The Generalization Method Research of River Network Based on Morph Structure and Catchments’ Character Knowledge

The generalization operation should first make decision of object importance at geographic level, which relates not only to the geometric properties of independent object but also the other context objects. In the channel selection of river network, besides the length and the distribution density, the order, the angle, the distribution pattern, proportion of left river branch and right river branch, distance between neighbor Channels and other parameters should be considered in the selection. How to get the information such as the order, the length, and the watershed area is the point of this article. In this study, these parameters can be extracted from Digital Elevation Model which can describe the terrain correctly. In this article, the channel selection during the river network generalization is four steps, first step is extracting different levels of catchments area and river network from 1:250000 Digital Elevation Model; second step is ordering the river; third step is deciding the river structure in small catchments; the forth step is selecting channel according to some parameters to get 1:1000000 river network data. The goal of first step is to decide the research unit of the river selection. The second step is to decide which channel should be deleted first and which channel is more important than others according to the watershed. The third step is the base of the forth step because the different river structure has different features. This article discussed the relationship between geographic feature of the river, watershed characters of channels and hydrographic generalization. The experiment of channel selection on this method shows it has good generalization effect. * Corresponding author of this paper: Qingwen Qi Tel: 86-10-64889078, [email protected] First author of this paper: Lili Jiang Tel: 86-10-64889078, [email protected]