地表空间水文过程三维可视化试验——以浙江黄土岭流域为例

地表空间水文过程涉及三维地理空间和一维时间,对其进行三维动态交互显示便于认知主体对水文过程形成正确的认识。本文以浙江黄土岭流域为试验区,结合地理信息系统和计算机图形学的方法和技术探究了流域空间水文过程的动态交互显示方法。利用OpenGL的三维建模和图像渲染功能表现三维的水文过程,其中双缓冲技术保障了水文过程时间变化的展示。探讨了表面建模,地形着色处理,光照法线计算,水体透明处理,时相水文数据处理及交互参数输入等方法,并建立了地表空间水文过程的显示系统。通过系统的运行表明,该系统能逼真地显示不同高程连续水体的三维动态变化。

3D visualization of spatial surface hydrological process:a case study at Huangtuling watershed in Zhejiang province

Spatial hydrological process involves the 3D geospatial and a temporal dimension.The visualization of it is helpful to understand it more correctly and more efficiently.In this paper an approach representing spatial hydrological process dynamically and interactively is developed,using Huangtuling watershed in Zhejiang province as a case area.Our research development involves the following major phases: 1) creation of ground spatial reference,2) 3D display of spatial hydrological process and 3) dynamic and interactive display.In the PC environment,OpenGL functions are called through Visual C to realize the dynamic 3D display.OpenGL functions are powerful in 3D modeling and rendering and therefore suitable for presentation of the spatial hydrological process,while the technology of double buffers ensures the continuous display of the temporal changes of spatial hydrological process.The main aspects of the approach such as surface modeling,terrain coloring,normal computation in lighting,water transparency handling,temporal hydrological data processing and interaction parameters inputting,are discussed in details. The system can display realistically the 3D dynamic changes of water continuum at different surface elevations,and the navigation and synchronized animation play important parts in observing,analyzing and comparing spatial hydrological process.