关键词: 地理信息系统, 洪水模型, 计算网格, 拓扑关系, 模型建模

Abstract:

The computational mesh should represent the geometry, physical properties and boundary conditions of the computational domain in the flood simulation model. Based on the cell shape the computational mesh can be classified into regular mesh and irregular mesh. The generation of regular mesh is easy and simple, and as for irregular computational mesh hydrologists usually generated it manually. Due to structure and shape similarity, the automatic TIN generation algorithm can be used to generate the computational mesh for flood simulation model. The detailed flood model construction process based on GIS is to (1) delineate the computational domain; (2) generate computational mesh; (3) generate the mesh topology; and (4) extract the model parameters. The model parameters include boundary conditions, initial conditions, hydrological and geomorphological parameters and as well as other parameters for controlling the model simulation process. GIS technology can provide some spatial analytical tools for extracting some of these parameters such as the manning coefficient(roughness parameter) and calculating the average ground datum of internal point of every mesh unit and the mesh nodes, improve the capacity for defining the spatial sub-units of the computational domain and provide a better method to discrete the computational domain with enough amount of computational mesh with suitable geometry. In the river reach from Huayuankou to Jiahetan in the Huanghe River these maps of topography, landuse, water conservation engineering, hydrological observation station were used to construct the flood simulation model, and the data structure of the computational mesh is described in detail.

Key words: GIS, flood routing model, computational mesh, topologic relationship, model construction