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论述了教字高程模型(DEM)与传统的地形图件的异同及优势,对构建DEM的技术要点,如技术路线、栅格数据处理、矢量数据处理的方法作了介绍,以北京八达岭森林公园总体规划为例,简述了DEM在地形分析、视域分析及树种选择与配置等方面的应用. 相似文献
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使用ARCGIS软件对五莲县地形等高线数据进行处理,以生成全县DEM,对DEM进行分析,得出全县地形坡度及坡向分布及面积数据,为林业生产及规划提供依据,同时展示了GIS技术作为一项具有强大生命力的高新技术在解决林业相关问题中的便利与快捷。 相似文献
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以福建省松溪县渭田镇吴村村为例,探讨运用ArcGis软件的空间分析功能,将矢量地形图转换成数字高程模型(DEM),再以DEM为基础获得林业区划小班的平均坡度并与林业小班数据库相关联的方法与步骤,同时分析了具体应用过程中矢量地形图的提取方法以及地形转栅格中DEM分辨率对坡度计算精度的影响。 相似文献
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基于影像区域合并分割技术的植被覆盖分级研究--以三峡库区小江流域为例 总被引:1,自引:0,他引:1
以影像区域合并分割技术为基础,综合运用相关GIS和RS软件,提出了植被覆盖分级研究的新方法.以三峡库区小江流域为例,以2002年的TM图像为信息源,结合研究区的地形图、GPS野外采样数据、植被指数和DEM等,对研究区的植被覆盖进行了分级研究.研究表明,三峡库区小江流域的植被覆盖总体上分布不均,但与流域区位及海拔高度呈现一定的规律性空间分布格局.这一研究对确定水土流失强度等级具有十分重要的意义,也为其它的遥感影像分析应用提供参考. 相似文献
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本文以帽儿山实验林场DEM数据为基础,利用ArcGIS10.0的水文分析功能,对帽儿山地区进行了水文分析,提取该地区水流长度、生成河网并对河网进行分级等。结果表明,用地理信息系统水文分析功能提取的河网与实际地形基本一致,可以作为一种工具,根据DEM数据来提取水文信息。 相似文献
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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) 相似文献
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We constructed sugi site index models using digital-terrain-analysis-based environmental factors for Miyazaki Prefecture.
We selected 18 sugi plantation stands which were pure, undisturbed, and over 40 years old, planted with the same sugi-cutting
cultivar, and managed by normal forest operations. The dominant tree in each stand was felled for stem analysis. Site index,
defined here as dominant tree height at 40 years old, was estimated by stem analysis for each stand. Five types of DEMs were
used: 100- and 50-m resolution derived from DEMs published by the Geographical Survey Institute, and 50-, 25-, and 12.5-m
resolution derived from digital contour map manually generated from a 1:25,000 topographic map. A total of 14 indices categorized
into solar radiation index, wetness index, and topographic exposure index were used to model the site index by multiple linear
regression analysis. Through model selection procedures, the best-fitted site index models were selected for each type of
DEM. The most precise model was that of the 12.5-m-resolution DEM (R
2 = 0.692), following the model of the published 50-m-resolution DEM (R
2 = 0.665). Site productivity of sugi was severely limited by direct solar radiation. Soil wetness also affected sugi site
productivity; however, it can only be represented using a high-resolution DEM derived from fine-scale data. Our results suggest
that the 50-m-resolution DEM published by the Geographical Survey Institute can be used for site index modeling. 相似文献
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基于数字高程模型(DEM),分别论述提取小班的海拔域值、平均海拔、坡度、坡向、坡位等地形因子的方法及算法设计,并举例计算,对所得结果进行误差分析后认为结果可靠、准确,能替代传统方法用于小班地形因子的提取. 相似文献
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Guopeng Ren A-Xing Zhu Wei Wang Wen Xiao Yong Huang Guoqiang Li Depin Li Jianguo Zhu 《Forest Ecology and Management》2009
Forest mapping over mountainous terrains is difficult because of high relief. Although digital elevation models (DEMs) are often useful to improve mapping accuracy, high quality DEMs are seldom available over large areas, especially in developing countries. In this study, a hierarchical approach coupled with topographic information derived from coarse DEM was developed to improve the efficiency and accuracy of forest mapping over mountainous areas. The overall idea of increasing mapping accuracy over large mountainous areas is to reduce spectral variety over areas to be mapped. The approach consists of three major steps. The first step is to partition a large mountainous area into several small mapping zones. Forest mapping is then conducted in each zone independently. At the second step, forest areas are separated from non-forest areas through a semi-automatic binary classification procedure. At the third step, forested areas are then further classified into detailed forest types by coupling Landsat ETM+ imagery and two topographic variables derived from a coarse DEM (extracted from 1:250,000 digital elevation contour layer, which are readily available). This hierarchical approach was illustrated and evaluated through a case study in Northwest Yunnan, China, a very rugged terrain in the world. Forests and non-forests were separated accurately and efficiently (the overall accuracy is 0.97 and Khat value is 0.94 of whole area). It was found that the inclusion of the coarse topographic data improved the mapping accuracy significantly (overall accuracy from 0.74 to 0.84, from 0.76 to 0.89, from 0.78 to 0.84 in three test areas, respectively), and that the difference in accuracy between the use of coarse DEM data and the use of fine DEM data for the study area is not significant (overall accuracy from 0.84 to 0.86). The results indicate that the hierarchical approach, coupled with coarse DEM information, is effective in increasing the accuracy of forest mapping over very rugged terrains when high quality digital elevation models are not available. 相似文献
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为获取永平县4个森林防火瞭望台观测到的可见区域面积等数据,在ArcGIS10.2下采用ArcMap10.2的3D分析工具和其它地理处理工具,基于永平县等高线数据生成DEM用于可见性分析获取瞭望观测可见区域面积;下载ASTER GDEM V2版的DEM数据用于天际线分析获取瞭望观测视线覆盖范围。分析结果表明:瞭望台可直接瞭望观测到的可见面积占永平县域面积的19.7%,县域面积均在其瞭望观测视线覆盖范围内,通过瞭望台可直接瞭望观测或间接监测到全县林火情况。 相似文献
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文章研究基于R2V和ArcGIS9.3软件,以赤峰市松山区城子乡1∶10000地形图为基础材料,通过R2V软件提取等高线,在ArcGIS软件里生成DEM及坡度、坡向图,经分析得出:这种方法制作DEM和坡度坡向图,设备简单,投入成本低,速度快,数据容易更新,但应注意制作过程中的精度和数据完整性;从DEM看出,城子乡地势总体西高东低,自东向西呈阶梯状地势逐渐升高;由坡度分析得知:城子乡15°以下土地主要分布于中东部地区,15°~25°土地主要分布于中西部地区,比较集中,城子乡25°以下土地面积33548hm2,占土地总面积的94%;由坡向分析得知:城子乡无坡向、东南、正南和西南坡向土地面积18787.8 hm2,占土地总面积的52.48%,其分布范围广,主要位于中东部地区。因此,适宜于开发为农业用地的潜力较大。 相似文献