基于数字高程模型的鄱阳湖淹水范围制图研究

利用13幅Landsat TM/ETM+鄱阳湖区遥感影像,提取不同水位下的淹水范围,根据淹水面积与湖内7个水文站水位相关性,确定都昌水文站水位能够最好控制鄱阳湖水面范围。为了改善中低水位条件下淹水范围的制图精度,将遥感提取的水体边界作为水位等值线,插值建立鄱阳湖基于水体边界的数字高程模型(taterline-based DEM,WL_DEM),利用WL_DEM和都昌水位实现中低水位淹水范围制图。结果表明,中低水位条件下,基于WL_DEM的淹水范围制图精度都有显著提高。     

Digital Elevation Models By Laser Scanning

The TopoSys laser scanner system is designed to produce digital elevation models (DEMs) at a maximum accuracy of 0.5 m in x and y and 0.1 m in z. The regular scan pattern and the measurement frequency of 80 000 measurements per second (on average 5 measurements per m2) form the basis for high quality DEMs.
The mainly automated data processing makes it possible to generate DEMs of large areas in a short production time. The DEMs produced come into common use as basic data for different applications, some of which are water resources management, shoreline control, planning of utility lines and urban planning (simulation of noise and pollution distributions). The performance of the system is illustrated with the help of DEM sections produced with the TopoSys system.     

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.     

数字高程模型DEM精度研究

用不同地貌类型地区的实验数据对数字高程模型(规则格网DEM)的格网间距与中误差(RMSE)、平均高程、剖面曲率的关系进行研究,采用比较分析的方法,得到格网间距与中误差的数学模型,可以用通式:Y=A BX CX2表示,并且把地形因子(平均高程、剖面曲率)作为自变量,进一步分析通式中3个系数与地形因子的关系,发现两个地形因子与系数函数关系比较相似,并得到Y=A BX CX2 DX3的数学模型。由验证结果表明,所得模型效果良好。     

利用地形信息强度进行DEM地形简化研究

在对现有的DEM地形简化方法进行总结分析的基础上,提出了一种利用地形信息强度指数的DEM简化方案。首先提取DEM点位地形信息强度指数值,然后通过阈值法确定候选地形特征点重构DEM,以国家基本比例尺1∶5万DEM作为参照目标,并将重要点法和三维道格拉斯法作为对比方法,对应用该方法进行地形简化的效果进行了综合评价。实验结果表明,该方法应用于大范围DEM简化中可以有效地保留地形骨架的结构特征,同时具有较高的数值精度,可以满足不同层次的多尺度DEM建模的要求。     

Using Synthetic Aperture Radar Imagery for Flood Modelling

Airborne radar technology has traditionally been largely devoted to military applications. In recent years, applications in telecommunications, oil exploration and agriculture have proved that radar technology can also be used commercially. This paper focuses on an application of airborne radar technology in the insurance industry and describes the development of a large-scale flood risk assessment model for the River Thames. The model is based upon airborne Synthetic Aperture Radar (SAR) data and was built with commonly used Geographic Information Systems (GIS) and image processing tools. From the Orthorectified Images (ORIs) a land cover map was produced, from which a surface roughness map could be derived. A Digital Elevation Model (DEM) was processed to remove trees and other soft barriers and obtain the effective ground level. This was achieved by using standard GIS processes. The methodology may be applicable to any organisation exposed to flood risk.     

山西省高精度数字高程模型建设方案设计与实现

结合山西省高精度数字高程模型建设项目,详细介绍了利用机载激光雷达进行大面积数据获取的技术方案和数据处理关键技术,为进行大面积机载激光雷达数据获取和处理积累了丰富的经验,该项目的建成,满足了省内各类不同行业用户以及科学研究机构对我省精密地表数据的需求。     

非量测数码影像在航测成图中的应用

如何加速成图周期,快速、高效地生产各种地理信息产品是摄影测量应用研究的主要内容.本文介绍了非量测数码航摄影像在全数字摄影测量工作站上进行地理信息产品生产的技术方法和工作流程,研究了关键技术环节.     

数字高程模型(DEM)和数字线划图(DLG)的坐标转换方法

介绍数字高程模型(DEM)、数字线划图(DLG)由1980西安坐标系向2000国家大地坐标系的高精度、无缝隙转换方法,可以满足各种比例尺、任意范围数字产品的坐标转换.利用实例数据通过大量试验分析、研究,证明该转换方法是正确、可行的.     

全球高分辨率数字高程模型研究进展与展望

简要介绍了数字高程模型（digital elevation model,DEM）的起源与定义,根据4种不同的观测平台分类介绍了DEM数据获取方法,给出目前国际上发布的高分辨率全球DEM的主要性质和特点。重点介绍了9大类全球DEM,分析了DEM质量评估相关的评定方法和精度指标。论述了DEM在地质灾害监测、海岸带脆弱性分析方面的应用,以美国地质勘探局和德国航空太空中心正在开展的DEM项目为例,讨论了高精度、高分辨率全球同质DEM和地形测深高程模型的最新需求,最后总结展望全球高分辨率DEM的发展趋势。     

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.     

基于Clementine和ULCN2005的月球测图研究

为使用嫦娥一号三线阵光学影像进行月球测图,本文研究月球测图的特殊性问题及其解决方案,提出基于Cle-mentine卫星影像数据和ULCN 2005月球控制网进行月球测图的方法,应用商业数字摄影测量软件和自主研发的辅助软件系统进行了月球测图实验.该实验选择了月球近南极的一块区域(W109.7°～W163.4°,S69.3°～S84.2°,面积约1.5×105km2),采用10个轨道的60景Clementine的UVVIS影像、408个ULCN 2005控制点(其中56个作为检查点)和1 337个连接点,建立该区的DTM和地形图,水平中误差和垂直中误差分别为98.639 m(0.19pixel)和1 003.751 m(1.93pixel).论证基于嫦娥数据生成月球DTM和地形图的可行性.     

Quality Assessment Of Digital Surface Models Generated From IKONOS Imagery

The growing applications of digital surface models (DSMs) for object detection, segmentation and representation of terrestrial landscapes have provided impetus for further automation of 3D spatial information extraction processes. While new technologies such as lidar are available for almost instant DSM generation, the use of stereoscopic high-resolution satellite imagery (HRSI), coupled with image matching, affords cost-effective measurement of surface topography over large coverage areas. This investigation explores the potential of IKONOS Geo stereo imagery for producing DSMs using an alternative sensor orientation model, namely bias-corrected rational polynomial coefficients (RPCs), and a hybrid image-matching algorithm. To serve both as a reference surface and a basis for comparison, a lidar DSM was employed in the Hobart testfield, a region of differing terrain types and slope. In order to take topographic variation within the modelled surface into account, the lidar strip was divided into separate sub-areas representing differing land cover types. It is shown that over topographically diverse areas, heighting accuracy to better than 3 pixels can be readily achieved. Results improve markedly in feature-rich open and relatively flat terrain, with sub-pixel accuracy being achieved at check points surveyed using the global positioning system (GPS). This assessment demonstrates that the outlook for DSM generation from HRSI is very promising.     

基于SPOT5卫星遥感数据的正射影像生产技术研究

结合"2010年全国土地利用变更调查监测与核查项目遥感监测任务"项目,提出SPOT5卫星遥感数据的正射影像(DOM)处理流程,重点对影像配准、影像融合、镶嵌线勾绘及影像镶嵌方法进行介绍,并用实验验证方法的可行性。实验证明,该方法具有较强的实用价值和广泛的应用前景。     

基于4D Checker的数字高程模型的质量检验方法

“4D”产品作为新型测绘产品,其质量检验是一项非常重要而又艰巨的任务。“4D Checker”是用于数字测绘产品质量检验的专业软件,适用于DEM、DOM、DLG和DRG等数字测绘产品的质量检验。主要介绍利用该软件进行数字高程模型质量检验的步骤、内容和方法。     

利用极化合成孔径雷达干涉测量技术生成DEM

极化合成孔径雷达干涉测量(PolInSAR)是目前雷达遥感的前沿领域之一,它综合了极化和雷达干涉技术(InSAR)的特点.文中应用极化干涉相干最优化技术处理了Amazon雨林地区的真实L波段PALSAR全极化数据,得到该地区的数字高程模型(DEM).与常规的单极化InSAR技术进行对比,证明了利用极化干涉技术可以显著提...     

Improving the Elevation Accuracy of Digital Elevation Models: A Comparison of Some Error Detection Procedures

The widespread availability of powerful desktop computers, easy‐to‐use software tools and geographic datasets have raised the quality problem of input data to be a crucial one. Even though accuracy has been a concern in every serious application, there are no general tools for its improvement. Some particular ones exist, however, and some results are presented here for a particular case of quantitative raster data: Digital Elevation Models (DEM). Two procedures designed to detect anomalous values (also named gross errors, outliers or blunders) in DEMs, but valid also for other quantitative raster datasets, were tested. A DEM with elevations varying from 181 to 1044 m derived from SPOT data has been used as a contaminated sample, while a manually derived DEM obtained from aerial photogrammetry was regarded as the ground truth to allow a direct performance comparison for the methods with real errors. It is assumed that a “better” value can be measured or obtained through some methodology once an outlier location is suggested. The options are different depending upon the user (DEM producers might go to the original data and make another reading, while end users might use interpolation). Both choices were considered in this experiment. Preliminary results show that for the available dataset, the accuracy might be improved to some extent with very little effort. Effort is defined here as the percentage of points suggested by the methodology in relation with its total number: thus 100 per cent effort implies that all points have been checked. The method proposed by López (1997) gave poor results, because it has been designed for errors with low spatial autocorrelation (which is not the case here). A modified version was then designed and compared with the method proposed by Felicísimo (1994). The three procedures can be applied both for error detection during DEM generation and by end users, and they might be of use for other quantitative raster data. The choice of the best methodology is different depending on the effort involved. The conclusions have been derived for a photogrammetrically obtained DEM; other production procedures might lead to different results.     

基于数字高程模型制作山区坡度分级栅格数据

山区的坡度分析可为规划建设和土地利用提供所需的地理底图,对此较为准确、有效的方法是利用高精度的数字高程模型DEM进行坡度计算及分析,数字高程模型相比于其他数据更适用于数字地形分析.本文阐述了基于1∶50 000比例尺的数字高程模型并利用ArcGIS软件进行山区坡度的计算及坡度分级栅格数据的制作,将结果与高分辨率正射影像进行叠加以初步检查结果的正确性,最后将坡度在25°以上的区域提取出来并以矢量文件形式输出.     

The Flat-Area Issue in Digital Elevation Models and Its Consequences for Rainfall-Runoff Modeling

When analyzing a digital elevation model, flat areas originating from the standard pit removal procedure can affect the characterization of flow paths and subsequent hydrologic or hydraulic analysis. In the present work, six case-study areas were selected, and two different methodologies for rainfall-runoff modeling were investigated within the framework of the Width Function Instantaneous Unit Hydrograph (WFIUH). One methodology is "standard," while the other is an "advanced" approach. The methodologies basically differ with regard to pit and flatarea treatment and flow-routing determination. In both approaches continuous rainfall-runoff modeling was applied and annual maximum hydrographs were compared. The results show that when using the "standard" approach a shorter WFIUH and a resultant hydrograph characterized by higher peak discharge and shorter duration are obtained.