作者简介：武文娇（1990-）,女,山西大同人,硕士生,研究方向为DEM数据在黄土高原地区的应用。E-mail: wuwenjiao0653@link.tyut.edu.cn
本文以山西省为实验区,基于ICESat/GLA14测高数据对SRTM1 DEM和ASTER GDEM V2数据的垂直精度进行了对比,分析了其在坡度、土地利用类型和地貌类型中的误差分布情况,并基于地形剖面方法分析了2种DEM数据在地形表达上的差异。研究结果表明：① 在垂直精度上,SRTM1 DEM数据要明显高于ASTER GDEM V2数据,其绝对误差均值分别为4.0 m和7.8 m,标准偏差分别为6.0 m和10.7 m,均方根误差分别为6.1 m和10.7 m。② 这2种DEM数据的精度受坡度影响严重,随坡度值的升高误差增大;SRTM1 DEM的绝对误差均值、标准偏差和均方根误差在水田最小,在林地最大,而ASTER GDEM V2的这3种误差在居民用地最小,在林地最大;SRTM1 DEM 和ASTER GDEM V2的绝对误差均值、标准偏差和均方根误差在平原地区最小,在大起伏山地最大。③ 在平原和台地地区,ASTER GDEM V2数据高程值有异常波动,SRTM1 DEM在起伏山地存在对山谷过高估计。总体上,SRTM1 DEM比ASTER GDEM V2对地形的表达准确,与ICESat/GLA14对地形的描述基本相一致。
Taking Shanxi Province as the research area, this paper compared the vertical accuracy of SRTM1 DEM and ASTER GDEM V2 data based on ICESat/GLA14 altimetry data. Firstly, error values for these two DEM datasets were acquired by taking ICESat/GLA14 data as the real data, and their error parameters were also calculated, such as mean error (ME), absolute mean error (AME), standard deviation (STD) and root mean square error (RMSE). Then, the error distribution of these two DEM datasets were analysed within the classes of slope, land use type and landform type. Finally, based on topographic profile method, the vertical error differences between these two DEM datasets in topographic types were analysed. The research results showed: (1) The vertical accuracy of SRTM1 DEM data is significantly higher than that of ASTER GDEM V2 data. The RMSE values of SRTM1 DEM and ASTER GDEM V2 are 6.1 m and 10.7 m, respectively. (2) Error analysis based on slope factor showed that the vertical accuracy of these two DEM datasets is affected seriously by the slope, and the error value increases with the increase of the slope value. Error analysis based on land use factor showed that the AME, STD and RMSE values of SRTM1 DEM are the lowest in paddy field, the highest in forestland, and the three error parameters of ASTER GDEM V2 are the lowest in building and the highest in forestland. Error analysis based on landform type factor showed that the AME, STD and RMSE values of SRTM1 DEM and ASTER GDEM V2 data are the lowest in the plain area, and the highest in large fluctuation mountain area. (3) On the selected topographic profiles in plain and terrace areas, the elevation value of ASTER GDEM V2 data have abnormal fluctuations. SRTM1 DEM data is too high for the estimation of valley. Overall, SRTM1 DEM is more accurate than ASTER GDEM V2 for terrain representation, which is basically consistent with ICESat/GLA14.
数字高程模型（Digital Elevation Model,DEM）作为描述地面高程信息的基础数据,被广泛用于地形地貌、土壤、地质灾害、气候与气象和水文等研 究[1-3]。SRTM（Shuttle Radar Terrain Mission）和ASTER GDEM（Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model）是覆盖范围最广的全球免费高精度DEM数据,应用十分广泛,因此对其精度的评价至关重要。目前,对这2种DEM数据精度的评价研究已有很多,其方法主要有2种：① 与高精度的高程点对比,对其进行精度评价,如与GPS等高精度实测点[4-6]、地形图提取的高程控制点[7-9]以及ICESat等雷达测高数据[10-13]相比较;② 通过与高精度DEM数据进行比较,对其精度进行评价,如通过与大比例尺地形图生成的DEM进行对比等[14-17]。SRTM DEM的精度易受雷达后向散射的影响,地形起伏或是植被覆盖等都会影响其精度,而ASTER GDEM通过对立体影像对解译获得,其精度易受云或是地表建筑等影响[10],所以对这2种DEM数据误差的分析,主要有通过目视对比的方法、通过与高精度DEM提取的地形要素或是水文要素进行对比[17]、基于地形因子（如海拔、坡度、地形起伏度等）、土地利用类型和植被覆盖度等分析其误差的分布情况[9],或是通过提取DEM的地形剖面分析其对地形表达的准确度等[4,15]。
SRTM DEM数据之前发布的4个版本在美国境外的分辨率都是90 m,现在http://earthexplorer.usgs.gov/网站上提供了美国境外分辨率为30 m的SRTM1 DEM数据,对其精度的研究较少,所以有必要对SRTM1 DEM和分辨率为30 m的ASTER GDEM V2数据进行精度对比。而山西境内陆形起伏不平,地貌类型复杂多样,因此本文利用ICESat/GLA14测高数据,对山西省境内的SRTM1 DEM和ASTER GDEM V2数据进行垂直精度的对比。基于坡度、土地利用类型和地貌类型对其误差分布进行分析,并通过提取在特定地貌类型中的地形剖面,对这2种数据对地形表达的准确程度进行分析,从而得出SRTM1 DEM数据与ASTER GDEM V2数据之间的精度对比情况,为这2种数据的更广泛应用提供一定参考。
山西省位于中国中部,东靠太行山,西依吕梁山,中有大同、忻定、太原、临汾和运城五大盆地,地理坐标为34°34′~40°43′N,110°14′~114°33′E,与河北、河南、陕西和内蒙古相邻。山西是典型的黄土覆盖的山地高原,其地势东北高西南低,大部分地区海拔达到1500 m以上,境内陆势起伏不平,地貌类型复杂多样,山多川少,山地分布面积占全省总面积一半以上,平原、台地、丘陵所占面积依次减 少[18],其海拔分布见
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图1 山西省SRTM1 DEM和ASTER GDEM V2数据 Fig. 1 SRTM1 DEM and ASTER GDEM V2 data in the study area |
ICESat/GLA14数据下载自美国国家冰雪数据中心,数据版本为34,从2003-2009年共19期数 据[19]。ICESat以Topex/Poseidon椭球体和EGM96大地水准面为参考。ICESat是监测极地冰盖质量变化、获取冰盖总量以及海平面变化的重要数据,与其他雷达测高数据相比,ICESat具有覆盖范围广、垂直分辨率高、采样密集等特点[20],其到达地面的激光脉冲可以形成约直径70 m的光斑,光斑之间距离约172 m,地面垂直精度很高,可达到15 cm左右[21],ICESat数据自发布以来得到了广泛的应用。
航天飞机雷达地形测绘使命（Shuttle Radar Topography Mission,SRTM）由美国太空总署（NASA）和国防部国家测绘局（NIMA）联合测量,由美国发射的“奋进”号航天飞机上搭载SRTM系统完成,获取了地球表面北纬60°到南纬56°之间80%以上的陆地表面雷达影像数据。SRTM地形数据按精度可以分为SRTM1和SRTM3,分别对应的分辨率精度为30 m和90 m数据,其以WGS84/EGM96为空间参考。本文使用SRTM1 Arc-Second Global（30 m）数据,下载网址为http://earthexplorer.usgs.gov/。
ASTER GDEM（先进星载热辐射和反射仪全球数字高程模型）是根据NASA的新一代对地观测卫星Terra的详尽观测结果制作完成的,数据覆盖范围为北纬83°到南纬83°之间的所有陆地区域,达到了地球陆地表面的99%,其全球空间分辨率约为30 m,垂直分辨率为20 m,空间参考为WGS84/EGM96。目前共有两版数据,第一版在2009年发布,本文研究所用数据为第二版,于2011年10月发布,ASTER GDEM V2版采用了一种先进的算法对V1版GDEM影像进行了改进,提高了数据的空间分辨率精度和高程精度。数据来源于中国科学院计算机网络信息中心地理空间数据云平台（http://www.gscloud.cn）。
土地利用类型数据通过遥感解译获得,主要采用中国科学院地理科学与资源研究所2010年所建立的土地资源分类系统。地貌类型数据来自中国1:100万数字地貌分类体系中的第1层基本地貌类型数据,是通过对Landsat的TM/ETM+遥感影像解译和GIS建库的方法,参考DEM数据和1:25万基础底图等数据,使用ArcGIS软件解译完成[22]。
首先,利用NSIDC（National Snow and Ice Data Center）提供的转换工具从ICESat的原始文件中提取ICESat测高数据。ICESat测高数据采用Topex/Poseidon椭球体,而SRTM和ASTER GDEM数据是采用WGS84椭球体,WGS84椭球体和Topex/Poseidon椭球体下的高程差在70~71 cm之间,虽然这个差异随纬度变化,但变化量非常小,可以忽略。为了将ICESat测高数据、SRTM和ASTER GDEM数据统一到相同的空间参考,本文将ICESat数据的高程值减去70 cm得到WGS84椭球体下的高程值[12,23]。
然后,利用ArcGIS 10.2 3D分析中的Add Surface Information工具提取ICESat点位置对应的SRTM 和ASTER GDEM数据的高程值,以ICESat高程为标准高程值,计算2种DEM数据的垂直误差,并以±50 m为阈值,对ICESat数据进行粗差的剔除。最后一共有343 254个点参与2种DEM数据的精度评价,ICESat数据轨道见
因坡度、土地利用类型和地形起伏对DEM数据的精度都有影响[6,9-10],所以基于这些因素分析DEM数据的误差分布很有必要。因此,本文分别提取剔除粗差后的ICESat点对应的坡度、土地利用类型和地貌类型（主要根据地形起伏划分）,来分析SRTM和ASTER GDEM数据的精度情况。
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图2 山西省ICESat/GLA14数据分布 Fig. 2 ICESat/GLA14 data in the study area |
为了评价SRTM和ASTER GDEM数据的垂直精度,对ICESat测高数据、SRTM和ASTER GDEM数据的基本参数进行统计,统计参数包括最大值、最小值、平均值和标准偏差;然后分别对ICESat与SRTM和ASTER GDEM之间的高程差进行统计,统计参数包括平均误差、绝对误差均值、标准偏差、均方根误差,其中平均误差可以反映2种DEM数据的系统误差,绝对误差均值可以防止平均误差计算时正负相抵的情况,反应误差的绝对大小,标准偏差对于特大和特小误差非常敏感,均方根误差可以反映误差的总体大小。最后,计算2种DEM数据的误差频率分布。
基于坡度、土地利用类型和地貌类型影响因子分析SRTM和ASTER GDEM数据的垂直误差分布情况：
（1）以小于等于3°、3~8°、8~15°、15~25°和大于25°对坡度进行分级,然后基于坡度统计SRTM和ASTER GDEM数据的误差分布,并进行比较分析。
（2）以旱地、水田、草地、林地、水域、居民用地和未利用土地这7种类型分别统计SRTM和ASTER GDEM数据的误差分布。
（3）基于地形起伏度提取的地貌类型,分为平原（<30 m）、台地（30 m）、丘陵（<200 m）、小起伏山地（200~500 m）、中起伏山地（500~1000 m）和大起伏山地（1000~2500 m）,分别统计SRTM和ASTER GDEM数据在这些地貌类型中误差的分布情况。
通过提取DEM的地形剖面,可以分析DEM的水平位置偏差和对地形的描述误差[24-25]。根据山西省的6种基本地貌类型,分别在平原、台地、丘陵、小起伏山地、中起伏山地和大起伏山地中选取了6段ICESat轨道,如
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图3 山西省地貌类型和剖面位置 Fig. 3 Landform type and profile location in the study area |
ICESat、SRTM和ASTER GDEM高程值基本参数的统计结果见
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表1 ICESat、SRTM1 DEM和ASTER GDEM V2的统计数据的比较 Tab. 1 Comparison of statistical values among the ICESat, SRTM1 DEM and ASTER GDEM V2 |
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表2 基于坡度的SRTM1 DEM和ASTER GDEM V2的误差分布（m） Tab. 2 Error distribution of SRTM1 DEM and ASTER GDEM V2 based on slope (m) |
以ICESat的高程为真值,得到的SRTM和ASTER GDEM数据的垂直误差基本参数的统计结果见
（1）基于坡度的精度分析
基于坡度对SRTM和ASTER GDEM数据的误差参数的统计结果见
（2）基于土地利用类型的精度分析
基于土地利用类型对SRTM和ASTER GDEM数据的误差参数的统计结果见
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表3 基于土地利用类型的山西省SRTM1 DEM和ASTER GDEM V2的误差分布（m） Tab. 3 Error distribution of SRTM1 DEM and ASTER GDEM V2 based on Land use type (m) |
（3）基于地貌类型的精度分析
基于地貌类型对SRTM和ASTER GDEM数据的误差参数的统计结果见
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表4 基于地貌类型的山西省SRTM1 DEM和ASTER GDEM V2的误差分布（m） Tab. 4 Error distribution of SRTM1 DEM and ASTER GDEM V2 based on landform type (m) |
基于ICESat轨道提取的SRTM和ASTER GDEM数据的地形剖面见
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图4 SRTM和ASTER GDEM的误差频率分布 Fig. 4 Error frequency distribution of SRTM and ASTER GDEM |
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图5 山西省SRTM1 DEM和ASTER GDEM V2的地形剖面图 Fig. 5 The topographic profiles of SRTM1 DEM and ASTER GDEM V2 |
本文通过利用高精度的ICESat/GLA14雷达测高数据,对山西省的SRTM1 DEM和ASTER GDEM V2数据进行垂直精度的对比分析,得出以下结论：
（1）在山西省境内,SRTM1 DEM和ASTER GDEM V2数据的总体平均误差分别为0.2 m和0.1 m,绝对误差均值分别为4.0 m和7.8 m,均方根误差分别为6.1 m和10.7 m, SRTM1 DEM数据的垂直精度明显高于ASTER GDEM V2数据。山西山地和丘陵居多,地势起伏大,对于平原为主的地区,这2种DEM数据的质量可能会优于本文的结果。
（2）SRTM1 DEM和ASTER GDEM V2数据的垂直精度受坡度、土地利用类型和地貌类型影响严重。坡度越大,数据精度越差,在坡度大于25°后,SRTM1 DEM的均方根误差达到了10.4 m,而ASTER GDEM V2达到了15.0 m;由于SRTM1 DEM和ASTER GDEM V2数据的生成原理不同,其数据质量受地类影响也不同,SRTM1 DEM的均方根误差在水田最小,ASTER GDEM V2的均方根误差在居民用地最小,而且ASTER GDEM V2数据在水域的误差较大,这2种数据受植被覆盖的严重影响,在林地的精度最差;SRTM1 DEM 和ASTER GDEM V2数据在平原地区精度最好,随地形起伏的加剧,误差逐渐增大;从提取的地形剖面可以发现,ASTER GDEM V2数据存在较多异常的高程值,在较平坦的平原或台地地区,高程异常的波动非常明显,对于地形表达的准确性比SRTM1 DEM数据差。
（3）本文对SRTM1 DEM和ASTER GDEM V2数据精度的分析以及误差分布情况的分析结果可以为这2种DEM数据的应用提供一定参考。应用DEM数据时应考虑其所属区域的地形、地类和地貌特征对数据质量的影响,不同的地形、地类和地貌数据精度差异很大,对于地势平坦的地区,使用SRTM1 DEM数据可能更为可靠。
The authors have declared that no competing interests exist.
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[本文引用:1]
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[本文引用:]
[JCR: 1.752][CJCR: 1.21]
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以福建省1:10万的DLG(Digital Line Graphic,数字线划图)和DEM(Digital Elevation Model,数字高程模型)为基础,在ArcGIS软件支持下,依据坡度和面积组合指标,将福建省地貌形态单元分为平缓地和山丘地;提取地形图中水系与等高线的高程点交集,构建了福建省地方相对基准面,并以流域水文分析方法提取了山丘地地貌形态实体单元;把平缓地和山丘地貌形态实体单元分别与地方侵蚀基准面叠加,参照"中国1:100万地貌制图规范",将福建省地貌形态类型分为平地、台地、低丘、高丘、低山、中山。研究结果表明:该方法符合福建传统地貌分类体系,能够较好快速实现平缓地与山丘地、平地(平原)与台(阶)地的自动划分,有效地提取山丘地貌形态实体单元的界线。
DOI:10.3724/SP.J.1047.2013.00075
[本文引用:1]
[CJCR: 0.946]
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This study evaluates the quality of the Advanced Spaceborne Thermal Emission Radiometer-Global Digital Elevation Model version 2 (ASTER GDEM2) in comparison with the previous version (GDEM1) as well as the Shuttle Radar Topographic Mission (SRTM) DEM and topographic-map-derived DEM (Topo-DEM) using inundation area analysis for the projected location of the Karian dam, Indonesia. In addition, the vertical accuracy of each DEM is evaluated using the Real-Time Kinematic differential Global Positioning Systems (RTK-dGPS) data obtained from an intensive geodetic survey. The results of the inundation area analysis show that GDEM2 produced a higher maximum contour level (MCL) (64 m) than did GDEM1 (55 m), and thus, GDME2 has a better quality. In addition, the GDEM2-derived MCL is similar to those produced by SRTM DEM (69 m) and Topo-DEM (62 m). The improvement in the contour level in GDEM2 is believed to be related to the successful removal of voids (artifacts) and anomalies present in GDEM1. However, our RTK-dGPS results show that the vertical accuracy of GDEM2 is much lower than that of GDEM1 and the other DEMs, which is contradictory to the accuracy stated in the GDEM2 validation document. The vertical profiles of all DEMs show that GDEM2 contains a comparatively large number of undulation effects, thereby resulting in higher root mean square error (RMSE) values. These undulation effects may have been introduced during the GDEM2 validation process. Although the results of this study may be site-specific, it is important that they be considered for the improvement of the next GDEM version.
DOI:10.3390/rs4082419
[本文引用:2]
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The freely available ASTER GDEM ver2 was released by NASA and METI on October 17, 2011. As one of the most complete high resolution digital topographic data sets of the world to date, the ASTER GDEM covers land surfaces between 83N and 83S at a spatial resolution of 1 arc-second and will be a useful product for many applications, such as relief analysis, hydrological studies and radar interferometry. The stated improvements in the second version of ASTER GDEM benefit from finer horizontal resolution, offset adjustment and water body detection in addition to new observed ASTER scenes. This study investigates the absolute vertical accuracy of the ASTER GDEM ver2 at five study sites in China using ground control points (GCPs) from high accuracy GPS benchmarks, and also using a DEM-to-DEM comparison with the Consultative Group for International Agriculture Research Consortium for Spatial Information (CGIAR-CSI) SRTM DEM (Version 4.1). And then, the results are separated into GlobCover land cover classes to derive the spatial pattern of error. It is demonstrated that the RMSE (19m) and mean (-13m) values of ASTER GDEM ver2 against GPS-GCPs in the five study areas is lower than its first version ASTER GDEM ver1 (26m and -21m) as a result of the adjustment of the elevation offsets in the new version. It should be noted that the five study areas in this study are representative in terms of terrain types and land covers in China, and even for most of mid-latitude zones. It is believed that the ASTER GDEM offers a major alternative in accessibility to high quality elevation data.
DOI:10.5194/isprsannals-I-4-181-2012
[本文引用:]
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Digital Elevation Model (DEM) is a quantitative representation of terrain and is important for Earth science and hydrological applications. DEM can be generated using photogrammetry, interferometry, ground and laser surveying and other techniques. Some of the DEMs such as ASTER, SRTM, and GTOPO 30 are freely available open source products. Each DEM contains intrinsic errors due to primary data acquisition technology and processing methodology in relation with a particular terrain and land cover type. The accuracy of these datasets is often unknown and is non-uniform within each dataset. In this study we evaluate open source DEMs (ASTER and SRTM) and their derived attributes using high postings Cartosat DEM and Survey of India (SOI) height information. It was found that representation of terrain characteristics is affected in the coarse postings DEM. The overall vertical accuracy shows RMS error of 12.62m and 17.76m for ASTER and SRTM DEM respectively, when compared with Cartosat DEM. The slope and drainage network delineation are also violated. The terrain morphology strongly influences the DEM accuracy. These results can be highly useful for researchers using such products in various modeling exercises.
DOI:10.1016/j.jag.2012.09.004
[本文引用:2]
[JCR: 3.93]
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The digital elevation model (DEM) produced by the Shuttle Radar Topographic Mission (SRTM) has provided important fundamental data for topographic analysis in many fields. The recently released global digital elevation model (GDEM) produced by the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) has higher spatial resolution and wider coverage than the SRTM3 DEM, and thus may be of more value to researchers. Taking two typical study areas—the Loess Plateau and the North China Plain of China—as an example, this article assesses the accuracy of the SRTM3 DEM and ASTER GDEM by collecting ground control points from topographical maps. It is found that both the SRTM3 DEM and the ASTER GDEM are far more accurate for the North China Plain than for the Loess Plateau. For the Loess Plateau, the accuracy of the ASTER GDEM is similar to that of the SRTM3 DEM; whereas for the North China Plain, it is much worse than that of the SRTM3 DEM. Considering the negative bias of the ASTER GDEM for flat or gentle regions, we improve its accuracy by adding the difference of the mean value between the SRTM3 DEM and ASTER GDEM for the North China Plain; then, the root mean square error (RMSE) of ±7.9502m from the original ASTER GDEM is improved to ±5.26 m, which demonstrates that it is a simple but useful way to improve the accuracy of the ASTER GDEM in flat or gentle regions.
DOI:10.1080/01431161.2010.532176
[本文引用:1]
[JCR: 1.724]
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| [8] |
Abstract In last few years, Digital Elevation Models have established much more imperative due to their diverse applications and utility in the fields of Terrain analyses, in geomorphology etc. Because of their inevitability, DEMs with reasonable accuracy and at higher spatial resolutions are being generated by different organizations worldwide, e.g. Cartosat DEM of Indian Space Research Organization (30m), Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) Global Digital Elevation Model (30m) and SRTM (90m and 30m). In the present study, specific areas have been selected based upon the terrain ruggedness i.e. Himalayan Kanchenjunga area (highly rugged terrain), Lalitpur area of Uttar Pradesh district (Moderately rugged terrain) and Roorkee area of Uttarakhand (almost flat terrain). Followed by a statistical comparison made between Cartosat-DEM (30m), ASTER-GDEM (30m) and SRTM DEM (30m) for the three regions of India. Topographic maps for the three regions have also been used to compare spots height with corresponding values in Cartosat-DEM, ASTER-GDEM and SRTM-DEM.
[本文引用:]
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先进星载热发射和反射辐射仪全球数字高程模型(ASTER GDEM)作为土地利用领域研究的重要基础数据,其精度对研究结果的准确性起到了重要作用.以连云港为例,应用地理信息系统(GIS)空间统计分析方法,选取高程互差最大最小值、均值、中误差、互差频率分布等指标,分析了不同土地利用类型的ASTER GDEM数据误差分布.结果表明:草地、水田、旱地、采矿等土地类型的精度较高,裸地、林地、园地、风景特殊等土地类型的数据误差较大;水域内的AS-TER GDEM具有一定系统误差;采矿用地包括大量盐田,多分布于沿海平坦区域,ASTERGDEM数据误差较小;土地利用类型综合反映区域地形地势及植被类型等因素,其与ASTERGDEM数据精度的关系符合地形地势与ASTER GDEM数据精度关系.本研究对连云港及其他地区的ASTER GDEM数据质量评估及修正具有指导意义.
[本文引用:3]
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The new Global Digital Elevation Model (GDEM v2) has been available since 17 October 2011. With a resolution of approximately 3002m, this model should provide more accurate information than the latest version of Shuttle Radar Topographic Mission (SRTM v4) with a resolution of 9002m outside of the USA. The accuracies of these two recently released digital elevation models (DEMs) were assessed over the Altiplano watershed in South America using ICESat/GLAS data (Ice, Cloud and Land Elevation Satellite/Geoscience Laser Altimeter System). On the global scale, GDEM v2 is more accurate than SRTM v4, which presents a negative bias of approximately 8.802m. Strong correlations between the DEMs’ accuracies and mean slope values occurred. Regarding land cover, SRTM v4 could be more accurate or easier to correct on a smaller scale than GDEM v2. Finally, a merged and corrected DEM that considers all of these observations was built to provide more accurate information for this region. The new model featured lower absolute mean errors, standard deviations, and root mean square errors relative to SRTM v4 or GDEM v2.
DOI:10.1080/01431161.2014.999166
[本文引用:3]
[JCR: 1.724]
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| [11] |
[本文引用:]
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| [12] |
航天飞机雷达地形测绘(shuttle radar topography mission,SRTM)和先进星载热发射和反射辐射成像仪全球数字高程模型(advanced spaceborne thermal emission and reflection radiometer global digital elevation model,ASTER GDEM)提供了全球覆盖面积最广的数字高程模型(digital elevation model,DEM)数据,但其高程精度还未得到充分验证,传统地面测量方法很难适用于验证大面积范围的DEM精度.以冰、云和陆地高程卫星/地学激光测高系统(ICESat/GLAS)高程数据为参考,综合利用地理信息系统(geographic information system,GIS)空间分析、三维可视化与统计分析方法,对中国典型低海拔沿海平原地区和高海拔山地的两种DEM数据高程精度进行了对比分析.结果表明,高程值小于20m的低海拔地区,SRTM高程精度达到2.39m,ASTER GDEM的精度达到4.83m,均远远高于这两种数据的标称精度;而在西南山地,这两种DEM的精度大约为20m,与标称精度相当.最后,建立了ICESat/GLAS与SRTM和ASTER GDEM的一元线性回归模型,该模型具有较高的拟合度和显著线性关系,可用于改善这两种DEM的高程精度.
DOI:10.3799/dqkx.2013.087
[本文引用:1]
[CJCR: 1.071]
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| [13] |
[本文引用:1]
[CJCR: 0.932]
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| [14] |
针对SRTM3DEM数据的误差研究在黄土高原比较薄弱的问题,该文采用基于1：5 000地形图生成精确DEM数据的方法,对最新版的SRTM3DEM V4数据在黄土高原典型地貌区的误差分布进行了研究;并对研究区内典型黄土地貌类型（黄土塬、黄土梁和黄土峁）的误差分布进行了分析,从而获取SRTM3DEM V4数据在黄土高原地区的误差分布规律。研究结果表明：SRTM3DEM V4数据误差较大,且与坡度分布密切相关;黄土塬与黄土梁的误差相似,它们均与黄土峁有明显差异。研究结果对基于SRTM DEM数据的数字地形分析与相关地学研究具有一定意义。
DOI:10.16251/j.cnki.1009-2307.2016.02.014
[本文引用:1]
[CJCR: 0.603]
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| [15] |
[本文引用:1]
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| [16] |
This paper evaluates the quality characteristics of existing versions of 3-arc-second SRTM and 1-arc-second GDEM over Anji County, Zhejiang, China using reference elevations from a high-quality 1:10 k topographic map. Results show that SRTM has higher accuracy (RMSE =12.44 m) than GDEM (RMSE=14.20 m for Version 1, 12.76 m for Version 2); however, unsatisfactory void filling and an overall 1/2 pixel shift exits in SRTM version 4.1. Although spurious elevations over omitted water bodies still persist, GDEM Version 2 demonstrated significant improvement over Version 1. Accuracies of both SRTM and GDEM decrease on steeper slopes. Aspect also influences both the magnitude and the sign of errors. DEM accuracy in non-forested areas is considerably higher than that in forested areas. SRTM version 4.1 and GDEM version 2 possessed actual spatial resolutions of 90 m, despite both of them failed to match their nominal accuracies. SRTM Version 4.1 could be the first choice, while ASTER GDEM Version 2 would be a good alternative for areas where extensive voids exist in SRTM.
DOI:10.1080/17538947.2013.807307
[本文引用:]
[JCR: 2.292]
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| [17] |
[本文引用:2]
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| [18] |
基于最新完成的中国1∶100万数字地貌数据库和山西省地图数据,利用GIS空间分析和数理统计分析方法,获得山西省多级行政单元的数字地貌类型分布特征。研究结果表明：山西省平原、台地、丘陵和山地4种地貌类型分布面积占全省总面积的比例依次是19.10%,15.77%,14.72%,50.41%;在山西省的11个地级市中,除了朔州市以平原地貌分布为主、运城市以台地地貌分布为主,其他9个城市中分布最广泛的地貌类型均是山地;在山西省的108个县中,平原作为最重要地貌类型的县有19个,台地的有17个,丘陵的有12个,山地的则有60个。
DOI:10.3969/j.issn.1007-9432.2014.04.023
[本文引用:1]
[CJCR: 0.432]
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| [19] |
The Tibetan plateau contains thousands of small and big lakes. Changes in the water level of these lakes can be an important indicator for the water balance of the Tibetan plateau, but were until now extremely difficult to monitor: performing continuous in situ measurements at a large number of lakes is not feasible because of their remoteness, while radar altimetry is only capable of monitoring large lakes. Between 2003 and 2009 the Geoscience Laser Altimeter System (GLAS) on board of the Ice, Cloud and land Elevation Satellite (ICESat) obtained world-wide elevation profiles during 18 one-month campaigns. Using the GLAS data it is possible to obtain lake levels at decimeter accuracy. Available GLAS data over the Tibetan lakes is selected by means of the MODIS lake mask. As a result, lake level variations between 2003 and 2009 of 154 lakes of over a square kilometer size could be observed. For these lakes, an analysis of annual water level trends is made, and then their yearly gained or lost water volumes are estimated. In total, an area averaged increase in lake level of 0.20m/year over the Tibetan plateau is observed between 2003 and 2009. Most of the individual lakes considered in this paper have little or no levels apparently documented, and so the ICESat data provide the first baseline measurements of these lakes in the vertical.
DOI:10.1016/j.jag.2011.09.015
[本文引用:1]
[JCR: 3.93]
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The Ice, Cloud and Land Elevation Satellite (ICESat) mission will measure changes in elevation of the Greenland and Antarctic ice sheets as part of NASA's Earth Observing System (EOS) of satellites. Time-series of elevation changes will enable determination of the present-day mass balance of the ice sheets, study of associations between observed ice changes and polar climate, and estimation of the present and future contributions of the ice sheets to global sea level rise. Other scientific objectives of ICESat include: global measurements of cloud heights and the vertical structure of clouds and aerosols; precise measurements of land topography and vegetation canopy heights; and measurements of sea ice roughness, sea ice thickness, ocean surface elevations, and surface reflectivity. The Geoscience Laser Altimeter System (GLAS) on ICESat has a 1064 nm laser channel for surface altimetry and dense cloud heights and a 532 nm lidar channel for the vertical distribution of clouds and aerosols. The predicted accuracy for the surface-elevation measurements is 15 cm, averaged over 60 m diameter laser footprints spaced at 172 m along-track. The orbital altitude will be around 600 km at an inclination of 94掳 with a 183-day repeat pattern. The on-board GPS receiver will enable radial orbit determinations to better than 5 cm, and star-trackers will enable footprints to be located to 6 m horizontally. The spacecraft attitude will be controlled to point the laser beam to within卤35 m of reference surface tracks at high latitudes. ICESat is designed to operate for 3-5 years and should be followed by successive missions to measure ice changes for at least 15 years.
DOI:10.1016/S0264-3707(02)00042-X
[本文引用:1]
[JCR: 1.806]
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本文介绍了ICESAT卫星的基本工作原理,对该卫星上的地学激光测高系统GLAS的测量原理和精度进行了分析,通过GLAS可获得冰原地形及其时变,同时也可对云及大气层的特征有更深入地了解。对GLAS的适用于冰原、冰面、陆地以及海面波形的算法进行了分析,简单介绍了对GLAS测高数据进行检核和校准,并对ICESAT数据在地学研究中的应用进行了探讨。
DOI:10.3771/j.issn.1009-2307.2005.05.010
[本文引用:1]
[CJCR: 0.603]
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| [22] |
[本文引用:1]
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The Shuttle Radar Topography Mission (SRTM) provided scientists with digital elevation data on a nearly global scale and with highly consistent accuracy. This paper compares elevation values of the C-band SRTM 30-m digital elevation model (DEM) with pointwise elevations from the Ice, Cloud, and land-Elevation Satellite (ICESat) laser altimetry for Otter Tail County, Minnesota. The accuracy of SRTM DEM is measured as a function of land covers and geomorphologic characteristics. The typical mean vertical difference between the SRTM DEM and ICESat elevations in this paper was determined in each classified land-use type and is approximately 1.5 m over bare ground, with the SRTM measuring lower elevations. Significant changes in the SRTM DEM uncertainties have been identified over different surface types classified from Landsat-7 imagery, e.g., bare ground, urban, and forested areas. Based on this result, the difference of the SRTM 30-m DEM and ICESat elevations has been removed from the DEM and made available for improved hydrological applications
DOI:10.1109/TGRS.2006.885401
[本文引用:1]
[JCR: 4.942]
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[本文引用:1]
[CJCR: 1.047]
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The Shuttle Radar Topography Mission (SRTM) collected elevation data over 80% of earth's land area during an 11‐day Space Shuttle mission. With a horizontal resolution of 3 arc sec, SRTM represents the best quality, freely available digital elevation models (DEMs) worldwide. Since the SRTM elevation data are unedited, they contain occasional voids, or gaps, where the terrain lay in the radar beam's shadow or in areas of extremely low radar backscatter, such as sea, dams, lakes and virtually any water‐covered surface. In contrast to the short duration of the SRTM mission, the ongoing Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) is continuously collecting elevation information with a horizontal resolution of 1502m. In this paper we compared DEM products created from SRTM data with respective products created from ASTER stereo‐pairs. The study areas were located in Crete, Greece. Absolute DEMs produced photogrammetricaly from ASTER using differentially corrected GPS measurements provided the benchmark to infer vertical and planimetric accuracy of the 3 arc sec finished SRTM product. Spatial filters were used to detect and remove the voids, as well as to interpolate the missing values in DEMs. Comparison between SRTM‐ and ASTER‐derived DEMs allowed a qualitative assessment of the horizontal and vertical component of the error, while statistical measures were used to estimate their vertical accuracy. Elevation difference between SRTM and ASTER products was evaluated using the root mean square error (RMSE), which was found to be less than 5002m.
DOI:10.1080/01431160600835853
[本文引用:1]
[JCR: 1.724]
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A new global elevation dataset known as G-DEM, based on the ASTER satellite imagery, will be released in late 2008. G-DEM will be the best freely available global digital elevation model (DEM) at a horizontal resolution of 1 arc second. We assess the quality of G-DEM in comparison with 3-arc-second SRTM DEM, the best current global elevation dataset. Basic geomorphometric parameters (elevation, slope and curvature) were examined for a pre-release version of G-DEM and SRTM DEM for western Japan. G-DEM has fewer missing cells than SRTM DEM, particularly in steep terrain. Also, G-DEM gives smoother and more realistic representations of lowlands, valleys, steep slopes, and mountain ridges, whereas, SRTM DEM includes many local spikes and holes, and tends to overestimate valley-floor elevation and underestimate ridge elevation. G-DEM will be commonly used in geoscientific studies, because of its higher resolution, fewer missing data, and better topographic representation than SRTM DEM.
DOI:10.1029/2008GL035036
[本文引用:1]
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高分辨率的地形数据在基础地理信息系统、地球重力场建模和大地水准面求定等工程中至关重 要.SRTM有3″×3″(SRTM3)和1″×1″(SRTM1)两种分辨率.就全球而言,SRTM3的原始数据已于2004年解密.SRTM3的高程 基准是EGM96的大地水准面,平面基准是WGS84;标称绝对高程精度是±16 m,绝对平面精度是±20 m.SRTM3的数据只覆盖60°N至54°S带状区域内的DSM.对覆盖全球的GTOPO30的DTM也作了概要介绍.
DOI:10.3969/j.issn.1671-8860.2005.11.001
[本文引用:1]
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