基于ArcGIS的渭河下游洪水淹没面积的计算

计算洪水淹没面积一直是灾害评估研究中的一个热点问题以GIS技术为基础,运用Arc-GIS软件的特殊功能,以渭河为研究背景实现了无需编程即可完成对洪水淹没面积的提取及计算。在地形图数字化基础上,分别对有源淹没和无源淹没进行分析,并运用ArcMap和ArcView软件自身的功能,对洪水淹没面积进行统计计算,并以2003年渭河下游洪水淹没数据为依据进行对比验证,取得了良好的效果。

ArcGIS applied in flood submerged area calculation at lower reaches of Weihe River

The calculation of flood subgerged area is always a hot topic and core areas in the disaster assessment study.In the floods submerged analysis,there are two different cases,the so-called "non-source flood"and"source flood",for determining flood area based on DEM and under the given water level condition.Non-source flood corresponds to the case with well-distributed and large area rainfall where all the low-lying land may have a flood disaster,and in this case all the points with elevations below the given water level should be included in the flood area.The"source-flood" is the case of flood flushing through the surrounding lands that needs to consider"circulating" condition.Because flood may be obstructed by ring structures or high lands,thus it can only cover the place where it flows and reaches.One of the computer processing method is the seed-algorithm.Based on GIS technology and at the background of Weihe,using ArcGIS special function,the paper pick-up or calculate flood submerged area without programming.Firstly the paper digitalizes relief map and analysis the "non-source flood" and "source flood",then using self function of ArcMap or ArcView to calculate flood submerged area of source flood and non-source flood area respectively;next,for proving means feasible,the paper takes 2003 flood data of lower reaches of Weihe River as example to contrast or validate.All of the results provide scientific basis for loss evaluation of flood calamity and have profundity significance to governmental preventing or controlling flood task.