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91.
整体平差法是一个严格而又有效的平差方法,其应用与现代计算机技术密切相关。本文介绍了整体平差法的基本原理,并以实测GPS控制网的布设为例,探讨了它在现代测量控制网建立中的具体应用及其技术优势。  相似文献   
92.
 The global positioning system (GPS) model is distinctive in the way that the unknown parameters are not only real-valued, the baseline coordinates, but also integers, the phase ambiguities. The GPS model therefore leads to a mixed integer–real-valued estimation problem. Common solutions are the float solution, which ignores the ambiguities being integers, or the fixed solution, where the ambiguities are estimated as integers and then are fixed. Confidence regions, so-called HPD (highest posterior density) regions, for the GPS baselines are derived by Bayesian statistics. They take care of the integer character of the phase ambiguities but still consider them as unknown parameters. Estimating these confidence regions leads to a numerical integration problem which is solved by Monte Carlo methods. This is computationally expensive so that approximations of the confidence regions are also developed. In an example it is shown that for a high confidence level the confidence region consists of more than one region. Received: 1 February 2001 / Accepted: 18 July 2001  相似文献   
93.
国土资源基础数据库整合与集成建库模式与实现   总被引:5,自引:0,他引:5  
国土资源基础数据库建设位于国土资源信息化建设“十五”规划中五大任务之首,在空间信息基础设施的建设中有重要意义。本文结合国土资源基础数据库数据的特点和多年的基础数据库建库研究和工程实践,分析当前基础数据库建设的现状和存在的问题,提出并说明国土资源基础数据库整合与集成建库模式及实现思路。  相似文献   
94.
Land cover map 2000 (LCM2000) is a comprehensive survey of UK broad habitats giving vector digital maps from segment-based classification of remotely sensed satellite data. This paper examines the influence of users in designing LCM2000 and the difficulties in applying a user-defined classification. It assesses problems and successes through comparisons with a sample-based field survey. These suggest that LCM2000 accuracy at broad habitat level may be around 80–85%; however, it was not possible fully to discriminate errors in LCM2000 from those of the field survey or from mismatches in scales, resolutions and survey dates. Calibration generated broad habitat cover statistics from LCM2000 data to field survey equivalence. These take full account of the heterogeneity of a study area, helping to generate accurate statistics, including those at local level where the field survey cannot operate effectively. The paper concludes that the comprehensive and extensive coverage from remote sensing comes closer than alternative methods to meeting users needs. However, it recognises that producers of remotely sensed information need to understand better the needs of users, and users need to appreciate what the technology can and cannot deliver. This paper adds some benefits of hindsight to the process of communication.  相似文献   
95.
根据在禹城站养分平衡试验场20个养分池内连续三年的试验,通过比较精确的田间试验和取样分析,探讨了估养了以禹城为代表的黄淮海平原类似地区农田生态系统氮、磷、钾营养元素的平衡。试验结果表明,在黄河冲积物母质上发育的土壤,钾的供应能力很强。在当前产量水平(12000kg/ha/a)施用钾肥无效果,并出现“奢侈性消移”。氮、磷元素尤其是有效性氮和磷明显缺乏,是影响作物生产的主要因素。养分损失的主要途径是氨  相似文献   
96.
This paper presents an account of the progress of the integration between the Danish and Swedish parts of the Öresund Region within the world of science, with emphasis on biotech. The paper is based on data from the database Science Citation Index Expanded. The amount of co-authorships produced by agents from each side of the region is analysed for a 12-year period (1994–2005) and used as an indicator to show how the integration is proceeding. Each of the co-authorships is examined to shed light on the nature of the interactions, thereby identifying the agents most involved in collaboration. Furthermore, the development in co-authorships within the region is compared to the development in co-authorships between the Öresund Region and four selected reference areas. Our findings indicate that there has been a substantial increase in both the number of co-authorships overall and within biotech solely. The rise in co-authorships between the two parts is proceeding at a faster pace than the rise in co-authorships between the Öresund Region and the reference areas. The overall results of this paper indicate a growing integration of the biotech sector in the Öresund Region.  相似文献   
97.
本文介绍了GIS与OA集成的背景,分析了四种GIS与OA松散式集成方法的优缺点。在此基础上,根据GIS与OA的无缝集成的需要,提出了GIS与OA集成一体化数据管理的方法,在保证数据安全管理与统一控制的条件下,研究了基于组件、基于中间件、基于Web Service、基于本体等多种GIS与OA的无缝集成技术。最后,简要介绍了GIS和OA集成技术的实践情况。  相似文献   
98.
跨地区空间合作开发是区域一体化发展的重要举措,有利于各地区在土地资源共享、要素自由流动的前提下促进生产力跨地区布局,实现区域协调发展。浙沪小洋山空间合作是省际毗邻区合作开发的典型案例,双方通过多次协商构建了有效的合作治理机制,对合作方式、管理运行、利益分享等重大问题作出明确的制度安排,对于长三角一体化背景下推动省际、市际毗邻区合作具有较强的启示意义。  相似文献   
99.
随着国土数据的生成和收集技术迅猛发展,海量的数据汇集到国土部门,国土资源领域悄然进入大数据时代,为适应新时期国土工作的新特点,构建数字国土,青州市国土局通过对现有数据的整合构建了城乡一体化地籍信息管理平台,建立了完善的数据采集,更新、查询和应用机制,深入挖掘了数据潜力,实现了土地数据的动态化管理与应用,有力地促进了城乡建设用地统一市场的构建,并且通过系统良好的兼容性与灵活的数据接口形式,将使其成为国土资源数据系统中的重要节点,为国土资源管理进入大数据时代迈出了坚定的一步。  相似文献   
100.
Space technologies, such as kinematic Global Positioning System (GPS), often combined with an inertial navigation system (INS), provide an efficient direct georeferencing tool for remote sensing and aerial surveying. Practically, these systems are now able to deliver high-precision orientation data for spatial data acquisition platforms in a timely manner, at relatively low cost, as compared to traditional methods. The Airborne Integrated Mapping System (AIMS (TM)), developed at The Ohio State University Center for Mapping, integrates high-resolution digital imagery, differential GPS/INS, and precise timing for high-quality data acquisition supporting large-scale mapping and other precise positioning applications. In this article, the AIMS (TM) system hardware/software configuration, its current operational capabilities, and the test results of airborne mapping of the coastal zone are presented.  相似文献   
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