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1.
为利用多源DEM开发出质量更高的DEM,有必要研究数据源的误差特性,本文提出了利用傅里叶变换的多源DEM融合评价数据源的频率误差特性方法。以某实验样区为实验对象,取相同位置的航天飞机雷达地形测绘任务数字高程模型数据(SRTM DEM)与1∶50 000地面高程库数据,并以控制点数据作为参考数据,通过重采样、数据配准、系统误差消除等步骤形成融合数据源,利用傅里叶变换作低通与高通滤波融合,选择不同的截止频率得出不同的融合效果,从而判断SRTM DEM的频率误差特性。实验结果表明SRTM在采用低频信息时,融合效果优于采用高频信息,SRTM的误差更多的表现在高频特性上。 相似文献
2.
汪琳 《测绘与空间地理信息》2021,44(7):134-136,143
在分析SRTM、ASTER GDEM数据源基本特征的基础上,融合了一种直接面向河网提取的数据——SRTM-ASTER,利用SRTM数据较高的垂直分辨率修正ASTER GDEM,弥补了SRTM水平分辨率上的不足;引入Landsat-8遥感卫星数据提取真实河网,分析在有(无)河网辅助条件下融合数据的提取效果,并以总长度、支流数目、套合差为特征指标进行分析.研究结果表明:1)SRTM-ASTER数据提取的河网能综合SRTM和ASTER GDEM数据的优势,提取精度较好,但河流长度以及支流数目有所减少;2)有河网辅助的条件下,经过AGREE算法进行河网纠正以后,提取结果的精度有显著提高. 相似文献
3.
SRTM(1″)DEM在流域水文分析中的适用性研究 总被引：1，自引：0，他引：1
《国土资源遥感》2017,(2)
高精度的数字高程模型(digital elevation model,DEM)数据是流域水文分析应用的基础。美国地质调查局新发布了全球高分辨率数字高程数据产品,其空间分辨率为1″(约为30 m)。为评价该数据在流域水文分析中的适用性,以鹤壁汤河流域为实验区,以机载LiDAR DEM数据为参考,统计了SRTM(1″)数据的高程误差,分析了坡度、坡向、地表覆盖等对误差的影响;在基于地形的水文分析中,统计分析了SRTM(1″)数据误差对地形湿度指数、坡度坡长因子以及汇流动力指数等地形指数计算的影响;最后选取流域汇水区面积、最长水流路径长度、形状系数、弯曲度系数等流域特征参数对两种DEM数据提取结果进行了对比。研究表明SRTM(1″)DEM数据具有较高的精度,原始数据均方根误差为5.98 m,在消除平面位移误差后减小为4.32 m。基于地形的水文分析表明SRTM DEM与LiDAR DEM计算结果具有一定的差异,地形湿度指数平均值略高,坡度坡长因子和汇流动力指数平均值偏低,离散度偏小,这与SRTM DEM在微地貌以及高坡度地形区存在失真相关。两种DEM数据提取流域特征参数差异较小。上述研究表明SRTM DEM(1″)数据在流域水文分析中具有较大的应用潜力。 相似文献
4.
5.
为了利用航天飞机雷达地形测绘任务数字高程模型(SRTM DEM)与先进星载热反射和反辐射仪数字高程模型(ASTER DEM)的互补信息,提出基于小波分析的多源DEM数据融合方法,以我国秦岭典型高山峡谷地貌类型区为试验样区,选取相同位置的SRTM DEM与ASTER DEM数据,通过重采样、数据配准等步骤形成融合数据源;对小波分解的低频系数作基于邻域像素关联性的融合,高频系数采用像素点绝对值取大的融合,生成融合DEM。并把融合前与融合后的数据分别与1∶5万高程库数据作精度比较,总体统计与抽样检查表明融合DEM精度较源数据均得到了提高。该融合技术为应用SRTM DEM与ASTER DEM生成精度和可靠性更高的DEM产品提供了可行方案。 相似文献
6.
针对1″SRTM数据和基于1∶50 000地形图生成的DEM在黄土侵蚀区对地表形态表达能力的差异性问题,提出了一套完整的评价分析指标体系。选取陕西黄土高原6大典型黄土地貌样区,从地形属性(高程、坡度、坡向、坡长)和地形特征(山顶点、流水线、流域边界)两大方面评估了两种数据对表达黄土侵蚀区的地形表达能力。结果表明:1″SRTM对地表形态的表达能力接近1∶50 000地形图所生成的DEM,但总体上还是1∶50 000地形图所生成的DEM对地表形态的表达比较好,尤其是在地形比较破碎的地区。本文为1″SRTM数据在部分区域替代地形图生成的Hc-DEM,并用于与地学相关领域的研究提供了重要依据。 相似文献
7.
SRTM约束的无地面控制立体影像区域网平差 总被引：4，自引：2，他引：2
针对SRTM(shuttle radar topography mission)数据在平坦地形或局部区域的高程精度远远高于其标称精度的特点,研究设计了一种无地面控制条件下利用SRTM作为高程约束的立体区域网平差方法。通过构建一个较大范围区域网并匹配密集连接点,将SRTM作为连接点物方高程初值,并在平差解算过程中确保分布于地形平坦区域(根据经验,在该类区域SRTM精度较高)的连接点的物方高程严格趋近SRTM高程,最终实现大范围区域内影像高程精度的整体提升。通过以覆盖湖北省全境的资源三号卫星三线阵立体影像作为试验影像的试验验证表明,采用该平差方案,在无地面控制点条件下资源三号立体影像的高程中误差从7.2m提升到2.0m,其中地形平坦区域高程中误差1.44m,山地区域高程中误差3.0m,达到了我国1∶25 000比例尺测图应用的高程精度要求。 相似文献
8.
《测绘文摘》2006,(2)
CH20060810对SRTM3和GTOPO30地形数据质量的评估=Quality Evaluation of Topographic Data from SRTM3and GTOPO30/陈俊勇(国家测绘局)∥武汉大学学报(信息科学版).-2005,30(11).-941~944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±16m,绝对平面精度是±20m。SRTM3的数据只覆盖60°N至54°S带… 相似文献
9.
在无控制点的卫星影像正射校正中,大多采用DSM/DEM数据作为辅助数据来消除或限制因地形起伏引起的形变,然而经不同格网密度的DSM/DEM正射校正后的影像对后续处理会产生不同程度的影响,如对地物分类精度产生影响。针对这一问题,本文分别采用不同的DSM/DEM数据(China DSM 15 m、ASTER GDEM 30 m和SRTM 90 m)对资源三号影像进行正射校正,然后对正射校正后影像利用支持向量机进行分类,比较正射校正后影像结果的分类精度。结果表明:在相同重采样方法下,影像经China DSM 15 m DSM正射校正后结果的分类精度优于ASTER GDEM 30 m DEM和SRTM 90 m DEM。 相似文献
10.
获取高精度DEM是分布式水文模型开发和应用的基础,而最新发布的全球高分辨率SRTM数据在很大程度上解决了高分辨率DEM数据获取相对困难的问题,对于水文学研究具有重要意义。由于利用雷达技术获取地面高程数据技术本身的限制,SRTM原始DEM数据中存在着很多问题。本文以雪野水库区域为例,利用ASTER数据通过分析两种数据高程差异的分布特点对SRTM高程数据无效区域进行了填充,计算结果表明该方法可以提高无效数据处理结果的精度,是一种有效的获取相对完整地形数据的方法。 相似文献
11.
The Shuttle Radar Topography Mission (SRTM), the first relatively high spatial resolution near‐global digital elevation dataset, possesses great utility for a wide array of environmental applications worldwide. This article concerns the accuracy of SRTM in low‐relief areas with heterogeneous vegetation cover. Three questions were addressed about low‐relief SRTM topographic representation: to what extent are errors spatially autocorrelated, and how should this influence sample design? Is spatial resolution or production method more important for explaining elevation differences? How dominant is the association of vegetation cover with SRTM elevation error? Two low‐relief sites in Louisiana, USA, were analyzed to determine the nature and impact of SRTM error in such areas. Light detection and ranging (LiDAR) data were employed as reference, and SRTM elevations were contrasted with the US National Elevation Dataset (NED). Spatial autocorrelation of errors persisted hundreds of meters spatially in low‐relief topography; production method was more critical than spatial resolution, and elevation error due to vegetation canopy effects could actually dominate the SRTM representation of the landscape. Indeed, low‐lying, forested, riparian areas may be represented as substantially higher than surrounding agricultural areas, leading to an inverted terrain model. 相似文献
12.
Digital elevation model (DEM) data of Shuttle Radar Topography Mission (SRTM) are distributed at a horizontal resolution of 90 m (30 m only for US) for the world, Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) DEM data provide 30 m horizontal resolution, while CARTOSAT-1 (IRS-P5) gives 2.6 m horizontal resolution for global coverage. SRTM and ASTER data are available freely but 2.6 m CARTOSAT-1 data are costly. Hence, through this study, we found out a horizontal accuracy for selected ground control points (GCPs) from SRTM and ASTER with respect to CARTOSAT-1 DEM to implement this result (observed from horizontal accuracy) for those areas where the 2.6-m horizontal resolution data are not available. In addition to this, the present study helps in providing a benchmark against which the future DEM products (with horizontal resolution less than CARTOSAT-1) with respect to CARTOSAT-1 DEM can be evaluated. The original SRTM image contained voids that were represented digitally as ?140; such voids were initially filled using the measured values of elevation for obtaining accurate DEM. Horizontal accuracy analysis between SRTM- and ASTER-derived DEMs with respect to CARTOSAT-1 (IRS-P5) DEM allowed a qualitative assessment of the horizontal component of the error, and the appropriable statistical measures were used to estimate their horizontal accuracies. The horizontal accuracy for ASTER and SRTM DEM with respect to CARTOSAT-1 were evaluated using the root mean square error (RMSE) and relative root mean square error (R-RMSE). The results from this study revealed that the average RMSE of 20 selected GCPs was 2.17 for SRTM and 2.817 for ASTER, which are also validated using R-RMSE test which proves that SRTM data have good horizontal accuracy than ASTER with respect to CARTOSAT-1 because the average R-RMSE of 20 GCPs was 3.7 × 10?4 and 5.3 × 10?4 for SRTM and ASTER, respectively. 相似文献
13.
为了评价国产资源三号测绘卫星DSM数据精度,在顾及地貌类型的情况下,以涵盖平原、台地、丘陵等地貌的高海拔山区为研究案例,并以1∶1万实测地形图DEM为假定真值,以90m分辨率SRTM DEM为评价参照,从高程精度和地形描述精度两个方面,对15m分辨率ZY-3DSM进行精度评价分析。研究结果表明:ZY-3DSM高程精度优于SRTM DEM,前者高程中误差仅为后者的1/6;就地形描述精度来讲,ZY-3DSM与SRTM DEM相比,其地形描述精度更接近理论值,前者RMS Et实际值仅为理论值0.99倍,而后者的实际值却是理论值5.13倍。由此看来,ZY-3DSM数据精度整体上高于SRTM DEM。 相似文献
14.
《制图学和地理信息科学》2013,40(1):95-104
Depending on scale, topographic maps depicting the shape of the land surfaces of the Earth are produced from different data sources. National topographic maps at a scale of 1:25 000 (25K maps) produced by General Command of Mapping are used as the base map set in Turkey. This map set, which consists of approximately 5500 sheets, covers the whole country and is produced using photogrammetric methods. Digital Elevation Models (DEMs) created from these maps are also available. Recently, another data source, Synthetic Aperture Radar (SAR) interferometric data, has become more important than those produced by conventional methods. The Shuttle Radar Topography Mission (SRTM) contains elevation data with 3 arc-second resolution and 16 m absolute height error (90 percent confidence level). These data are freely available via the Internet for approximately 80 percent of the Earth's land mass. In this study, SRTM DEM was compared with DEM derived from 25K topographic maps for different parts of Turkey. The study areas, each covering four neighboring 25K maps, and having an area of approximately 600 km2, were chosen to represent various terrain characteristics. For the comparison, DEMs created from the 25K maps were obtained and organized as files for each map sheet in vector format, containing the digitized contour lines. From these data, DEMs in the resolution of 3 arc-second were created (25K-DEM), in the same structure as the SRTM DEM, allowing the 25K-DEMs and the SRTM DEM to be compared directly. The results show that the agreement of SRTM DEM to the 25K-DEM is within about 13 m, which is less than the SRTM's targeted error of 16 m. The spatial distribution of the height differences between SRTM-DEM and the 25K-DEM and correlation analysis show that the differences were mainly related to the topography of the test areas. In some areas, local height shifts were determined. 相似文献
15.
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 12.62 m and 17.76 m 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. 相似文献
16.
Validation of Indian National DEM from Cartosat-1 Data 总被引：1，自引：0，他引：1
S. Muralikrishnan Abhijit Pillai B. Narender Shashivardhan Reddy V. Raghu Venkataraman V. K. Dadhwal 《Journal of the Indian Society of Remote Sensing》2013,41(1):1-13
CartoDEM is an Indian National DEM generated from Cartosat-1 stereo data. Cartosat-1, launched in May, 2005, is an along track (aft ?5°, Fore +26°) stereo with 2.5 m GSD, give base-height ratio of 0.63 with 27 km swath. The operational procedure of DEM generation comprises stereo strip triangulation of 500?×?27 km segment with 10 m posting along with 2.5 m resolution ortho image and free—access posting of 30 m has been made available (bhuvan.nrsc.gov.in). A multi approach evaluation of CartoDEM comprising (a) absolute accuracy with respect to ground control points for two sites namely Jagatsinghpur -flat and Dharamshala- hilly; second site i.e. Alwar-plain and hilly with high resolution aerial DEM, (b) relative difference between SRTM and ASTERDEM (c) absolute accuracy with ICESat GLAS for two sites namely Jagatsinghpur-plain and Netravathi river, Western Ghats-hilly (d) relative comparison of drainage delineation with respect to ASTERDEM is reported here. The absolute height accuracy in flat terrain was 4.7 m with horizontal accuracy of 7.3 m, while in hilly terrain it was 7 m height with a horizontal accuracy of 14 m. While comparison with ICESat GLAS data absolute height difference of plain and hilly was 5.2 m and 7.9 m respectively. When compared to SRTM over Indian landmass, 90 % of pixels reported were within ±8 m difference. The drainage delineation shows better accuracy and clear demarcation of catchment ridgeline and more reliable flow-path prediction in comparison with ASTER. The results qualify Indian DEM for using it operationally which is equivalent and better than the other publicly available DEMs like SRTM and ASTERDEM. 相似文献
17.
A reference digital elevation model (DEM), produced from contour lines digitization, from topographic maps at scale 1:250.000 is used in order to assess the vertical accuracy of the SRTM DTED level 1 in Crete Island in Southern Greece. The error image interpretation revealed three types of systematic errors: (a) stripping, (b) large voids and (c) those errors resulted from the mis-registration of the Shuttle Radar Topography Mission (SRTM) imagery to the local datum. Terrain was segmented to plane regions and sloping regions. Sloping regions were segmented to aspect regions (aspect being standardized to the eight geographic directions defined in a raster/grid image). Error statistics was computed for the study area as well as the individual terrain classes. Vertical accuracy was found to be terrain class dependent. Sloping regions present greater mean error than the plane ones. Statistical tests verified that the difference in mean error between aspect regions that slope in opposite geographic directions is statistically significant. The greater mean error is observed for SW, W and NW aspect regions. The additional finishing steps applied to the SRTM dataset were not sufficient enough for the systematic errors and the terrain class dependency of the error to be corrected. The observed root-mean-square error (RMSE) for the SRTM DTED-1 of Crete do not fulfil the 16 m RMSE specification for the SRTM mission while the USA national map accuracy standards for the scale 1:250.000 are satisfied. 相似文献
18.
Terrain characterization using SRTM data 总被引：1，自引：0，他引：1
Earth’s surface possesses relief because the geomorphic processes operate at different rates, and geologic structure plays a dominant role in the evolution of landforms (Thornbury, 1954). The spatial pattern of relief yields the topographic mosaic of a terrain and is normally extracted from the topographical maps which are available at various scales. As cartographic abstractions are scale dependent, topographical maps are rarely good inputs for terrain analysis. Currently, the shuttle radar topography mission (SRTM) provides one of the most complete, highest resolution digital elevation model (DEM) of the Earth. It is an ideal data-set for precise terrain analysis and topographic characterization in terms of the nature of altimetric distribution, relief aspects, patterns of lineaments and surface slope, topographic profiles and their visualisation, correlation between geology and topography, hypsometric attributes and finally, the hierarchy of terrain sub-units. The present paper extracts the above geomorphic features and terrain character of part of the Chotonagpur plateau and the Dulung River basin therein using SRTM data. 相似文献
19.
ASTER GDEM与SRTM3高程差异影响因素分析 总被引：3，自引：0，他引：3
作为最新发布的全球地形数据,ASTER GDEM比目前常用的SRTM3数据有着更高的分辨率和更广的覆盖范围,对于相关地学分析具有重要意义。本文以华中地区为研究区域,对ASTER GDEM与SRTM3数据进行了比较,重点分析了坡度、坡向、地形起伏度、土地利用类型、植被覆盖度、生成ASTER GDEM栅格点高程数据所用的ASTER DEM影像数等因素对2种DEM数据高程差异的影响。结果表明,在研究区域内,ASTER GDEM高程比SRTM3高程平均低5.42 m,两种DEM数据高程差异的RMS值为16.90 m;ASTER GDEM与SRTM3之间的高程差异随着坡度、地形起伏度、植被覆盖度的增大而增大,而ASTER DEM影像数越大,高程差异越小;坡向、土地利用类型对高程差异也有影响。 相似文献
20.
K. S. Rao Manisha G. Naidu Jyoti Sakalley Santosh Phalke H. K. Aljassar 《Journal of the Indian Society of Remote Sensing》2005,33(2):267-276
The DEM of the Bhuj earthquake affected area of 50 x 50 km was generated using the ERS-1/2 SAR tandem data (May 15—16,1996).
Region growing algorithm coupled with path following approach was used for phase unwrapping. Phase to height conversion was
done using D-GPS control points. Geocoding was done using GAMMA software. A sample data of DEM of Shuttle Radar Topography
Mission (SRTM) of the Bhuj area is made available by DLR Germany. The intensity image, DEM and Error map are well registered.
The spatial resolution of this DEM is about 25 m with height accuracy of a few meters. The DEM derived through ERS SAR data
is prone to atmospheric affects as the required two images are acquired in different timings where as SRTM acquired the two
images simultaneously. An RMS height error of 12.06 m is observed with reference to SRTM though some of the individual locations
differ by as much as 35 m. 相似文献