摘要
利用流域范围内的格网DEM提取流域水文信息,并与当地枯水期TM影像进行对比,得出相应结论。研究采用国家标准比例尺1∶50000的数字地形图为数据源,利用等高线和高程点信息,在Arc GIS软件中生成研究区5 m分辨率的数字高程模型DEM,并在DEM的基础上,利用Arc GIS中的水文分析模块对研究区流域内的水文特征、水流方向、河网信息等进行提取,并将不同阈值条件下提取河网结果与TM影像进行对比得出以下结论:阈值设定为400000时吻合度最高,当阈值高于此值时,河网支流信息遗失较多,且部分主干道也存在断流现象;当阈值低于此值时,会出现很多在现实中不存在的"伪河道";利用DEM进行河网提取时会出现平行河网和主干道缺失的现象;在基于DEM提取河网的算法中,可以考虑在栅格上赋较高的水量值,代替上来水,但是这势必影响模型的自动化程度,同时赋值的大小也有待于研究。
The hydrological information of the basin was extracted by using the grid DEM in the watershed,and compared with the local dry season TM image to draw conclusion. By using the national standard scale1： 50000 digital topographic map as the data source and contour and altimetric point information in the research,5 m resolution DEM in the study area was generated in Arc GIS software,and on the basis of DEM,hydrological characteristics,flow direction and network information were extracted by using Arc GIS in hydrological analysis. After comparing the network extraction results in different threshold with TM images the conclusion is drawn that： the degree of anastomosis is the highest when threshold is set to 400000,when the threshold value is higher than 400000,it will lead to more river branches information loss,and part of the main stream has dried up. When the threshold is lower than 400000,there will be a lot of＂pseudo river＂which does not exist in the reality. The parallel river network and main stream will be missing when using the DEM drainage network extraction. In the algorithm based on DEM extraction river network,it is possible to replace the upstream water with higher water value on the grid,but this will inevitably affect the degree of automation of the model,and the size of the assignment needs to be studied.
出处
《水资源与水工程学报》
CSCD
2017年第5期117-123,共7页
Journal of Water Resources and Water Engineering
关键词
DEM
河网提取
TM
阈值
格网
TIN
流域水文信息提取
DEM
drainage network extraction
TM
Threshold
TIN
extraction of watershed hydro-logical information
