基于F-DEM的洪水淹没区精确快速提取

洪水淹没区包括洪水淹没的范围与深度,准确、高效地获取洪水淹没区是洪灾评估及减灾救灾的关键。本文针对现有洪水淹没范围与深度的快速计算及精度方面的不足,设计了洪水淹没区精确快速提取方法。首先,通过特征嵌入式DEM(F-DEM)数字地形建模技术,修正常规格网DEM对沟渠、坎堤等突变地形描述的失真问题;然后,基于洪水水位监测数据,采用Kriging内插模型构建洪水淹没面;最后,通过GIS多层面叠加及空间查询分析,获取真实淹没区信息。以温州水头镇水位监测点数据为基础,对其暴风潮后的洪水淹没区进行了分析,并利用大区域模拟水位监测点数据对提取方法效率作了测试。实验结果表明,该方法能较好地解决大区域海量数据条件下的淹没区提取问题。

Fast and Accurate Data Extraction of Flood Submerged Area Based on F-DEM

The basic attribute of flood submergence contains the inundated area and depth which are the core factors in flood disaster. The accurate and efficient obtaining of inundated area is critical for flood assessment and disaster relief. In recent years, forecasting and simulating the flood inundated area has been a hot topic in applied hydrology of GIS by using digital elevation model (DEM) data. However, it is always more difficult to get the inundated area and depth of flood submergence and normally needs more computing time to calculate the inundated area and depth since large study area and huge data. According to the disadvantage of existing method in computation speed and accuracy, a fast and accurate method for flood submerged area extraction is provided in this paper. Firstly, the distortion terrain when describing the discontinuous terrain such as ditch and dike by regular grid DEM is revised by taking the advantage of terrain features preserved grid digital elevation model (F-DEM). After corrected, flood submerged surface is created according to the Kriging interpolation model based on monitored points of flood. At last, combined with the basic principle of flood submerged extraction, the true area of flood submergence is obtained by using analysis techniques of overlay and topology spatial location in GIS. Based on the data of monitoring points in Shuitou Town, Wenzhou City, the flood inundated area is analyzed. And, the efficiency of the extraction method is tested by the monitoring points of simulation level in a large area. The experiment results show that:(1) The extraction method works well in the discontinuous terrain such as ditch, farmland and dike and the connectivity of submergence could be maintained effectively. (2) Calculating the connectivity of submerging is the most time-consuming part of the submerged area extraction. Compared with seed filling algorithm, the computational efficiency of the method in this paper rises by 90%. All in all, this extraction method has the ideal precision and efficiency which can better solve the inundated area extraction issue and provides scientific assessment for flood estimation and disaster relief.