Digital Terrain Analysis Based on DEM |
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Authors: | Huaxing Bi Xiaoyin Li Mengxia Guo Xin Liu Jun Li |
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Institution: | (1) Key Laboratory of Soil and Water Conservation and Desertification Combating, Ministry of Education, College of Soil and Water Conservation, Beijing Forestry University, Beijing, 100083, China |
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Abstract: | The digital elevation model (DEM), an important source of information, is usually used to express a topographic surface in
three dimensions and to imitate essential natural geography. DEM has been applied to physical geography, hydrology, ecology,
and biology. This study analyzed digital elevation data sources and their structure, the arithmetic of terrain attribute extraction
from DEM and its applications, and DEM’s error and uncertainty algorithm. The Hayachinesan mountain area (in northeastern
Japan) was chosen as research site, and the focus was on terrain analysis and the impacts of DEM resolution on topographic
attributes, analyzed using TNTmips GIS software (MicroImage, Inc., USA) and “Digital Map 25,000” (published by the Geographical
Survey Institute of Japan in 1998). The results show that: (1) DEM is a very effective tool for terrain analysis: many terrain
attributes (such as slope, aspect, slope type, watershed, and standard flow path) can be derived, and these attributes can
be displayed with both image and attribute databases, with the help of GIS; (2) DEM resolution has a great influence on terrain
attributes. The following details are shown: (a) DEM resolution has a significant effect on slope estimation: the average
slope becomes smaller and the standard deviation becomes larger when DEM resolution changes from fine to coarse, and the different
impacts of DEM resolution on different slope ranges can be classified into three gradient classes: 0–10° (underestimated slope),
10–35° (overestimated slope), and >35° (little impact on slope estimation); (b) DEM resolution has little effect on aspect
estimation, but flat areas become larger when DEM resolution changes from fine to coarse; and (c) the quantity of hydrologic
topography information declines as DEM resolution decreases.
Translated from Journal of Beijing Forestry University, 2005, 27(2) (in Chinese) |
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Keywords: | DEM digital terrain analysis DEM resolution GIS Hayachinesan |
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