Local accuracy measures for digital terrain models   总被引：1，自引：0，他引：1  

Karl  Kraus  Wilfried  Karel  Christian  Briese  Gottfried  Mandlburger 《The Photogrammetric Record》2006,21(116):342-354

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城市地质信息系统及其应用     

金江军  潘懋  赖志斌  吕广宪  王占刚 《国土资源信息化》2006,(4):16-20

本文提出了城市地质信息系统的总体结构,系统划分为数据层、应用层和服务层三个层次。由信息数据录入与管理子系统、三维地质体建模子系统、数据共享与社会化服务子系统构成。然后分数据库和业务应用系统两个部分阐述了系统的开发方案,并说明了高精度三维地质模型快速构建、大数据量模型运行和多元数据一体化显示这三个关键技术的解决方案。  相似文献   

基于激光点云的3维可视化方法     

周克勤  赵煦  丁延辉 《测绘学院学报》2006,(1)

介绍了利用3维激光点云与数字影像,生成云冈石窟正射影像的原理与方法。采用激光扫描与数码相机同步获取石窟、石佛的3维点云与数字影像,建立点云与数字影像映射关系模型,将影像的纹理信息赋予3维点云模型,实现点云模型真彩色3维可视化,并在此基础上生成正射影像图。研究成果对于历史遗迹、文物保护与修复具有重要意义。  相似文献   

筛法/激光粒度仪法接序测定全样泥沙级配的调整处理     

牛占  李静  和瑞莉  吉俊峰 《水文》2006,26(1):72-75

筛法／激光粒度仪法接序测定全样泥沙粒度是泥沙粒度分析的基本方法,分级交混现象会时有出现,需要研究全样级配的调整处理。本文从先用筛分法分析全样泥沙到分界粒级,再将分界粒级以下(筛下)泥沙做全样用激光粒度分析仪法分析的作业程序,按激光粒度分析仪法小于分界粒级D_(FJ)的泥沙的质量／体积比例等于1(100％)和小于1(100％)两种可能,提出了相应的粒度分析级配序列计算调整方法和全样级配序列的接序方法。分析了以“筛法分界粒级级配为准”和“以激光粒度分析仪法最大粒级级配为准”的不足。认为激光粒度分析仪法向上粒级的分界交混质量较小,应用本文“激光粒度分析仪法分析小于分界粒级D_(FJ)的泥沙的质量／体积比例小于1(100％)”的方法和公式,调整处理分级交混问题比较合理。  相似文献   

Spatio-temporal estimation of shallow landslide hazard triggered by rainfall using a three-dimensional model     

Cheng Qiu  Tetsuro Esaki  Mowen Xie  Yasuhiro Mitani  Chunxiang Wang 《Environmental Geology》2007,52(8):1569-1579

A shallow landslide triggered by rainfall can be forecast in real-time by modeling the relationship between rainfall infiltration and decrease of slope stability. This paper describes a promising approach that combines an improved three-dimensional slope stability model with an approximate method based on the Green and Ampt model, to estimate the time–space distribution of shallow landslide hazards. Once a forecast of rainfall intensity and slope stability-related data, e.g., terrain and geology data, are acquired, this approach is shown to have the ability to estimate the variation of slope stability of a wide natural area during rainfall and to identify the location of potential failure surfaces. The effectiveness of the estimation procedures described has been tested by comparison with a one-dimensional method and by application to a landslide-prone area in Japan.  相似文献   

Li2B4O7熔融玻璃-激光剥蚀等离子体质谱法测定水系沉积物国家标准定值样品中微量元素     

姜劲锋  徐鸿志郭伟柳小明  胡圣虹 《岩矿测试》2007,26(3):171-175

建立了激光剥蚀等离子体质谱法直接测定Li2B4O7熔融玻璃中微量元素的分析方法。详细讨论了内标元素的选择及Li2B4O7熔融玻璃的均一性、背景空白对分析测定的影响。以Li2B4O7熔融玻璃中低同位素丰度的6Li作内标，水系沉积物国家标准参考物质熔融玻璃建立多元素标准校正曲线，用于标准参考物质及水系沉积物定值样品的分析，测定值与标准值或溶液雾化等离子体质谱结果比较，具有较好的一致性。  相似文献   

低温加热后伊利石的激光拉曼光谱特征     

王强周瑶琪  马在平陈勇颜世永  刘超英张娟 《岩矿测试》2007,26(3):188-192

在分析伊利石结构和常温下拉曼光谱特征的基础上，尝试用激光拉曼光谱法监测伊利石随温度变化而发生的一系列情况，对经历了不同温度后的伊利石样品开展了拉曼光谱研究。结果显示，高波数段羟基振动峰带宽随温度升高呈现逐渐缩短的趋势，且其振动峰峰面积比值随温度升高而逐渐增大，并最终利用这些特征建立了温度与拉曼峰特征参数的数学表达式。  相似文献   

Towards a protocol for laser scanning in fluvial geomorphology     

George Heritage  David Hetherington 《地球表面变化过程与地形》2007,32(1):66-74

Advances in spatial analytical software allow digital elevation models (DEMs) to be produced which accurately represent landform surface variability and offer an important opportunity to measure and monitor morphological change and sediment transfer across a variety of spatial scales. Many of the techniques presently employed (aerial LIDAR, EDM theodolites, GPS, photogrammetry) suffer coverage or resolution limitations resulting in a trade‐off between spatial coverage and morphologic detail captured. This issue is particularly important when rates of spatial and temporal change are considered for fluvial systems. This paper describes the field and processing techniques required for oblique laser scanning to acquire 0·01 m resolution digital elevation data of an upland reach of the River Wharfe in the UK. The study site is variable with rapidly changing morphology, diverse vegetation and the presence of water, and these are evaluated with respect to laser data accuracy. Scan location, frequency and distance are discussed with reference to survey accuracy and efficiency, and a field protocol is proposed. Scan data cloud merging was achieved with a high degree of precision (sub‐centimetre) and positional data are shown to be very accurate for exposed surfaces. Vegetation and water decrease the accuracy, as the laser pulse is often prevented from reaching the ground surface or is not returned. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Absolute Tilt from a Laser Guide Star: A First Experiment     

S. Esposito  R. Ragazzoni  A. Riccardi  C. O'Sullivan  N. Ageorges  M. Redfern  R. Davies 《Experimental Astronomy》2000,10(1):135-145

Absolute tip–tilt recovery using a tilt signal measured on a Laser Guide Star is a central problem in the framework of the development of Adaptive Optics Systems reaching full sky coverage down to visible wavelengths. In the past few years, various techniques aimed at solving this problemhave been proposed. However only a couple of these has been recentlytested in practice.We report about an experiment aimed at evaluating the performance of one of these techniques called the Elongation Perspective technique. Our experiment has been performed using the ALFA system inCalar-Alto (Spain) and involves the simultaneous operation of the 3.6 m and the 2.2 m telescopes at the Observatory.This article describes the telescope configuration used, as well as the datareduction process carried out in order to estimate the scientific objecttilt. The technique performances are discussed in terms of the residualtilt error variance and related correlation coefficient. The analysisshows that, despite the low SNR of our measurements, the atmospheric tiltvariance is reduced to 80% of its initial value corresponding to acorrelation coefficient of about 0.6. To get a betterestimate of the performance achievable using this technique,the tilt error variance due to photon noise in the laser measurementis estimated and removed from the obtained tilt error variance.When this correction is done, thisvariance is reduced to about 50% of its initial value, showingthat the use of this technique can give rise to a significant reduction of the scientific object image motion.  相似文献   

Laser ablation ICP—MS — a new dating tool in Earth science     

Jan Košler 《Proceedings of the Geologists' Association. Geologists' Association》2007,118(1):19-24

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