基于DEM的水流方向算法研究

水文信息在空间信息的表达中占有非常重要的地位，它被广泛应用于地形分析、资源环境管理以及水文科学等各个方面。流域是进行地表水文研究的基本对象，由于它反映了地域的水文、地质、地貌等特征，因此在水土保持、环境监测等方面具有重要意义，而基于格网DEM的水系自动提取是进行上述研究的基础。其中水流方向的决定是基于格网DEM的水系自动提取的重要环节之一。为了准确确定水流方向，该文在总结并实现现有的基于格网DEM的决定水流方向算法的基础上，综合FD8算法的多流向处理方法及Rh08算法对地形随机性的处理方法，提出了一种新的改进算法，并通过两组数据验证了该算法在水系提取时，对于多流向和随机性处理的优越性。

Research on the Algorithms of the FLow Direction Determination in Ditches Extraction Based on Grid DEM

Drainage information plays an important role in the presentation of spatial information and is widely used in terrain analysis, resource and environment management and Hydrology. Watershed, which indicates the characteristic of geology, geomorphology and hydrology, is a basic object in the research of earth surface hydrology. And it is very important in soil and water conservation and environmental monitoring. The automatic extraction of valley lines based on grid DEM is the base of the researches mentioned above. And the flow direction determination is one of the most important parts in the automatic ditch extraction. In this paper, we summarized and implemented the existing algorithms of flow direction determination in automatic ditch extraction, and proposed a new algorithm of flow direction determination, in which multiple flow directions and randomness were accounted for, based on the FD8 and Rho8 algorithm. We used two DEM data to validate the advantage of this algorithm in multiple flow direction and randomness.