共同的责任共同的行动

国土资源部“保增长、保红线”行动电视电话会议召开后，福建省委省政府高度重视，积极研究措施，投入“双保”行动。省长黄小晶强调：“双保行动”是学习贯彻科学发展观的要求，要保持经济持续较快增长，又要保红线，这是客观要求，必须做到，只要用心，完全可以做到。在当前扩大内需保障发展的特殊形势面前，国土资源部积极主动、科学应对，保增长保红线双帜并举，具有十分重要意义。     

基于MapX的电子地图的制作

随着地理信息系统(GIS)的发展与完善,它的设计开发工具也日臻成熟,MapInfo公司顺应这一发展潮流,开发了一种地图控件——MapX,能实现MapInfo的绝大部分功能。主要论述了MapX的特征,以及用相关的计算机语言和多媒体技术提供一种高效的、脱离一般平台的电子地图的制作方法,并介绍了所制作的电子地图的内容及特点。     

薪火相传的伟业:塞维利亚的伊西多尔

<正>公元5世纪,随着西罗马帝国的灭亡,西欧进入了"黑暗时期",在战火不绝的动荡岁月中,残存下来的古代文化知识     

GIS的应用与发展的探讨

从网络GIS应用、移动GIS应用、虚拟GIS应用、GIS与RS集成的应用、GIS与GPS集成的应用等5个方面论述了当前GIS的应用,并对当前GIS软件的发展方向提出了一些看法     

基于NewMap的教育地理信息系统的开发

以教育地理信息系统的设计和开发为例,全面阐述了系统设计的原则、总体结构,以及数据组织和功能实现过程。该系统基于NewMap开发,调用地理信息公共服务平台数据为教育资源的公众服务提供了新的途径,又很好地起到了数字城市建设中的示范应用作用。     

基于LabVIEW的GPS激光测距动态定位系统的数据采集平台的开发

介绍了GPS激光测距动态定位系统的功能及组成数据采集平台的各个软件模块，采用LabVIEW集成开发环境下设计的GPS激光测距动态定位系统的数据采集平台，实现了对GPS定位信息、激光测距信息和数字罗盘角度信息的采集、存储及实时显示。     

基于MATALAB的GPS仿真的研究

针对在GPS系统开发过程中出现的高复杂度、投资大、风险性高的问题,通过建立GPS数学仿真模型,且选用MATLAB来进行GPS仿真。理论分析和实验表明,利用仿真技术不仅能优化系统设计、节省经费且能够提高工作效率。     

基于AutoCAD的无属性的高程图形数据的处理

在传统的测绘方式中,由于受成图方式和制图软件的限制,一些数字化成果的高程数据没有属性,给数据处理和利用造成了一定的麻烦。介绍了通过利用计算机程序解决这一问题,在实际应用中效果较好。     

Geoid deformation and elevation influence caused by building loading

The paper studies the ground vertical deformation and the geoid undulation caused by loading of neighboring buildings, based on the loading tides theory. The influence on elevation is also considered. The results show that the ground vertical deformation and the geoid undulation both reach millimeter magnitude. Therefore, it is obvious that the building loading significantly affects the precise engineering surveying, and it must be seriously considered in application.     

利用CORS站网监测三峡地区环境负荷引起的地壳形变与重力场时空变化

受地球动力学因素特别是地球表层大气、地表水及地下水动力环境影响,地面站点位置、地球重力场及大地水准面随时间变化。以三峡地区CORS站网为主,少量重力台站为辅,采用负荷形变与地球重力场严密组合方法,综合确定了2011-01-2015-06三峡地区环境负荷驱动的地壳形变与重力场月变化,结果显示:（1）CORS站网具备地壳垂直形变、大地水准面及地面重力变化的监测能力;（2）三峡地区地壳垂直形变年变化幅度36.1 mm,大地水准面年变化幅度28.2 mm,地面重力年变化幅度117.4 μGal;（3）CORS站网地面重力变化监测精度水平不低于流动重力场重复测量;（4）CORS站网地壳垂直形变与地面重力变化监测具有一定的外推预报能力。     

海洋重力大地水准面的确定

美国海洋卫星测高仪的出现,使应用Hotine积分确定海洋大地水准面成为现实。本文通过对Hotine积分及垂线偏差的计算公式进行改进,较好地改善了求和项的收敛性,减小了截断误差影响,并提出了利用Hotine函数和重力异常确定海洋大地水准面的方法。 实际计算表明:海洋重力大地水准面的精度在1米以内;卫星测高大地水准面间存在0.5米系统差;它和海底地形有一定的相关性,能较好地反映出海底地形的宏观特性。     

The Bruns formula in three dimensions

The Bruns formula is generalized to three dimensions with the derivation of equations expressing the height anomaly vector or the geoid undulation vector as a function of the disturbing gravity potential and its spatial derivatives. It is shown that the usual scalar Bruns formula provides not the separation along the normal to the reference ellipsoid but the component of the relevant spatial separation along the local direction of normal gravity. The above results which hold for any type of normal potential are specialized for the usual Somigliana-Pizzetti normal field so that the components of the geoid undulation vector are expressed as functions of the parameters of the reference ellipsoid, the disturbing potential and its spatial derivatives with respect to three types of curvilinear coordinates, ellipsoidal, geodetic and spherical. Finally the components of the geoid undulation vector are related to the deflections of the vertical in a spherical approximation.     

Separation between reference surfaces of selected vertical datums

This paper discusses the separation between the reference surface of several vertical datums and the geoid. The data used includes a set of Doppler positioned stations, transformation parameters to convert the Doppler positions to ITRF90, and a potential coefficient model composed of the JGM-2 (NASA model) from degree 2 to 70 plus the OSU91A model from degree 71 to 360. The basic method of analysis is the comparison of a geometric geoid undulation derived from an ellipsoidal height and an orthometric height with the undulation computed from the potential coefficient model The mean difference can imply a bias of the datum reference surface with respect to the geoid. Vertical datums in the following countries were considered: England, Germany, United States, and Australia. The following numbers represent the bias values of each datum after adopting an equatorial radius of 6378136.3m: England (-87 cm), Germany (4 cm), United States (NGVD29 (-26 cm)), NAVD88 (-72 cm), Australia AHD (mainland, -68 cm); AHD (Tasmania, -98 cm). A negative sign indicates the datum reference surface is below the geoid. The 91 cm difference between the datums in England and Germany has been independently estimated as 80 cm. The 30 cm difference between AHD (mainland) and AHD (Tasmania) has been independently estimated as 40 cm. These bias values have been estimated from data where the geometric/ gravimetric geoid undulation difference standard deviation, at one station, is typically ±100 cm, although the mean difference is determined more accurately.The results of this paper can be improved and expanded with more accurate geocentric station positions, more accurate and consistent heights with respect to the local vertical datum, and a more accurate gravity field for the Earth. The ideas developed here provide insight on the determination of a world height system.     

海洋重力似大地水准面与区域测高似大地水准面的拟合问题

研究了将陆地重力似大地水准面与GPS水；住似大地水准面拟合的处理方法推广到海洋的问题．首先从理论上证明了当存在海面地形．则海洋大地水准面与似大地水准面不重合．导出了在海洋上大地水；住面差距与高程异常之间差值的公式．由此给出了求定平均海面相对于区域高程基准的正常高以及测高似大地水准面的计算公式。由于测高平均海面与GPS大地高有相近的精度．提出了将海洋重力似大地水准面与区域测高似大地水准面拟合的处理方法．并利用当前最新的海面地形模型和测高平均海面模型做了数值估计。     

三峡水库蓄水对地壳形变及大地水准面的影响

利用资源三号(ZY-3)高分辨率遥感影像提取三峡库区水体数据,通过负荷格林函数积分模型法计算出三峡水库蓄水过程中水体对地壳形变及对大地水准面的影响。研究发现:1三峡库区近岸地壳垂直形变与水库水位呈负相关关系,大地水准面与水库水位呈正相关关系;水位上升,长江近岸地面水平向内形变,方向指向江心;2三峡水库蓄水造成的地壳垂直形变最大可达35mm左右,大地水准面形变最大值在8mm左右,而对库区地壳水平形变影响不超过0.5mm;3出现形变最大值的地点是忠县环湾一带,而并非是三峡大坝周边。     

Improving Orthometric Heights Using Precise GPS Measurements

The vertical component obtained from the Global Positioning System (GPS) observations is from the ellipsoid (a mathematical surface), and therefore needs to be converted to the orthometric height, which is from the geoid (represented by the mean sea level). The common practice is to use existing bench marks (around the four corners of a project area and interpolate for the rest of the area), but in many areas bench marks may not be available, in which case an existing geoid undulation is used. Present available global geoid undulation values are not generally as detailed as needed, and in many areas they are not known better than ±1 to ±5 m, because of many limitations. This article explains the difficulties encountered in obtaining precise geoid undulation with some example computations, and proposes a technique of applying corrections to the best available global geoid undulations using detailed free-air gravity anomalies (within a 2° × 2° area) to get relative centimeter accuracy. Several test computations have been performed to decide the optimal block sizes and the effective spherical distances to compute the regional and the local effects of gravity anomalies on geoid undulations by using the Stokes integral. In one test computation a 2° × 2° area was subdivided into smaller surface elements. A difference of 37.34 ± 1.6 cm in geoid undulation was obtained over the same 2° × 2° area when 1° × 1° block sizes were replaced by a combination of 5' × 5' and 1' × 1' subdivision integration elements (block sizes).     

利用等效点质量进行(似)大地水准面拟合

基于等效源原理,提出了一种半自由点质量模型,并给出了顾及相邻点空间关系构造虚拟点质量的简单快速迭代算法。实验结果表明,利用该点质量模型对离散GPS/水准观测数据进行拟合是可行的。     

大地水准面差距计算方法的研究

本文首先证明了三种大地水准面差距计算方法(迈塞尔方法、文策尔方法、最小二乘配置法)之间的关系。通过对某盆地的大地水准面差距的计算及和多普勒结果的比较,得到了一些对计算我国大地水准面差距有益的结论。