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。     

数字高程模型的生产及更新

数字高程模型(DEM)是基础测绘的重要产品之一，结合测绘生产实际情况，阐述了数字高程模型生产的主要技术环节，并提出了利用已有DEM进行数据更新的方法。     

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。     

数字高程模型(DEM)成果裁切探讨

随着计算机技术及测绘产品的不断发展,数字高程模型(DEM)已成为地理信息空间系统和"数字地球"的重要组成部分。在测绘技术蓬勃发展的今天,数字高程模型(DEM)的生产已成为各生产部门较关注的问题之一,特别是近年来数字龙江地理空间框架建设一期工程对数字高程模型(DEM)产品成果的要求有很大提高,数字高程模型(DEM)成果的裁切也显得尤为重要,本文从工作中遇到的DEM成果裁切问题入手,结合笔者多年的测绘生产经验,研讨DEM成果裁切问题。     

基于DEM坡度坡向算法精度的分析研究

坡度坡向是两个最基本的地形因子,目前对DEM坡度坡向计算模型和精度存在一些不同的甚至矛盾的观点,其原因在于没有区分误差来源和分析评价方法的不同.本文对DEM坡度坡向误差进行了理论分析,并通过实验数据对相关结论进行了验证.旨在澄清目前关于坡度坡向计算模型上的矛盾结论.     

南宁市六城区数字高程模型制作及应用前景

以南宁市六城区数字高程模型制作为例,对南宁市数字高程模型的制作过程进行了系统的阐述,由此针对制作大比例尺数字高程模型提出几点建议,最后探讨了其社会经济效益和推广前景.     

基于DEM的可视频度提取与制图

首先提出可视频度的概念、分类与描述方式,着重阐述了动态观测点和动态目标点可视频度分析的理论模型.通过样区实验,介绍了可视频度提取原理和应用,并制作了可视频度专题图.     

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.     

DEM流域网络提取算法的误差特性分析

流域网络及其描述参数是一类重要的环境参数,其质量直接影响着各类地学模型和地学过程模拟的精度。在数据独立的DEM误差分析方法支持下,以比汇水面积(Specific catchment area,SCA)为计算对象,详细分析5种流域网络提取算法的误差空间分布特征。研究表明,不论何种算法,SCA误差主要集中于合水区域;不同算法的SCA频率分布随着SCA值的增加而趋于一致;SCA精度的提高有赖于DEM路径算法的改进,不同路经算法的组合可有效改善流域网络提取和分析的质量。     

Evaluation of Information Loss in Digital Elevation Models With Digital Photogrammetric Systems

Information loss is caused when a surface is sampled with a finite interval, such as in the production of a digital elevation model (DEM). This information loss can become the dominant part of the error in a DEM. The ability to quantify information loss enables guidance to be provided for an appropriate choice of grid interval and better accuracy assessment for the DEM. With the use of digital photogrammetric systems, evaluation of information loss has become much easier. This paper describes three methods of evaluating information loss. An example is given of the method which is most appropriate for use with a digital photogrammetric system, based on rock cliff surface data and the VirtuoZo system.     

Vertical accuracy assessment of freely available digital elevation models over low-lying coastal plains

The frequency of coastal flood damages is expected to increase significantly during the twenty-first century as sea level rises in the coastal floodplain. Coastal digital elevation model (DEM) data describing coastal topography are essential for assessing future flood-related damages and understanding the impacts of sea-level rise. The Shuttle Radar Topography Mission (SRTM) and Advanced Spaceborne Thermal Emission and Reflection Radiometer Global Digital Elevation Model (ASTER GDEM) are currently the most accurate and freely available DEM data. However, an accuracy assessment specifically targeted at DEMs over low elevation coastal plains is lacking. The present study focuses on these areas to assess the vertical accuracy of SRTM and ASTER GDEM using Ice, Cloud, and land Elevation Satellite, Geoscience Laser Altimeter System (ICESat/GLAS) and Real Time Kinematic (RTK) Global Positioning System (GPS) field survey data. The findings show that DEM accuracy is much better than the mission specifications over coastal plains. In addition, optical remote sensing image analysis further reveals the relationship between DEM vertical accuracy and land cover in these areas. This study provides a systematic approach to assess the accuracy of DEMs in coastal zones, and the results highlight the limitations and potential of these DEMs in coastal applications.     

1:10000数字高程模型(DEM)生产中常见问题初探

针对1:1万数字高程模型生产中出现的一些问题,在经验总结的基础上,提出解决的办法,目的在今后的工作中,遇到相同问题时少走弯路,同时能给读者以启发和帮助。     

不同软件在ASTER数据中提取DEM的精度对比

利用3个不同的软件对四川省龙门山中段ASTER 15 m分辨率的立体像对进行了DEM提取,并对其精度进行了初步评价。分别使用立体测量法和干涉测量法提取DEM,并通过检验点法和剖面线法对比分析。结果表明,利用ERDAS的干涉测量法提取出的DEM效果较好,高程精度可达30 m,对后续数据深挖掘和高层次地形分析具有应用价值。     

ASTER立体像对提取玛尔挡坝区DEM及精度评价

ASTER立体像对提取DEM已经成为近年来DEM提取研究的热点问题。本文基于ENVI软件,利用AS-TER立体像对提取青藏高原玛尔挡坝区DEM,并对其进行精度评价和误差来源分析。结果表明,利用ENVI软件提取ASTER-DEM方法可行,提取的DEM效果较好,能与地形图重叠,高程精度可达30m,而且地形较平坦地区精度高于地形陡峭地区;控制点的多少及精度、成像时的环境和气象条件、波段特性、影像空间分辨率等都影响着DEM的精度。     

Mapping from ASTER stereo image data: DEM validation and accuracy assessment

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) on-board the National Aeronautics and Space Administration's (NASA's) Terra spacecraft provides along-track digital stereo image data at 15-m resolution. As part of ASTER digital elevation model (DEM) accuracy evaluation efforts by the US/Japan ASTER Science Team, stereo image data for four study sites around the world have been employed to validate prelaunch estimates of heighting accuracy. Automated stereocorrelation procedures were implemented using the Desktop Mapping System (DMS) software on a personal computer to derive DEMs with 30- to 150-m postings. Results indicate that a root-mean-square error (RMSE) in elevation between ±7 and ±15 m can be achieved with ASTER stereo image data of good quality. An evaluation of an ASTER DEM data product produced at the US Geological Survey (USGS) EROS Data Center (EDC) yielded an RMSE of ±8.6 m. Overall, the ability to extract elevations from ASTER stereopairs using stereocorrelation techniques meets expectations.     

利用ASTER立体像对提取相对DEM及正射影像地图制作

本文探讨在PCIGeomatica软件支持下,应用四川省泸州地区ASTER立体像对数据自动提取DEM及其正射影像地图制作。通过与当地实测地形图(1∶50000)比较,表明在平坦地区ASTER DEM与实测地形图吻合很好;在高程变化较大的区域由于太阳高度、方位影响和ASTER后视成像存在着较大的叠掩和阴影效应,ASTER DEM和实测DEM存在一些差异,但总体上可以满足中小比例尺(1∶500,000到1∶1000,000)地图应用。ASTER的应用为DEM的快速提取和正射影像地图制作提供了一种新的途径。     

格网DEM地形模拟的形态保真度研究

分析了现有格网DEM地形模拟的失真现象,研究DEM地形模拟失真的根源。提出了DEM地形形态保真度的概念,探讨了建设高保真DEM必须解决的问题。     

江苏省数字高程模型制作

本文通过江苏省30 m象元数字高程模型制作这一工程实例,详细的介绍了运用ARC/INFO这一地理信息软件制作数字高程模型的方法.     

浅谈对数字高程模型的几点认识

简要介绍了数字高程模型（DEM）,结合实际阐述了DEM的采集方法、误差来源、质检方法,以及如何通过上述过程,使数字高程模型达到更高的精度要求。     

基于随机过程的格网DEM精度场模型

针对目前DEM格网精度从理论上难于统一量化描述问题,提出一种基于随机过程的格网DEM（grid digital elevation model, grid DEM）精度场模型,该模型从随机过程理论入手,借助DEM的统一插值模型,建立了DEM两类误差（噪声误差和逼近误差）的数学表达,并分析了构成DEM误差的各个分量的数学意义。与已有的模型相比,该模型实现了传统DEM两类误差的统一描述,此外,该模型适用任意插值方式生成的格网DEM的精度评价。