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本文介绍了GRE4电子手簿数据转换程序设计的过程以及该程序的结构和使用协议。程序的输出为测点坐标数据文件,可为CASS3.0成图软件直接调用。程序界面友好,操作简便。本研究对充分发挥GRE4的作用有一定的现实意义。 相似文献
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3维矢量结构GIS拓扑关系研究3DVECTORSTRUCTUREGISTOPOLOGICALRELATIONSHIPRESEARCH李青元(中国测绘科学研究院,北京,100039)该论文的目的是对3维矢量结构GIS(地理信息系统)的拓扑关系进行研究。... 相似文献
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全球定位系统(GPS)及其在高等级道路勘测中的应用GLOBALPOSITIONINGSYSTEM(GPS)ANDITSAPPLICATIONTOHIGH-GRADEROADRECONNAISSANCESURVEY姚连璧(同济大学测量与国土信息工程系,... 相似文献
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作者曾经利用扫描矢量化软件I/RASB和I/GEOVEC在GIS和数字地图中进行了各种各样的应用研究。本文着重介绍I/RASB和I/GEOVEC等在GIS和地图数字化中的应用方法,包括矢量文件和光栅文件。 相似文献
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本文简要介绍了有一种以MICROSTATION为图形平台,GEOGRAPHICS为基础GIS软件的地下管网信息系统,探讨了GEOGRAPHICS的几个重要特点,以及在开发地下管网信息系统遇到的几个关键问题 相似文献
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联合多种卫星测高数据分析全球和中国海海平面变化 总被引:14,自引:0,他引:14
利用了7年的T/P数据(第9周期至第249周期)、4年的ERS2数据(第0周期至第44周期)和Geosat精刻度重复任务(ERM)数据,由共线法研究了全球海平面变化和中国海域海平面变化。测高数据的逆气压改正采用了每个周期的平均大气压重新计算,对T/P和ERS2两种数据源计算的1995~1999年海平面变化作了相应的比较。 相似文献
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地理信息系统给许多应用领域如文档编辑、规划、分析和建模提供基础数据,这些信息描述产生于制图产品-地图。制图综合是从基础数据库获取不同比例尺和不同主题的地图的主要方法。本文将讲述INTERGRAPH的产品MAPGEN(MGE地图综合)在这个技术领域的成果。 相似文献
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精密单点定位(PPP)依靠IGS分析中心发布的精密星历和钟差产品进行高精度绝对定位,由于IGS最终精
密星历的发布有2~3周的延迟,无法满足高时效的生产需求,而不同的分析中心则会在1~2d之内发布快速精密
星历,因此对不同分析中心发布的快速精密轨道和钟差产品精度进行研究,并通过静态和动态精密单点定位实验验
证分析,旨在实际应用中根据需求选择对应分析中心的精密产品。结果表明,不同分析中心的精密轨道和钟差产品
精度存在差异,其中IGR最优,GFZ与EMR稍差;精密单点定位实验中,EMR、ESA、GFZ产品收敛
速度快、定位精度高,ESA整体定位性能最优。 相似文献
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基于“4D”技术的洪灾预报与评估区域示范研究 总被引:1,自引:0,他引:1
“4D”是美国联邦地质调查局(USGS)新近推出的被称之为“九十年代水平上的遥感与地理信息系统集成”的技术,“4D”包括DEM(数字高程模型)、DOQ(数字正射影像)、DRG(数字栅格地图)和DTI(数字专题信息)。中国测绘科学研究院在国家“九五”重中之重科技攻关及国家测绘局“九五”重大科技攻关项目经费资助下开展了基于“4D”技术的洪灾预报与评估区域示范研究工作。本文介绍了利用“4D”技术构建孕灾 相似文献
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网络建设与维护管理是移动通信行业日常业务工作的重要内容,由于移动通信电波传播对地理环境存在极强的依赖性,因此利用高精度的专题数字地图进行网络规划和优化成为移动通信网络建设管理的必然趋势。本文综合近年来面向移动通信网络建设数字地图的生产应用实践,结合当前技术发展导向分析,旨在探索面向移动通信网络建设数字地图生产与集成的有效途径。首先分析了移动通信网络建设的主要内容,继而总结归纳了面向移动通信网络建设的数字地图的数据组成,然后针对面向移动通信网络建设数字地图的需求特点及精度要求,给出了面向移动通信网络建设数字地图的生产工艺流程、质量控制流程及数据集成方法,最后介绍了面向移动通信网络建设数字地图的应用实例及效果分析。 相似文献
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VC++6.0环境下GPS接收机串口通信的实现 总被引:3,自引:0,他引:3
首先简单介绍了GPS接收机串口通信的基本概念,然后通过实例详细介绍了计算机与GPS接收机进行数据传输的两种方法:一种是使用Win32 API通信函数的文件读写方式;另一种是通过VC^ 6.0提供的MSComm控件实现。 相似文献
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Ramón Piedrafita Rubén Béjar Rubén Blasco Alvaro Marco F. Javier Zarazaga-Soria 《International Journal of Digital Earth》2018,11(8):761-782
In the current world, it is easy to listen that everybody and everything is connected. Over this connected world, the concept of location-based services has grown in order to provide digital services in everyplace and at every time. Nevertheless, this is not 100% true because the connection is not guaranteed for many people and in many places. These are the Degraded Communications Environments (DCE), environments where the availability of high-speed communications is not guaranteed in at least the 75% of the time. This paper works over the experience of a previous work in developing light protocols that do not need broadband for communication. This work provides an extension of these protocols for the inclusion of mobile devices as elements of the communication process and a set of libraries to allow the development of applications in DCE. The work done has involved the development of two frameworks: an Android framework that makes the incorporation of Android devices easier and a server-based framework that provides the server side for the development of the referred applications. A use case that uses these two frameworks has been developed. Finally, all technology developed is available throw a public Git repository. 相似文献
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In recent years in India, deregulation has opened the telecommunications market up to new arenas putting pressure on existing organizations to become more efficient. New technologies such as fibre optic cables, efficient terrestrial broadcasting and satellites are offering greatly increased bandwidth. However, the ever-increasing demand to provide low-cost and large area coverage with high reception quality has forced these industries to explore advanced optimization strategies for their network planning. The telecommunications companies have begun to recognize that many of their work practices have spatial elements and data can be used more efficiently. In the present study, a planning strategy for establishing a network of towers for the purpose of mobile communications using remote sensing and raster GIS is demonstrated. In particular, this study addresses how to develop a surface model using IRS-1C PAN stereo pair. This information derived from the satellite data was integrated with raster GIS GRID modelling. The study clearly demonstrates that the IRS data could be utilized for planning a suitable network of towers for telecom applications. 相似文献
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介绍了企业网IP电话系统的设计和实现方法。系统利用企业网这一高效的通讯介质 ,并针对目前Ethernet的特性进行优化 ,辅以三层数据应用实现了局域网内的话音文字通讯和局域网与PSTN电话网间的拨号及话音通讯。 相似文献
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Satellite clock bias estimation for iGPS 总被引:4,自引:0,他引:4
John Pratt Penina Axelrad Kristine M. Larson Bruno Lesage Richard Gerren Nicholas DiOrio 《GPS Solutions》2013,17(3):381-389
The High Integrity GPS program seeks to provide enhanced navigation performance by combining conventional GPS with a communications and ranging broadcast from the Iridium® Communications System. Through clock and message aiding, it would enable existing GPS receivers to acquire and track in more challenging environments. As is the case for standard GPS, accurate and precise timing is key to performance. An approach is presented for estimating the bias of each Iridium satellite clock using satellite-to-ground and satellite-to-satellite measurements. The satellite clock bias estimates are based on a Kalman filter that incorporates code-type observations from the measurements at 10 s intervals. Filter parameters are set based on the expected behavior of the clocks, allowing for discontinuous bias and frequency adjustments due to ground commands. Typical results show the current filter to be accurate to within 200 ns while always meeting the initial system specification of half a microsecond. 相似文献