Research on the Monitoring the Ground Subsidence of Xi＇ an Based on InSAR-GIS Technique

针对合成孔径雷达干涉测量（InSAR）技术在监测地表形变的数据后处理及成果表达和分析方面存在的一些局限性问题,研究通过GIS数据库管理InSAR监测数据和相关区域的地理、水准及GPS数据等辅助数据,以及利用GIS空间分析功能埘监测结果进行分析的方法与实现。以西安地区InSAR数据为研究对象对提出的方法进行实现,试验结果表明,GIS技术与InSAR技术卡“结合用于地面沉降监测可以有效地解决在监测地表形变的数据后处理及成果表达和分析方面的局限性问题。     

A digital geometry on the tetrakis square tiling—Distance and coarsening

There are various tessellations of the plane, including three regular and eight semi-regular tilings. The square grid is self-dual, and the hexagonal and triangular tilings are dual to each other. The semi-regular tessellations are based on more than one type of regular tiles, while their dual tilings are based on a sole but not a regular tile. In various applications, including Geographical Information Systems, it is worth considering non-regular grids instead of the most used square grid. In this article, we are interested in the dual of the semi-regular truncated quadrille tiling, T(8,8,4), which is also known as the Khalimsky grid due to its connectedness structure. In our grid, which is called the tetrakis square or kisquadrille tiling, while it is denoted by D(8,8,4), we consider the right-angled triangle regions of the usual two-dimensional Khalimsky graph as tiles/pixels. We give an easy-to-use coordinate frame addressing the triangles of all the four different orientations. Neighbor relations are described mathematically based on this frame. Based on the shortest path algorithm, a closed formula is proven to compute the digital, that is, path-based distance on this grid. Some properties of the distance function have also been studied. Hierarchical coarsening is a frequently used technique both in Geometric and Geographical Information Systems to rescale some parts of the map. The tetrakis square grid is apt for hierarchical coarsening, and thus, it can easily be used in image compression and multigrid and other related methods.     

Airborne laser scanning—an introduction and overview

This tutorial paper gives an introduction and overview of various topics related to airborne laser scanning (ALS) as used to measure range to and reflectance of objects on the earth surface. After a short introduction, the basic principles of laser, the two main classes, i.e., pulse and continuous-wave lasers, and relations with respect to time-of-flight, range, resolution, and precision are presented. The main laser components and the role of the laser wavelength, including eye safety considerations, are explained. Different scanning mechanisms and the integration of laser with GPS and INS for position and orientation determination are presented. The data processing chain for producing digital terrain and surface models is outlined. Finally, a short overview of applications is given.     

Distribution of Large Volume Image Data Using the Mixed Mode of Java Servlet and COM on Web

This paper reports some researches on distribution of large volume image data using techniques of the Mixed Mode of Java Servlet and COM on Web. The architecture and key technologies are discussed in detail. The web distribution system of image is implemented and the system is tested by the application instances. At last, the advantages and disadvantages for this web image distribution mode are analyzed.     

Combination of GPS and VLBI on the observation level during CONT11—common parameters,ties and inter-technique biases

Multi-technique space geodetic analysis software has been developed which allows to combine data on the observation level. In addition to local tie information, site-wise common parameters, i.e., troposphere and clocks, can be estimated with this software. Thus, it will be discussed how common parameters have to be estimated and where biases/offsets need to be taken into account. To test such a novel concept, Global Positioning System (GPS) and Very Long Baseline Interferometry (VLBI) data from the CONT11 campaign are being utilized. Since the VLBI baselines of this campaign extend over several thousands of kilometers, GPS data are processed in precise-point positioning mode and satellite orbits and clocks are kept fixed to the IGS final products. From the obtained results, it can be shown that the combination of space geodetic data on the observation level leads to a consistent improvement of station position repeatability as well as nuisance parameters like troposphere estimates. Furthermore, estimation of common parameters (troposphere or clocks) at co-located sites helps to improve the solution further and derive an utmost physically consistent model of the concerned parameters.     

Spectral Representation and Analysis of the KBR Precision Based on the Earth Gravity Spectrum

IntroductionThe GRACE (gravity recovery and cli mate ex-peri ment) mission,twin satellites flying in for-mation ,which carries several key payloadsinclu-ding KBR (K-band ranging) system, waslaunchedin 2002 . The unique design of GRACEmissionis expected to lead to ani mprovement inseveral orders of magnitude in these gravitymeasurements and allow much i mproved resolu-tion of the Earth gravity field of finer scale overbothland and ocean to study a lot of geosciencesphenomena[1]. Though th…     

Spectral Representation Precision Based on the and Analysis of the KBR Earth Gravity Spectrum

Satellite-to-Satellite Tracking in low-low model （SST-Ⅱ） is a new technique to resolve the series of problems met in the determination of the earth＇s gravity field. As the key technique of SST-Ⅱ, KBR can get SST-Ⅱ measurements directly. So the KBR performance analysis is the first step in SST-Ⅱ design. In this paper, assuming that the satellite pairs of SST-Ⅱ are in near circle polar orbits, the spectrum relationship between the earth gravity field and KBR is established using analytic method. And then some examples are analyzed, the suggestions and conclusions are drawn from these examples. The research results could be taken as a reference for future satellite gravity project of China.     

A GIS-based glacier inventory for the Antarctic Peninsula and the South Shetland Islands —A first case study on King George Island

The aim of the international project “Global Land Ice Measurements from Space (GLIMS)” headed by the US Geological Survey is to establish a world wide glacier inventory based on satellite imagery. This data set will form a first digital baseline study for future glacier monitoring. The presented GIS-based glacier inventory for King George Island is a case study for the area of the Antarctic Peninsula. In the database of the glacier inventory topographic information, specific glaciological parameters as well as metadata will be included. The topographic data consists of drainage basin limits, basin areas, altitudinal ranges, perimeters and mean lengths. Glaciological data sets should comprise information on glacier retreat in different periods, glacier velocities, ice thickness and bedrock topography as well as derived parameters. Modelled and measured mass balance parameters could be included as additional data layers. In particular, these metadata records must comprise background information on data accuracy and data sources and should be compatible with a future data model for the King George Island GIS (KGIS). Three examples illustrate that the GLIMS database will not only contain information valuable for glaciological applications, but also other environmental studies on the island will benefit from this standardised remote sensing data sets. Therefore, a very close link between the data models of KGIS and GLIMS has to be established to enable these synergisms. Finally, better access to historic aerial photography would enable a continuous record of glacier retreat from the beginning of the 1950's onward.     

Constructive approximation and numerical methods in geodetic research today – an attempt at a categorization based on an uncertainty principle

Current activities and recent progress on constructive approximation and numerical analysis in physical geodesy are reported upon. Two major topics of interest are focused upon, namely trial systems for purposes of global and local approximation and methods for adequate geodetic application. A fundamental tool is an uncertainty principle, which gives appropriate bounds for the quantification of space and momentum localization of trial functions. The essential outcome is a better understanding of constructive approximation in terms of radial basis functions such as splines and wavelets. Received: 4 May 1999 / Accepted: 21 May 1999     

Utilizing the Potential of World View −2 for Discriminating Urban and Vegetation Features Using Object Based Classification Techniques

With the availability of very high resolution multispectral imagery, it is possible to identify small features in urban environment. Because of the multiscale feature and diverse composition of land cover types found within the urban environment, the production of accurate urban land cover maps from high resolution satellite imagery is a difficult task. This paper demonstrates the potential of 8 bands capability of World View 2 satellite for better automated feature extraction and discrimination studies. Multiresolution segmentation and object based classification techniques were then applied for discrimination of urban and vegetation features in a part of Dehradun, Uttarakhand, India. The study demonstrates that scale, colour, shape, compactness and smoothness have a significant influence on the quality of image objects achieved, which in turn governs the classified result. The object oriented analysis is a valid approach for analyzing high spatial and spectral resolution images. World View 2 imagery with its rich spatial and spectral information content has very high potential for discrimination of the less varied varieties of vegetation.     

On non-linear low–low SST observation equations for the determination of the geopotential based on an analytical solution

In satellite data analysis, one big advantage of analytical orbit integration, which cannot be overestimated, is missed in the numerical integration approach: spectral analysis or the lumped coefficient concept may be used not only to design efficient algorithms but overall for much better insight into the force-field determination problem. The lumped coefficient concept, considered from a practical point of view, consists of the separation of the observation equation matrix A=BT into the product of two matrices. The matrix T is a very sparse matrix separating into small block-diagonal matrices connecting the harmonic coefficients with the lumped coefficients. The lumped coefficients are nothing other than the amplitudes of trigonometric functions depending on three angular orbital variables; therefore, the matrix N=B ^T B will become for a sufficient length of a data set a diagonal dominant matrix, in the case of an unlimited data string length a strictly diagonal one. Using an analytical solution of high order, the non-linear observation equations for low–low SST range data can be transformed into a form to allow the application of the lumped concept. They are presented here for a second-order solution together with an outline of how to proceed with data analysis in the spectral domain in such a case. The dynamic model presented here provides not only a practical algorithm for the parameter determination but also a simple method for an investigation of some fundamental questions, such as the determination of the range of the subset of geopotential coefficients which can be properly determined by means of SST techniques or the definition of an optimal orbital configuration for particular SST missions. Numerical results have already been obtained and will be published elsewhere. Received: 15 January 1999 / Accepted: 30 November 1999     

Geospatial Information Service Based on Digital Measurable Image——Take Image City·Wuhan as an Example

LBS (location-based service) is a remarkable outcome of the development from GIS to geospatial information service. Faced by the requirements of geospatial information from the masses and the opportunity provided by the next generation Internet and Web 2.0, a new model of geospatial information service based on DMI (digital measurable image) is presented. First, the concept of LBS and the opportunities of Web 2.0 are introduced, then the characteristic of DMI is discussed. Taking the Image City·Wuhan as an ...     

Landuse/land cover change in Mumbai-Navi Mumbai cities and its effects on the drainage basins and channels — A study using GIS

The Mumbai-Navi Mumbai cities (Bombay and New Bombay) are among the highest populated cities in the country. The population pressure has caused drastic landuse change in the last seventy years. Multi-date data from SOI topographical maps and Landsat TM digital data have been used to study the landuse change. The change has been quantified using A GIS It was observed that 55% reduction in forest/agricultural land, while a 300% increase in built-up land has taken place in the last seventy years. This has affected the natural drainage system of the cities, causing flooding during monsoons. The quantum of draînage basin area and stream length, in the ten basins which drain the area, under influence of built-up land was found by using a map overlay of the drainage network map and landuse map of 1994. The results shed light on the extent of drainage network disruption within these two neighbouring cities.     

German Maps and Survey on the Western Front, 1914–1918

Abstract

Fighting the 1914–18 war largely on enemy territory in both the east and the west, German was at a disadvantage compared to the Allies when it came to survey and mapping as it did have access to much of the geodetic, topographic and cartographic data, relating to this terrain, necessary for modern warfare — in particular for artillery survey. German and Austria did, however, have a commanding lead in terrestrial and aerial photogrammetry, and the latter was to prove crucial in the production of accurate large-scale maps of enemy and occupied territory. Despite strong forces of conservatism in the high and field commands and in the artillery and military survey organizations, new air survey methods based on the photogoniometer and radial triangulation were rapidly developed. Through continual laboratory and field experimentation and testing, German was to increase her lead in aerial photogrammetry, and by the end of the war had not only set up a completely new air survey organization but was developing a new generation of optical-mechanical stereoplotting instruments of great precision. German progress was not, however, evident in all fields of military survey, and this paper examines the approaches taken by German to survey and mapping on the Western Front, and briefly compares and contrasts them with those of the Allies.     

Reservoir Impact Assessment on Land Use/Land Cover and Infrastructure—A Case Study on Polavaram Project

The present study aims to estimate the loss of land use/cover and infrastructure facilities due the submergence by constructing the reservoir over the River Godavari at Polavaram Village. Detailed Land use/cover mapping has been carried out using LISS-III sensor data of IRS P6 satellite and linked to socio-economic data to analyze the administrative boundary wise environmental impact assessment in the study area. Land use/cover features are estimated from the Remote Sensing data through visual interpretation. Area covered below the 45.72 m contour above the mean sea level (MSL) is taken as submerged area due to the dam construction. Total area under submergence is estimated to be 58,658 ha, where 159 villages of three districts are affected by the project. The total population to be rehabilitated is about 1.2 lakhs, out of which maximum affected are Scheduled Tribes (58,781). Besides this, about 311 educational institutions, 202 medical institutions, 37 credit institutions and 55 postal institutions will be submerged due to the project. Further, nine mining sites, 24 tourist/historical sites and 78 agro-based industries will be displaced. The total road length of 673 km will go under submergence.     

Monitoring of River Center Line and Width—A Study on River Brahmaputra

Monitoring of river width and centerline is one of the most important activities in river engineering. Changes in the width and center line can be attributed to several reasons and monitoring these changes can be conveniently achieved with the aid of remote sensing images. In this study, digital image processing techniques have been implemented using the image processing tool-box available in MATLAB for studying temporal variations of width and centerline of the river Brahmaputra in its 300 Km reach in the state of Assam, India. The current study uses relatively high resolution imageries acquired from the LANDSAT series of satellites. Apart from the LANDSAT imageries, the low resolution imageries acquired by MODIS program is also used in order to see the variation in the obtained results. The evaluation of the results shows that the digital image processing technique is very handy and can be applied to obtain the centerline and width of a river. The evaluation also shows that the low resolution image can also be used for obtaining centerline of a river. However, it may give erroneous result when width of the river is narrow or very large.     

Report on the ISPRS Journal of Photogrammetry and Remote Sensing (PRS) for the period 1996–2000

This report was presented by the author, as Editor-in-Chief (EIC) of PRS, to the General Assembly of the Delegates of the ISPRS Members during the 19th ISPRS Congress, Amsterdam, 16–23 July 2000. Since it summarises in quite some detail many new developments since the last Congress that are of interest not only to ISPRS in general, but also to authors and readers, a slightly modified version of this report is published here.     

A Fitting Algorithm of the Apparent Moon Center and Its＇ Application on Fast Orientation

基于电子经纬仪对月球明亮区域边沿的观测采样,提出一种月球视圆面中心拟合算法,推导出详细的计算公式。通过实际观测试验验证该算法的可靠性,较好地解决了月面中心的确定问题。在此基础上,探索一种测月快速定向方法。运用此方法进行天文定向,内符合精度和外符合精度均优于±2．0”。测月定向可有效弥补传统天文定向夜间只能依靠观测恒星进行的不足,扩展天文测量的使用范围。由于太阳的视面也是正圆,测月定向方法同样适用于测日定向。     

Seminar on the Wang Zhizhuo''''s Aeademie Thinking and Digital Photogrammetry will be Held in Wuhan

Seminar on the Wang Zhizhuo's academic thinking and digital photogrammetry organized by the Wuhan Technical University of Surveying and Mapping(WTUSM)and Commission of Photogrammetry and Remote Sensing, Chinese Society of Surveying and Mapping(CSSM)and will be held in Wuhan, Dec. 11—17, 1988, just on the 80th     

Remote sensing data from IRS satellites — past, present and the future

Under Indian Remote Sensing Satellite Programme, so far seven satellites have been launched to provide land, water, agricultural and Oceanographic information for resources monitoring and management under National Natural Resources Management System. The continuity of the data services is planned by way of providing improved multi-spectral data, panchromatic data, and oceanographic/atmospheric data, in the future also. The various errors in the satellite data namely radiometric and geometric errors which are to be corrected on ground before the data is put for use have been explained. The characteristics of the future satellites are also described in this article.