| 规则格网DEM局地坡面凸凹性精度分析 |
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| 引用本文： | 王春,徐燕,江岭,赵明伟.规则格网DEM局地坡面凸凹性精度分析[J].地球信息科学,2020,22(3):361-369. |
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| 作者姓名： | 王春 徐燕 江岭 赵明伟 |
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| 作者单位： | 1. 滁州学院地理信息与旅游学院,滁州 239000;2. 安徽省地理信息智能感知与服务工程实验室,滁州 239000 |
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| 基金项目： | 国家自然科学基金项目(41571398);国家自然科学基金项目(41201415);国家自然科学基金项目(41501445);安徽省自然科学基金项目(1408085MD77);安徽省自然科学基金项目(1608085QD77) |
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| 摘 要： | DEM地表形态精度分析理论与方法的建立,对DEM数据的生产和广泛应用具有重要意义。本文从局地坡面形态的凸凹性角度,剖析规则格网DEM格网点位置、格网分辨率对DEM局地坡面凸凹性的影响,以期进一步完善和发展DEM质量分析的理论与方法。论文首先阐述了DEM局地坡面凸凹性的基本概念,研究建立了规则格网DEM的局地坡面凸凹性量化分析方法,并以黄土丘陵5、10、15、25、……、155 m DEM为例,采用比较分析方法研究了局地坡面凸凹性随DEM格网点位置和格网分辨率的变化特征。研究表明:对于本研究中的1:5万DEM,10 m(跃变率≤0.3%)是其最佳的格网分辨率阈值,当DEM实际格网分辨率高于该阈值时,实际DEM与最佳格网分辨率DEM具有近乎相同的局地坡面凸凹性,主要在正地形与负地形的过渡区域会发生不同程度的坡面凸凹性变化;当DEM实际格网分辨率低于该阈值时,实际DEM的局地坡面凸凹性,会随着DEM格网点布设位置和DEM格网分辨率发生较大的不确定性变化。
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| 关 键 词： | DEM 局地坡面 凸凹性 空间关系 地表形态 黄土丘陵 误差 精度 |
| 收稿时间： | 2019-05-17 |
Accuracy Assessment of Local Slope Concave-convex Properties based on Multi-scale Gridded DEMs |
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| WANG Chun,XU Yan,JIANG Ling,ZHAO Mingwei.Accuracy Assessment of Local Slope Concave-convex Properties based on Multi-scale Gridded DEMs[J].Geo-information Science,2020,22(3):361-369. |
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| Authors: | WANG Chun XU Yan JIANG Ling ZHAO Mingwei |
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| Institution: | 1. Geographic Information and Tourism College ,Chuzhou University, Chuzhou 239000, China;2. Anhui Engineering Laboratory of Geo-information Smart Sensing and Services, Chuzhou 239000, China |
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| Abstract: | The accuracy of DEMs is the key issue for its quality and various applications. Theoretically, terrain morphology is the basis to derive the topographic information. Therefore, to establish the methodology of DEM's morphologic accuracy can promote the high-quality DEM productions and their widespread applications. Focusing on the cognition of the local slope concave-convex property, this paper analyses the influences of grid point locations and grid cell sizes on this morphological property. As such, this paper arms to further improve and develop the theory and method of DEM quality. At first, this paper introduces the basic concept of terrain morphology accuracy represented by the gridded DEM, consisting of elevation sampling accuracy and elevation relation accuracy of local points, local slope morphology accuracy, regional terrain relation accuracy and global terrain structure accuracy. Herein, the local slope morphology accuracy can be represented by the local slope concave-convex property, including three categories of flat slope, concave slope and convex slope. To quantify the concave-convex property, the error metric is defined using the multi-scale DEMs and several statistic indexes of the error metric are presented. At last, taking loess hill region as the study area and 5、10、15、25、…、155 m DEMs generated by the TIN-based method as the experimental dataset, the comparative method is applied to investigate the characteristics of the local slope concave-convex slope varied with the grid-point location and the grid cell size. The main conclusions of this research are reached as follows: (1) the morphology accuracy of DEMs must be considered in the production of high-quality DEMs. In this study, 10 m size (jumping rate is equal or lesser than 0.3%) is optimal threshold of the grid cell size for 1:50 000 DEMs. (2) When the DEM resolution is higher than the threshold, the DEM has almost the same concave-convex property with the real topography, followed by the less changes in the transition area between the positive and negative terrains. When the resolution of DEM is lower than the threshold, the local slope concave-convex property would have a significant uncertainty changed with the grid-point location and the DEM resolution. |
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| Keywords: | DEM local slope concave-convex spatial relationship terrain morphology loess hill region error accuracy |
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