Dem-based preprocessing method for depression filling in large river basins

Abstract

The invention relates to a drainage basin depression filling preprocessing method based on a grid DEM, and relates to a geographic information system and a grid-DEM-based drainage basin digital drainage system extraction method in a distributed hydrological model, in particular to a method capable of being applied to large river valleys. According to the drainage basin depression filling preprocessing method, a priority queue with the elevation as a keyword is used, picture elements are submerged gradually from the lowest picture element at the edge of the DEM inwards, the submerging sequences of the picture elements are recorded, and a submerging sequence matrix is obtained. All picture elements adjacent to the sea surface are added into a priority queue, the picture element with the smallest elevation is popped up from the priority queue each time, the height of the sea surface rises to the picture element elevation, and the submerging sequence of the picture element is recorded, then all picture elements, with the elevations smaller than the height of the sea surface, in the neighborhood picture elements of the picture element rise to the height of the sea surface and are added into the priority queue. An original DEM data set is replaced with the submerging sequence matrix so as to complete tasks such as flow direction extraction and riverway network extraction, and a complete drainage system network of the large river valleys can be extracted.

Description

technical field [0001] The invention relates to a method for extracting watershed digital water system based on a grid digital elevation model in a geographic information system and a distributed hydrological model, in particular, it can be applied to a depression filling pretreatment method in a large river basin. Background technique [0002] Extracting water system information based on digital elevation model (DEM) is an important method to realize numerical simulation of distributed hydrological model. The extraction of water system information in a watershed includes calculation of flow direction, cumulative flow direction, water system classification, and catchment network. At present, the eight-direction method (abbreviated as D8 method) is commonly used to obtain the above information, but whether the information can be successfully extracted depends on the preprocessing of the depression and flat pixels. At present, there are many software tools available for these...

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Problems solved by technology

Liu [Liu Yonghe,2009.Another Fast and Simple DEM Depression-Filling Algorithm Based on Priority Queue structure. Atmospheric and Oceanic Science Letters, 2(4):214-219.] proposed a depression filling method, which has a strong However, for large watersheds such as the Yellow River Basin, it is also impossible to obtain complete river system information after filling depressions

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