Truncated geoid and gravity inversion for one point-mass anomaly   总被引：1，自引：0，他引：1  

P. Vajda  P. Vaníček 《Journal of Geodesy》1999,73(2):58-66

The truncated geoid, defined by the truncated Stokes' integral transform, an integral convolution of gravity anomalies with the Stokes' function on a spherical cap, is often used as a mathematical tool in geoid computations via Stokes' integral to overcome computational difficulties, particularly the need to integrate over the entire boundary spheroid. The objective of this paper is to demonstrate that the truncated geoid does, besides having mathematical applications, have physical interpretation, and thus may be used in gravity inversion. A very simple model of one point-mass anomaly is chosen and a method for inverting its synthetic gravity field with the use of the truncated geoid is presented. The method of inverting the synthetic field generated by one point-mass anomaly has become fundamental for the authors' inversion studies for sets of point-mass anomalies, which are published in a separate paper. More general applications are currently under investigation. Since an inversion technique for physically meaningful mass distributions based on the truncated geoid has not yet been developed, this work is not related to any of the existing gravity inversion techniques. The inversion for one point mass is based on the onset of the so-called dimple event, which occurs in the sequence of surfaces (or profiles) of the first derivative of the truncated geoid with respect to the truncation parameter (radius of the integration cap), its only free parameter. Computing the truncated geoid at various values of the truncation parameter may be understood as spatial filtering of surface gravity data, a type of weighted spherical windowing method. Studying the change of the truncated geoid represented by its first derivative may be understood as a data enhancement method. The instant of the dimple onset is practically independent of the mass of the point anomaly and linearly dependent on its depth. Received: 26 September 1996 /Accepted: 28 September 1998  相似文献   

彩色扫描地图点状符号的自动识别     

骆剑承  周成虎  赵千钧  万庆 《地球信息科学学报》1999,1(2):57-62

本文初步探讨了彩色扫描地图上点状符号自动识别的方法及软件设计的模型和框架.彩色扫描地图上规则符号的主要视觉特征是颜色、形状及大小.识别符号建立在符号模式库的基础上,根据模式库中提供的颜色类型,通过颜色分层方法去寻找彩色扫描地图上的目标,然后提取其轮廓线,获取形状和大小等特征量,最后用符号特征相量与模式库中的特征相量相匹配,对符号进行判别分类,并通过坐标转换,输出符号的中心点地理坐标及符号的其他对应属性.本文最后以彩色地图上电信号强度符号的识别为实例,论述了具体应用系统的设计和开发.  相似文献   

Fractal characterization of the spatial distribution of geological point processes   总被引：1，自引：0，他引：1  

Renguang Zuo  Frederik P. Agterberg  Qiuming Cheng  Lingqing Yao 《International Journal of Applied Earth Observation and Geoinformation》2009

Geological point processes can be used to model point patterns occurring frequently in a wide variety of geoscience fields, including the study of mineral deposits, oil producing wells, earthquakes, and landslides. Characterization of the spatial distribution of GPP has implications for understanding the properties of the underlying geological processes and events. Three examples of GPP dealing with (1) metallic mineral deposits, (2) oil producing wells, and (3) aftershocks of the Wenchuan earthquake (on 12 May 2008, magnitude 8.0) are presented to illustrate that (1) the spatial distribution of geological point processes generally shows clustering implying rejection of the Poisson model because L(r) > L_Pois(r); (2) the clustering statistics of the underlying geological processes are fractal; and (3) the size distribution of geological point processes is scale invariant. These results indicate existence of a fundamental law concerning the fractal nature of the point distributions generated by geological point processes.  相似文献   

三维激光扫描测量天幕钢结构精度分析     

范占永  袁铭  严勇  叶宝  葛坤龙 《现代测绘》2009,32(2)

本文通过使用三维激光扫描仪对天幕钢结构的立柱、横梁与行架进行扫描测量,建立点云模型,获取钢柱中心坐标,并与全站仪测量的结果进行比较,以确定三维激光扫描在工程上能够达到的测量精度,为三维激光扫描仪在钢结构工程竣工验收上的运用做准备.  相似文献   

高铁地震震源子波时间函数及验证          下载免费PDF全文

张固澜  何承杰  李勇  段景  王婷一  詹熠宗  杜皓  罗帆 《地球物理学报》2019,62(6):2344-2354

基于纵横波产生机理并结合高铁列车及铁轨结构,本文给出了高铁列车产生地震纵波及横波震源(点源及等效源)子波的时间函数;通过实际高铁地震数据及合成高铁地震数据分析,验证了高铁地震震源子波时间函数的合理性;在高铁列车匀速、加速及减速运行情况下,利用高铁地震点源子波合成记录分析了高铁地震震源子波的频谱特征,为实际高铁地震数据处理解释奠定了良好的基础.  相似文献   

Target-oriented imaging using extended image volumes: a low-rank factorization approach     

Rajiv Kumar  Marie Graff  Ivan Vasconcelos  Felix J. Herrmann 《Geophysical Prospecting》2019,67(5):1312-1328

Imaging in geological challenging environments has led to new developments, including the idea of generating reflection responses by means of interferometric redatuming at a given target datum in the subsurface, when the target datum lies beneath a complex overburden. One way to perform this redatuming is via conventional model-based wave-equation techniques. But those techniques can be computationally expensive for large-scale seismic problems since the number of wave-equation solves is equal to two times the number of sources involved during seismic data acquisition. Also conventional shot-profile techniques require lots of memory to save full subsurface extended image volumes. Therefore, we can only form subsurface image volumes in either horizontal or vertical directions. To exploit the information hidden in full subsurface extended image volumes, we now present a randomized singular value decomposition-based approach built upon the matrix probing scheme, which takes advantage of the algebraic structure of the extended imaging system. This low-rank representation enables us to overcome both the computational cost associated with the number of wave-equation solutions and memory usage due to explicit storage of full subsurface extended image volumes employed by conventional migration methods. Experimental results on complex geological models demonstrate the efficacy of the proposed methodology and allow practical reflection-based extended imaging for large-scale five-dimensional seismic data.  相似文献   

Long-term coastal erosion assessment along the coast of Karnataka,west coast of India     

K.Sowmya  M.Dhivya Sri  Aparna S.Bhaskar  K.S.Jayappa 《国际泥沙研究》2019,34(4):335-344

Coastal areas are always under frequent threat from various natural processes and man-induced activities. Coastal erosion is recognized as the permanent loss of land along the shoreline resulting in the transformation of the coast. The current study focuses on long-term coastal erosion analysis of the entire Karnataka coast using Remote Sensing, Geographical Information System (GIS), Linear Regression Rate (LRR), and End Point Rate (EPR) techniques. Analysis of 26 (1990 to 2016) years of erosion using Landsat images by the use of the Digital Shoreline Analysis System (DSAS) tool has been done. The results show a high erosion rate at Ullal during this period (LRR -1.3m/yr) and accretion at Devbagh (LRR 3.2 m/yr). The southern Karnataka coast faces severe erosion especially at Ullal, where the settlement is high. At Thanirbhavi, Mukka, Kota, and Om Beaches erosion also is noticed. Both anthropogenic activities like ports, seawalls, breakwaters, etc. and natural processes like long shore drift, seasonal variation, etc. are factors affecting the shoreline change along the Karnataka coast.  相似文献   

三维激光扫描技术获取高精度DTM的应用研究   总被引：1，自引：0，他引：1  

董秀军 《工程地质学报》2007,15(3):428-432

三维激光扫描技术又被称为实景复制技术,是测绘领域继GPS技术之后的又一次技术革命,它突破了传统的单点测量方法,具有高效率、高精度的独特优势。三维激光扫描技术能够提供扫描物体表面的三维点云数据,因此可以用于获取高精度高分辨率的数字地形模型。本文将以一工程边坡为例讨论利用三维激光扫描技术快速获取数字地形模型的方法,着重论述三维点云数据的获取、拼接、坐标校正、去噪及数字高程模型的生成方法,由此得出在一定空间范围内利用三维激光扫描技术快速获取高精度高分辨率的数字地形模型具有可行性。  相似文献   

南极长城站北斗基准站建设、运行及稳定性分析     

吴文会  朱李忠  王丽欣 《测绘与空间地理信息》2019,42(5):78-80

介绍了长城站北斗基准站建设和运行的基本情况,并对其稳定性进行了分析。从结果可以看出,基准站观测环境和数据质量良好,站址稳定,常年连续运行和数据实时回传正常。通过设备不断维护升级可以满足北斗全球卫星导航系统建成后的跟踪观测需求,进一步优化和拓展了南极大陆的北斗卫星跟踪监测网络。  相似文献   

基于高分遥感影像和POI的国土空间规划现状细化调查     

王艳阳  梁宇哲  罗伟玲  谢贻新  刘济坤 《热带地理》2020,40(4):649-658

当前国土空间规划现状细化调查尚处于外业核查与内业人工目视判读的方法探索阶段,缺乏较高效率、较高精准度的技术方法。因此,文章提出一种融合高分遥感影像图像信息和POI类别属性信息的数据特点,利用核密度分析和面向对象的信息提取方法,实现对国土空间规划现状地类的细化调查。通过对城镇中心和城镇边缘2个研究区进行建筑物提取和POI属性挂接,识别出各建筑物的使用功能类别,再与2019年第三次全国国土调查的国土利用现状图层进行空间叠加,完成对研究区的地类细化调查。结果表明,经样本误差矩阵评价建筑物提取结果具有较高分类精度,研究区的地类细化调查结果准确度达到86.2%,且大大提高了工作效率,为国土空间规划现状调查逐步走向精准化、高效化和智能化道路提供了方法和思路借鉴,具有重要的深入研究和应用推广意义。  相似文献