基于SRTM-DEM区域地形起伏的获取及应用

 基于数字高程模型（DEM）空间分析方法，利用SRTM采集的DEM数据，提出两种获取区域地形起伏的关键技术，即高程条带法（Swath Profile）和高程阈值法（Threshold Value），并通过扩展区域地形起伏获取的技术方法，初步实现了黄土高原典型地区侵蚀量的定量化分析。     

利用插值算法填补SRTM3 DEM数据空洞的比较分析

由于雷达热噪声、斑点噪声和解缠等因素的共同影响,利用合成孔径雷达干涉测量(InSAR)技术获取的SRTM3 DEM存在高程数据空洞,严重影响了该DEM产品的应用。SRTM3 DEM数据空洞的分布一般呈现空间随机性。本文通过比较分析利用各种插值算法填补DEM数据空洞的优劣,从中选出一种最优方法来对SRTM3 DEM进行插值填补。     

利用升降轨道SAR数据获取DEM的试验研究

首先介绍了利用InSAR技术提取DEM的原理及方法,其次对利用ENVISAT卫星的升轨SAR数据和降轨SAR数据获取DEM,然后对其融合,并将融合前后的DEM与SRTM3 DEM进行比较,分析其精度。结果表明,与单独利用升轨SAR数据或降轨SAR数据获取的DEM相比,融合后的DEM能更好地显示地形起伏特征,高程精度得到明显提升,且羽化融合后的DEM精度最高,其与参考DEM─SRTM3 DEM高程差异标准差为±7.25,高程差异绝对值小于15 m的地区占95.48%。     

SRTM DEM数据空洞插值填补方法对比分析

SRTM全球数字高程模型数据目前已被广泛应用于多个领域。最新版本的SRTM DEM仍然存在较小的高程空值区域（数据空洞）和模糊区域。文章在模拟某试验区域SRTM DEM数据空洞的基础上,利用线性插值、反距离权插值、二次多项式插值、三次样条插值等DEM插值方法进行了数据空洞的插值填补试验和对比分析,结果表明在丘陵地区和空...     

基于SRTM DEM的InSAR高分辨率山区地表高程重建算法

山体的叠掩和阴影现象造成的信号去相关,一直是InSAR重建山区地表高程的瓶颈之一.为此,提出了一种新的基于粗分辨率SRTM DEM(约90m分辨率)辅助InSAR数据重建山区地表高程的方法.利用SRTM DEM模拟的干涉相位,对ERS-1/2干涉相位做去地形相位处理,得到残余相位.通过对解缠后的残余相位计算方差提取叠掩和阴影区域的噪声,并用平均相位近似恢复噪声区域的相位,然后将其转换为高程,并用SRTM DEM作高程补偿处理,从而实现地表高程重建.最后,定量比较了该方法与传统InSAR技术生成的DEM精度.实验表明,这种方法能有效提高传统InSAR技术生成地表高程的精度,这对提高星载雷达数据的使用效率具有重要意义.     

中国地区SRTM3 DEM高程精度质量评价

为揭示我国SRTM3DEM数据高程精度质量,结合已开展过SRTM3DEM高程精度质量评价工作的局部地区的研究,考虑空间分布情况,选取新疆、辽宁、山东、浙江、海南5个地区的平原、丘陵、盆地、山地等地形区域作为典型研究区,并以1∶5万DEM为假定真值、以1∶25万DEM为参照,通过DEM面误差可视化分析、DEM面误差信息熵模型、中误差模型等方法对SRTM3DEM数据高程精度质量做了分析。计算结果表明我国SRTM3DEM数据高程精度质量受地形影响并存在一定的空间差异性,同时我国范围内SRTM3DEM数据高程精度质量整体上要高于1∶25万DEM。     

中国及周边区域ASTERGDEM与SRTMDEM高程对比分析及互补修复

本文分析了ASTER GDEM和SRTM DEM的获取方式,通过对两者在中国及周边区域高程的对比分析,得出两者高程间存在系统误差,前者高程比后者平均低4.9m。ASTER GDEM在许多区域特别是水域及高山区常存在明显粗差;SRTM DEM在特别是高山区域会出现空白区域,但其有效区域层次清晰、细节分明,无明显粗差,可靠性高。经过填补及高差约束限制修复,生成了无空白区域的SRTM DEM和可靠性更高的ASTER GDEM。     

全球数字高程产品概述

随着世界各国乃至全球信息化和数字化的发展以及全球化热点问题的研究,高精度、高分辨率全球数字高程产品在广泛的应用领域中扮演着越来越重要的角色。为了方便不同用户根据个人需求选择合适的数据产品,本文首先论述了数字高程产品的精度衡量指标,并对其常用的指标进行等价描述,以便不同数字产品之间的比较分析;然后从全球化高程数据的获取方式出发,经由最初的多源数据融合,到后续基于光学立体摄影测量及合成孔径雷达干涉测量InSAR (Interferometric Synthetic Aperture Radar)的全球测图,对其发展的ETOPO、GTOPO30、GMTED2010、ASTER GDEM、AW3D30、SRTM及TanDEM-X DEM全球化数据产品的主要性质和特点进行详细介绍,并简单概括了不同数字产品的发展历程。在此基础上,本文以宁夏回族自治区吴忠市一座山脉为例,通过定性及定量对比的方式详细分析了1″及3″经纬度格网分辨率下的数字高程产品。分析表明,对于采用同一种技术手段生产的数字高程产品,AW3D30及ASTER GDEM均展现出相对丰富的地貌细节特征,均优于SRTM及TanDEM-X DEM产品,但ASTER GDEM产品颗粒效应明显,且产品精度较低;而TanDEM-X DEM是从更高分辨率产品重采样获取,因此相对平滑;就数字高程产品的高程精度而言,TanDEM-X DEM产品精度最高,其次为AW3D30及SRTM产品,均远优于由多源数据融合获取的全球数字产品。     

基于InSAR技术对西部高山地区DEM的重建

合成孔径雷达干涉测量技术是一种获取地面数字高程模型(DEM)的新技术.介绍利用InSAR获取DEM的基本流程,阐述相位解缠的理论方法以及基线估计中获取地面控制点的方法与原则,通过实验获取西部某高山地区的DEM,并与SRTM DEM作比较、分析,总结出其存在局限性的原因.     

利用InSAR技术获取高寒高海拔地区高精度DEM

本文以Sentinel-1A SLC数据为原始影像,利用InSAR技术获取新疆西天山中部高寒高海拔地区小区域DEM,将获得的DEM与常用的SRTM v4 DEM和GDEMDEM进行对比分析。结果表明：利用InSAR技术处理Sentlnel-1A SLC数据可以获得分辨率为15 m的高精度DEM,该DEM数据精度优于SRTM v4 DEM和GDEMDEM,能更好地描绘地表地形细节,可作为输入数据获取地面高精度形变信息,为工程建设和地质灾害评价提供重要的基础数据。此外,该方法对DEM数据的更新也具有重大意义。     

A practical method for SRTM DEM correction over vegetated mountain areas

Digital elevation models (DEMs) are essential to various applications in topography, geomorphology, hydrology, and ecology. The Shuttle Radar Topographic Mission (SRTM) DEM data set is one of the most complete and most widely used DEM data sets; it provides accurate information on elevations over bare land areas. However, the accuracy of SRTM data over vegetated mountain areas is relatively low as a result of the high relief and the penetration limitation of the C-band used for obtaining global DEM products. The objective of this study is to assess the performance of SRTM DEMs and correct them over vegetated mountain areas with small-footprint airborne Light Detection and Ranging (Lidar) data, which can develop elevation products and vegetation products [e.g., vegetation height, Leaf Area Index (LAI)] of high accuracy. The assessing results show that SRTM elevations are systematically higher than those of the actual land surfaces over vegetated mountain areas. The mean difference between SRTM DEM and Lidar DEM increases with vegetation height, whereas the standard deviation of the difference increases with slope. To improve the accuracy of SRTM DEM over vegetated mountain areas, a regression model between the SRTM elevation bias and vegetation height, LAI, and slope was developed based on one control site. Without changing any coefficients, this model was proved to be applicable in all the nine study sites, which have various topography and vegetation conditions. The mean bias of the corrected SRTM DEM at the nine study sites using this model (absolute value) is 89% smaller than that of the original SRTM DEM, and the standard deviation of the corrected SRTM elevation bias is 11% smaller.     

基于ICESat-2 ATLAS数据的DEM高程精度评价

为探究ASTER GDEMV3、SRTM1 DEM和AW3D30 DEM 3种开源DEM数据的高程精度,本文以高精度ICESat-2 ATLAS测高数据为参考数据,利用GIS统计分析、误差相关分析及数理统计对DEM的高程精度进行对比评价。结果表明：①AW3D30的质量最稳定;SRTM1 DEM在平原精度最高;在高原山地精度由高到低依次为AW3D30 DEM、ASTER GDEMV3、SRTM1 DEM。②DEM数据高程精度受地表覆盖影响较大,且与地形因素密切相关,在相同地表覆盖的两个研究区中DEM数据高程精度表现情况不一致,SRTM在平原地表覆盖下精度表现最好,平均误差为3.15 m,AW3D30 DEM在山地地表覆盖下精度表现最好,平均误差为7.61 m。③坡度对DEM数据的高程精度影响较大,在两个研究区3种DEM数据的高程误差均随坡度的增加而增加;坡向对DEM数据的高程精度影响较小,未发现明显的规律。     

Evaluation of digital elevation models for delineation of hydrological response units in a Himalayan watershed

This study reports results from evaluation of the quality of digital elevation model (DEM) from four sources viz. topographic map (1:50,000), Shuttle Radar Topographic Mission (SRTM) (90 m), optical stereo pair from ASTER (15 m) and CARTOSAT (2.5 m) and their use in derivation of hydrological response units (HRUs) in Sitla Rao watershed (North India). The HRUs were derived using water storage capacity and slope to produce surface runoff zones. The DEMs were evaluated on elevation accuracy and representation of morphometric features. The DEM derived from optical stereo pairs (ASTER and CARTOSAT) provided higher vertical accuracies than the SRTM and topographic map-based DEM. The SRTM with a coarse resolution of 90 m provided vertical accuracy but better morphometry compared to topographic map. The HRU maps derived from the fine resolution DEM (ASTER and CARTOSAT) were more detailed but did not provide much advantage for hydrological studies at the scale of Sitla Rao watershed (5800 ha).     

国产资源三号测绘卫星DSM数据质量评价--以高海拔山区为例

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。     

基于资源三号测绘卫星DSM的精度评估研究

作为我国首颗民用立体测绘卫星数据产品,ZY-3 DSM对于我国地学分析具有极其重要的作用。本文在顾及地貌情况前提下,选取云南省高海拔山区为试验区,辅以1∶10 000野外实测地形图DEM为参考值,将分辨率为15 m的ZY-3 DSM与90 m的SRTM DEM从高程精度和地形精度进行较为全面的数据质量比较。结果表明:ZY-3 DSM在高程精度和地形精度均有更好的表现。总体看来,ZY-3 DSM数据质量更高,具有更广泛的利用价值。     

Comparative evaluation of horizontal accuracy of elevations of selected ground control points from ASTER and SRTM DEM with respect to CARTOSAT-1 DEM: a case study of Shahjahanpur district,Uttar Pradesh,India

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.     

Application of satellite — based rainfall products and SRTM DEM in hydrological modelling of Brahmaputra basin

Hydrological modelling of large river catchments is a challenging task for water resources engineers due to its complexity in collecting and handling of both spatial and non-spatial data such as rainfall, gauge discharges, and topographic parameters. In this paper an attempt has been made to use satellite-based rainfall products such as Climatic Prediction Centre (CPC)-National Oceanic and Atmospheric Administration (NOAA) data for hydrological modelling of larger catchment where the limited field rainfall data is available. Digital Elevation Models (DEM) such as Global DEM (1 km resolution) and Shuttle Radar Topography Mission (SRTM) 3-arc second (90 m resolution) DEM have been used to extract topographic parameters of the basin for hydrological modelling of the study area. Various popular distributed models have been used in this study for computing excess rainfall, direct runoff from each sub-basin, and flow routing to the main outlet. The Brahmaputra basin, which is very complex both hydraulically and hydrologically due to its shape, size, and geographical location, has been examined as study area in this study. A landuse map derived from the satellite remote sensing data in conjunction with DEM and soil textural maps have been used to derive various basin and channel characteristics such as each sub-basin and channel slope, roughness coefficients, lag-time. Percentage of residual flows computed between observed flows and simulated flows using Global and SRTM DEMs are discussed. It is found that the topographic parameters computed using SRTM DEM could improve the model accuracy in computing flood hydrograph. Need of using better resolution satellite data products and the use of high-density field discharge observations is discussed.     

SAR卫星轨道数据精度对Doris获取DEM精度的影响研究

本文介绍了InSAR卫星轨道状态矢量内插方法,基于荷兰Delft大学开发的Doris雷达干涉软件分析了SAR卫星轨道数据误差对基线参数、参考椭球面相位、地形干涉相位和数字高程模型(DEM)精度的影响。以西藏玛尼地区为例,采用ERS1/2卫星数据,利用Doris软件,分别生成了基于欧空局(ESA)粗略轨道数据和荷兰Delft大学精密轨道数据的数字高程模型(DEM),并以SRTMDEM为基准对其精度进行了对比分析。结果表明,基于粗轨数据获取的DEM明显存在系统偏差,而基于精轨数据获取的DEM与SRTM DEM吻合的很好,相对于前者,精度提高5倍。