地理学报 ›› 2003, Vol. 58 ›› Issue (6): 824-830.doi: 10.11821/xb200306004

• 生态系统与地表过程 • 上一篇    下一篇

DEM提取黄土高原地面坡度的不确定性

汤国安1,2, 赵牡丹1,3, 李天文1, 刘咏梅1,3, 谢元礼1   

  1. 1. 西北大学城市与资源学系,西安 710069;
    2. 西北大学大陆动力学教育部重点实验室,西安 710069;
    3. 中国科学院水利部西北水土保持研究所,陕西 杨凌 712000
  • 收稿日期:2003-07-19 修回日期:2003-09-03 出版日期:2003-11-25 发布日期:2003-11-25
  • 作者简介:汤国安 (1961-),男,浙江宁波人,教授,博导,中国地理学会会员。1999年获奥地利萨尔茨堡大学遥感与GIS专业博士学位,主要从事数字高程模型以及地形信息图谱研究。E-mail: tguoan@nwu.edu.cn
  • 基金资助:

    国家自然科学基金 (40271089);国家高技术研究发展计划课题 (2001AA130023);测绘遥感信息工程国家重点实验室高级访问学者基金

Modeling Slope Uncertainty Derived from DEMs in Loess Plateau

TANG Guoan1,2, ZHAO Mudan1,3, LI Tianwen1, LIU Yongmei1,3, XIE Yuanli1   

  1. 1. Department of Urban and Resource Science, Northwest University, Xi'an 710069, China;
    2. The Key Open Laboratory of Continental Dynamics, Ministry of Education, Northwest University, Xi'an 710069, China;
    3. Institute of Soil and Water Conservation, CAS and Ministry of Water Resources, Yangling 712100, China
  • Received:2003-07-19 Revised:2003-09-03 Online:2003-11-25 Published:2003-11-25
  • Supported by:

    National Nature Science Foundation of China, No.40271089; National High Technique Research Development Project, No.2001AA130023; Senior Visiting Scholar Project of National Laboratory for Information Engineering in Survey, Mapping and Remote Sensing

摘要:

选择陕北黄土高原6个典型地貌类型区为试验样区,采用野外实测及高精度的1:1万比例尺DEM为基准数据,研究栅格分辨率及地形粗糙度对DEM所提取地面平均坡度精度的影响。结果显示,对于1:1万比例尺DEM,5 m是保证该地区地形描述精度的理想分辨率尺度;多要素逐步回归模拟的方法进一步揭示了DEM所提取的地面平均坡度误差E与栅格分辨率X以及地形起伏的代表性因子—沟壑密度S之间存在的量化关系为E = (0.0015S2+0.031S-0.0325)X-0.0045S2-0.155S+0.1625,该结果也为确定适用的DEM分辨率提供了理论依据。

关键词: 黄土高原, DEM, 坡度, 分辨率, 不确定性

Abstract:

Slope is one of crucial terrain variables in spatial analysis and land use planning, especially in the Loess Plateau area of China where rugged terrains enhance serious soil erosion. DEM based on slope extracting method has been widely accepted and applied in practice. However slope accuracy derived from this method usually does not match with their popularity. A quantitative simulation to slope data uncertainty is important not only theoretically but also necessarily to applications. This paper focuses on how resolution and terrain complexity impact the accuracy of mean slope extracted from DEMs of different resolutions in the Loess Plateau. Six typical geomorphologic areas are selected as test areas, representing different terrain types from smooth to rough. Their DEMs are produced from digitizing contours of 1:10000 scale topographical maps. Field survey results show that 5 m should be the most suitable grid size for representing slope in loess area. Comparative and math-simulation methodology was employed for data processing and analysis. A linear correlativity between mean slope and DEM resolution was found at all test areas, but their regression coefficients were closely related with the terrain complexity of the test areas. If stream channel density was taken to represent terrain complexity, mean slope error could be regressed against DEM resolution (X) and stream channel density (S) at 8 resolution levels could be expressed as (0.0015S2 + 0.031S - 0.0325)X - 0.0045S2 - 0.155S + 0.1625, with a R2 value of over 0.98. Practical tests also show an effective result of this model in applications.

Key words: Loess Plateau, DEM, slope, resolution, uncertainty