多种角度比较SIFT、SURF、BRISK、ORB、FREAK算法

SIFT、SURF、BRISK、ORB、FREAK等图像特征匹配算法具有不同的鲁棒性,本文利用Mikolajczyk和Schmid所提供的数据集,对这几种算法从匹配速度,应对图像旋转变换、模糊变换、光照变换、尺度变换、视角变换时表现出的鲁棒性等角度进行比较。本文采用的评价指标是两幅图像中成功匹配的特征点对数。经比较分析后发现,SURF和FREAK算法表现出的鲁棒性较为全面。     

中州都市尽春风——河南郑州、信阳、漯河、商丘、新郑、新县考察散记

2月17日至2月22日,中国国土经济学研究会、全国中小城市生态环境建设实验区办公室一行七人,应河南省郑州市惠济区、信阳市、漯河市、商丘市人民政府的邀请,在浓浓的春意中走访了六个城市,共商全国中小城市生态环境建设实验区持续发展大计。来去五天,行色匆匆,我们看到了曾经被黄河水肆虐的茂密森林,碧波荡漾的南湾湖,气势宏伟的大河广场,双汇集团那现代化的生产线,黄帝故里恢弘的轩辕宫,悠悠五千年的商丘古城,坚持学习《毛泽东选集》、提倡共产主义精神的南街村,因实施"四位一体"工程而干净整洁的村庄,基层领导求贤若渴真诚的目光……短短的…     

辽宁、山东、广东、北京等省、市测绘学会恢复活动

【本刊讯】在全国科学大会精神鼓舞下，在各省、市党委和科协的关怀下，辽宁省、山东省、广东省和北京市的测绘学会已先后于今年三、四月间恢复了活动，深受各部门的测绘工作者欢迎。     

星威测量型GPS--高精度、高性能、高集成、低功耗、低价格

星威高精度测量型GPS系列产品,主要部件全部采用进口,后处理软件采用武汉测绘科技大学商品化软件,软件具有基线向量解算、网平差、成图等功能,GPS接收机同国外公司同类产品兼容.     

深圳盗车、东莞改装、卫星追踪、捣毁贼窝

2000年9月19日上午,深圳市公安局刑警支队和东莞市公安局110紧急联合行动,在“赛格车圣”全球卫星跟踪系统的引导下,从东莞市虎门镇一盗车团伙的窝点,将被盗4小时已经部分改装的一辆本田雅阁轿车追回。     

我国钾、镁、钾、硼矿产资源的可持续发展

一、我国钾、硼、锂、镁资源形成条件和远景分析及盐湖的意义　　我国已探明的钾盐储量主要分布在青海柴达木盆地和新疆罗布泊的 1 1个现代盐湖中。青海柴达木盆地KCl的资源总量为 7 1 3亿t,其次是新疆罗布泊 ,初步圈定KCl资源量 2 9亿t,第三是西藏35个特种 (钾锂硼 )盐湖 ,KC     

坚持为民、利民、便民 努力为人民群众办实事、解难事、做好事

“三个代表”重要思想的本质是立党为公、执政为民。在工作中要牢牢把握立党为公、执政为民，坚持权为民所用、情为民所系、利为民所谋，始终把依法维护好、实现好、发展好人民群众的利益，作为国土资源管理工作的出发点和落脚点，时时想着群众，事事为了群众，切实为人民群众诚心诚意办实事、尽心竭力解难事、坚持不懈做好事。     

BeiDou、Galileo、GLONASS、GPS多系统融合精密单点

随着中国BeiDou系统与欧盟Galileo系统的出现以及俄罗斯GLONASS系统的恢复完善,过去单一的GPS导航卫星系统时代已经逐步过渡为多系统并存且相互兼容的全球性卫星导航系统(multi-constellation global navigation satellite systems,multi-GNSS)时代,多系统GNSS融合精密定位将成为未来GNSS精密定位技术的发展趋势。本文采用GPS、GLONASS、BeiDou、Galileo 4大卫星导航定位系统融合的精密单点定位(precise point positioning,PPP)实测数据,初步研究并分析了4系统融合PPP的定位性能。试验结果表明:在单系统观测几何构型不理想的区域,多系统融合能显著提高PPP的定位精度和收敛速度。4大系统融合的PPP收敛速度相对于单GNSS可提高30%~50%,定位精度可提高10%~30%,特别是对高程方向的贡献更为明显。此外,在卫星截止高度角大于30°的观测环境下,单系统由于可见卫星数不足导致无法连续定位,而多系统融合仍然可以获得PPP定位结果,尤其是水平方向具有较高的定位精度。这对于山区、城市以及遮挡严重的区域具有非常重要的应用价值。     

UGANDA,LAND AND SURVEY DEPARTMENT,ANNUAL REPORT, 1938

Abstract

Among colonial dependencies Uganda is but a small territory; but it is comparatively prosperous and is compact. In such circumstances the integration under one departmental organization of survey and registration and of the administration of the State's responsibilities for lands and mines proves to be a convenient and economical arrangement, which works, in the balance, to the advantage of the survey branch. The Annual Report for 1938 deals with all the activities of a diversely occupied department, which controlled revenue collections of over £56,000, and mineral exports valued at £225,000.     

GIS, expert systems, and interoperability

Integrating a GIS has been a common way to combine the functionality of two or more systems for some time. A three-dimensional model of integration is described which shows the range of linkages that can be achieved. Extremely flexible and dynamic linkages between systems can now be created through the recent advances of client/server and object-oriented technology. An expert system shell is coupled with a GIS to create a generic spatial rule-based toolbox called SES (spatial expert shell). An expert system developer using this toolbox can transparently access spatial data and relationships from a GIS by linking application objects to spatial classes. These spatial classes include methods that format and send requests to the GIS server. Thus the linkage is determined at run-time allowing a flexible interwoven interaction between the expert system and the GIS.     

Qibla,and Related,Map Projections

The qibla problem—determination of the direction to Mecca—has given rise to retro-azimuthal map projections, an interesting, albeit unusual and little known, class of map projections. Principal contributors to this subject were Craig and Hammer, both writing in 1910. A property of retro-azimuthal projections is that the parallels are bent downwards towards the equator. The resulting maps, when extended to the entire world, thus must overlap themselves. An unusual recent discovery from Iran suggests that Muslims might have been prior inventors of a similar projection, by at least several centuries. A later corollary by Schoy leads to a new "cylindrical" azimuthal map projection with parallels bending away from the equator, here illustrated for the first time.     

Categorical maps, comparisons, and confidence

The comparison of categorical maps is a common problem in several different contexts. Differences between categorical maps can be characterized and measured in a variety of ways. In 2004 we invited individuals from remote sensing, geographical information analysis, spatial modelling, and landscape ecology to participate in a virtual workshop in order to compare strategies for comparison. This revealed that the key dimensions of comparison relate to (1) the map characteristics considered, (2) the nature of the comparison, (3) the handling of geographical space, (4) the units of computed measures, and (5) the tests of significance.Ferko Csillag deceased     

Entropy,complexity, and spatial information

We pose the central problem of defining a measure of complexity, specifically for spatial systems in general, city systems in particular. The measures we adopt are based on Shannon’s (in Bell Syst Tech J 27:379–423, 623–656, 1948) definition of information. We introduce this measure and argue that increasing information is equivalent to increasing complexity, and we show that for spatial distributions, this involves a trade-off between the density of the distribution and the number of events that characterize it; as cities get bigger and are characterized by more events—more places or locations, information increases, all other things being equal. But sometimes the distribution changes at a faster rate than the number of events and thus information can decrease even if a city grows. We develop these ideas using various information measures. We first demonstrate their applicability to various distributions of population in London over the last 100 years, then to a wider region of London which is divided into bands of zones at increasing distances from the core, and finally to the evolution of the street system that characterizes the built-up area of London from 1786 to the present day. We conclude by arguing that we need to relate these measures to other measures of complexity, to choose a wider array of examples, and to extend the analysis to two-dimensional spatial systems.     

“4D”技术及其应用

介绍“４Ｄ”（即数字地面模型、数字正射影像、数字栅格地图和数字线划地图）系列产品的生产流程、关键技术、及其在耕地保护、防灾减灾救灾和城市规划等方面的应用方法。