地球信息科学学报 ›› 2013, Vol. 15 ›› Issue (6): 871-878.doi: 10.3724/SP.J.1047.2013.00871

• 地理模型与算法 • 上一篇    下一篇

域间流域及自动提取方法研究

孙建伟, 汤国安   

  1. 南京师范大学虚拟地理环境教育部重点实验室, 南京 210023
  • 收稿日期:2013-11-18 修回日期:2013-12-10 出版日期:2013-12-25 发布日期:2013-12-25
  • 通讯作者: 汤国安(1961-),男,浙江宁波人,博士生导师,教授,研究方向为地理信息系统、DEM与数字地形分析及GIS空间分析。E-mail:tangguoan@njnu.edu.cn E-mail:tangguoan@njnu.edu.cn
  • 作者简介:孙建伟(1989-),男,硕士生,研究方向为数字地形分析。E-mail:sunjianweinjnu@gmail.com
  • 基金资助:

    国家自然科学基金项目(40930531、41171320);江苏省高校自然科学研究重大项目(13KJA170001)。

Inter-watershed and Its Automatic Extraction Based on DEMs

SUN Jianwei, TANG Guoan   

  1. Key Laboratory of Virtual Geographical Environment, Ministry of Education, Nanjing Normal University, Nanjing 210023, China
  • Received:2013-11-18 Revised:2013-12-10 Online:2013-12-25 Published:2013-12-25

摘要:

目前,基于DEM及常规GIS软件进行的流域自动分割方法,往往忽视了一般流域与域间流域的差异性,并且未在属性上区分二者。本文强调流域划分必须充分,明确域间流域的概念与基本特征(包括域间流域的数量与面积、空间分布及空间形态特征)。鉴此,本文提出了基于DEM的域间流域自动提取方法,并以陕北黄土高原丘陵沟壑地区为实证。结果显示:通过对汇流阈值、地形特征、数据边界效应等因素的影响分析,可实现对域间流域的快速准确提取。另外,本文还对此分析了域间流域与一般流域在水文、空间形态及空间分布方面的特征差异。

关键词: 流域划分, 域间流域, DEM

Abstract:

Watershed delineation based on DEMs in the GIS environment is a fundamental work for hydrological analysis. But the feature difference between normal and inter-watershed watershed has long been ignored. This text believes that existence of inter-watershed must be taken into account during watershed delineation and analysis. In this paper, an overall explanation of basic concepts and characteristics of inter-watershed is presented, and a method of extracting inter-watershed automatically based on DEMs is introduced. Experimental results in the Loess Plateau region show that inter-watershed could be extracted accurately and quickly after a comprehensive consideration of water accumulation threshold, terrain feature and the boundary of data. Generally speaking, flat topography may lead to the wrong position of outlets of watersheds, which can be corrected with help of rivers' DLG data. And if boundary of the data is not the dividing crest, it's difficult to determine whether a watershed whose dividing line consists of data's boundary is inter-watershed or not. Comparison of inter-watershed and normal watershed in terms of spatial form, spatial distribution and hydrological characteristics based on experimental results show that inter-watershed performs notable features. Firstly, spatial pattern of inter-watershed is clump and tends towards stability with growing minimum catchment area settled. Secondly, the amount of inter-watershed depend on the number of runoff node that means that it has a power function with minimum catchment area in the test area. And a good linear relation between average area of inter-watershed and average area of normal watershed could be found in the experiments. Thirdly, spatial shapes of inter-watershed make it collect water quickly if threshold value is settled larger than 0.4 km2 based on the statistic of shape index of the inter-watersheds extracted in the experiment area. In conclusion, the concept of inter-watershed is defined firstly and its basic characteristics are also interpreted. The method introduced contributes to ensure the correctness of watershed delineation. The study on inter-watershed is of great significance not only in fluvial geomorphology research but also the theories and methods of digital terrain analysis.

Key words: watershed delineation, DEM, inter-watershed