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

Abstract

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.