| 摘要: |
| 历史时期沟谷侵蚀量的计算多采用传统实地测量或计算方法，而现代地理信息技术的发展为沟谷侵蚀量计算提供了更为简便、快捷、高效的方式。等高线图形概括法即为一种将传统制图学与现代地理信息技术相结合的方法。本文以神木县东山旧城冲沟为切入点，采用等高线图形概括方法，基于30 m 分辨率ASTER DEM，利用Arcgis10 平台计算历史时期沟谷侵蚀量，并将其与基于野外测量计算侵蚀量进行对比。结果对比发现，基于野外测量的沟谷侵蚀量约占基于DEM 侵蚀量的89.11%，两者之间存在一定差距，但是可被接受的。进一步分析显示，等高线简化前后，DEM 平均坡度、等高线长度和表面积均发生变化，平均坡度、等高线长度变化率分别为2.78% 和4.3%，表面积变化不是特别明显。三维分析显示，简化后等高线更加平滑，平均坡度趋于平缓，坡度的分布更为均匀。总体而言，等高线图形概括方法在沟谷侵蚀量计算方面具有较高的可靠性，对更大时空尺度内的沟谷侵蚀量计算具有借鉴意义。 |
| 关键词: 等高线图形概括 数据挖掘 沟谷侵蚀量 DEM |
| DOI：10.7515/JEE201401003 |
| CSTR：32259.14.JEE201401003 |
| 分类号:S157 |
基金项目:中央高校基本业务费项目(10SZYB10)；中国科学院重点部署项目(KZZD-EW-04-02)
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| 英文基金项目: |
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| The discussion of the computing method to historical gully erosion module in Loess Plateau |
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XIE Zhe-hui1,3, CUI Jian-xin2, CHANG Hong1
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1. Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China; 2. Center for Historical Environment and Socio-Economic Development in Northwest China of Shaanxi Normal University, Xi'an 710062, China; 3. University of Chinese Academy of Sciences, Beijing 100049, China
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| Abstract: |
| Usually, in terms of historical gully erosion study, historical geographers often prefer to field measurement or room observation based on terrain map in order to obtain the erosion module. So it seems outdated, especially with the rapid development of the modern geography information technology. However, simplified contour maps which combine traditional mapping with modern geography information system together may be regarded as a new solution to the gully erosion study. The main purpose of this study is aiming to calculate gully erosion volume more rapidly, conveniently and efficiently. The study area in this paper sites in the Shenmu County, 1.5 km away from the city, called Dongshan Castle which was abandoned in the Song dynasty in 1444 AD. Based on ASTER DEM with 30 m resolution combined with simplified contour maps and data mining method that are run on Arcgis10 platform, the gully erosion module is calculated and then is made contrast with the result obtained from field measurement. Consequently the results show as follows: (1) The gully erosion volume for DEM based and field measurement are 191431.26 m3 and 170591.85 m3. The later resulttakes about as 89.11% as the former. It demonstrates the reliability of the DEM based calculation. However, apparently there is indeed error existed and some subtle factors should be taken into consideration when the method is applied into estimating gully modules in small watershed. (2) Before and after simplification, average slope, contour length are 12.92°, 20670.11 m and 12.56°, 19772.33 m respectively. As for the average slope, it shrinks 0.36° about 2.78% of the value before simplified. The standard deviation of average slope reduces from 8.04 to 7.67 with the rate as much as 4.6%. The contour length decreases as much as 897.78 m, which takes 4.3% approximately. Given the gully shape, the rate of Surface area is not particularly significant. All of the changes suggest that after simplified, the contour turns smoother and average slope is leveling off and gradient distribution is more uniform. (3) Given the rationality and feasibility of the simplified contour map method, it may provide a new solution to calculate gully erosion module and is probable to supply reliable data for the historical gully erosion study. |
| Key words: contour simplified method data mining gully erosion module DEM |
