 等高距越小 , 数字化跟踪误差越小 ,数字地面模型内插越密 ,格网跨度越短 ,探测分辨率越高 ,淹没区计算精度也就越 好 .空间数据总量及探测分辨率决定了整个算法模型的效率.最后 ,介绍了将淹没区范围采用 OpenGL 工具进行虚拟现实三维可视化所涉及的关键技术和方法.该方法在已完成的九五国家地方重大攻关项 目所开发的《大型网络级水利防汛及流域规划动态管理信息系统》中得到实现.

Study of GIS-based calculation of flood area and visualization of virtual reality

Two calculating methods of DEM-based Grid data structure for flood area have been proposed, and one of the calculating methods called "flood submersion" is quite characteristic. The accuracy of flood area is mostly dependent on the contour interval of map, accuracy of digitizing map, accuracy of DEM, and interval of GRID, detecting resolution of pixels. The smaller contour interval, the fewer errors of digitizing; The denser interpolating of DEM, The shorter span and the higher detecting resolution, the higher accuracy. The efficiency of the presented algorithm model is influenced by the detecting resolution and spatial data gross. Finally, the key technical method of virtual reality and visualization of flood area with OpenGL is discussed. Some practical applications for the given model implemented in the Water Conservancy Management Information System are provided in the last sections, which show that the model and algorithm are effective.