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电子航道图的标准建设与生产应用关系到内河航运的高质量发展动能.分析了电子航道图标准的现状及存在的问题,建立了现有电子航道图标准体系及内河航道地理信息要素的分类方法,结合电子航道图核心要素,建立了典型应用场景,通过完善电子航道图数据标准体系和精细化生产应用,不断提升综合立体交通网的水运比较优势. 相似文献
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本文以长江数字航道与智能航运建设示范工程(南京至浏河口河段)为依托,介绍了国际标准电子海图的发展情况,着重阐述了基于S-57编码的长江内河电子航道图(iENCs)的关键技术,以保证长江电子航道图的生产、应用遵循相关国际标准,同时也尽量体现长江内河流域的航道特征。 相似文献
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电子航道图与航标遥测监控系统 总被引:1,自引:0,他引:1
"数字航道"建设的主要目标在于应用信息技术平台保障航道安全、提高航务管理水平.作为航道管理中的重要导航设施航标灯(船),对其工作状态、空间位置进行远距离全天候监测与遥控是"数字航道"建设的主要内容.航标遥测监控系统集成无线通讯、传感器、空间信息处理等技术,实现航标信息的实时采集与传输,异常状况的报警及统计等功能.电子航道图运用事件驱动型地图表达、时空变化特征地图表达、多尺度地图表达及国际电子海图S57/S52标准表达等关键技术,为监控航标提供地理定位背景,并支持遥控监测中的空间信息查询、分析等功能. 相似文献
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航道疏浚工程竣工验收数字化测量技术研究 总被引:1,自引:0,他引:1
根据航道疏浚工程竣工验收数字化测量作业流程,阐述了航道疏浚工程竣工验收测量方法和技巧,并借助测量成图软件CASS,绘制航道疏浚工程竣工图,并对绘制过程中的相关技术问题进行了探讨。 相似文献
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前一讲已经述及,用机助成图方式进行城市地形测图的数据采集可由航摄象片和人工现场采集两种方式。本讲主要介绍人工现场采集数据为大比例尺数字测图的一些基本概念及某些相关的问题。大比例尺地面数字测图的成图方法流程见图1。外业数据采集是用电子速测仪和电子记录器(或便携机)组成。在测图现场由人工照难测图特征点,并将数据逐点存入电子记录器中。数据中的观测值则由电子速测仪(如全站仅或测距仪加经纬仪)获取。数据传输是将电子记录器记录的数据用通讯的方式传输给计算机,再由计算机软件完成数据处理和等高线的自动生成。为了… 相似文献
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《International Journal of Digital Earth》2013,6(1):80-87
Abstract Cultures throughout the world are associating with the rivers. People depend upon the rivers and their tributaries for food, water, transport, and many other aspects of their daily lives. Unfortunately, human beings have not calculated the accurate lengths for the great rivers even today. The lengths of the rivers are very different in popular textbooks, magazines, atlases and encyclopedias, etc. To accurately determine the lengths of the principal rivers of the world, the combination of satellite image analysis and field investigations to the source regions is proposed in this paper. The lengths of the Nile, Amazon, Yangtze, Mississippi, Yellow, Ob, Yenisey, Amur, Congo and Mekong, with lengths over or close to 5000 km, were calculated using the proposed method. The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable. 相似文献
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软科学这一术语是70年代在国外提出的.然而30多年以来,它在国外不仅未得到普遍的承认,而且对软科学的定义也还未能达成大体上一致的共识.而在改革开放后的中国,出于决策科学化和民主化的需要,经过一些领导人的提倡和支持,特别是通过1986年召开的软科学座谈会及1994年召开的全国软科学工作会议,软科学事业得到了蓬勃的发展.据初步统计,截止1998年底全国共有软科学研究机构1224个,研究人员32655人,初步形成了一支较为强大的研究队伍,并取得了数百项覆盖多个领域的研究成果,为支持各级各类的决策发挥了一定的作用. 相似文献
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Tobias Nilsson Benedikt Soja Kyriakos Balidakis Maria Karbon Robert Heinkelmann Zhiguo Deng Harald Schuh 《Journal of Geodesy》2017,91(7):857-866
The very long baseline interferometry (VLBI) Intensive sessions are typically 1-h and single-baseline VLBI sessions, specifically designed to yield low-latency estimates of UT1-UTC. In this work, we investigate what accuracy is obtained from these sessions and how it can be improved. In particular, we study the modeling of the troposphere in the data analysis. The impact of including external information on the zenith wet delays (ZWD) and tropospheric gradients from GPS or numerical weather prediction models is studied. Additionally, we test estimating tropospheric gradients in the data analysis, which is normally not done. To evaluate the results, we compared the UT1-UTC values from the Intensives to those from simultaneous 24-h VLBI session. Furthermore, we calculated length of day (LOD) estimates using the UT1-UTC values from consecutive Intensives and compared these to the LOD estimated by GPS. We find that there is not much benefit in using external ZWD; however, including external information on the gradients improves the agreement with the reference data. If gradients are estimated in the data analysis, and appropriate constraints are applied, the WRMS difference w.r.t. UT1-UTC from 24-h sessions is reduced by 5% and the WRMS difference w.r.t. the LOD from GPS by up to 12%. The best agreement between Intensives and the reference time series is obtained when using both external gradients from GPS and additionally estimating gradients in the data analysis. 相似文献
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In this letter, we are trying to resolve the electromagnetic problem for the movements of the superconducting particles of the protoplanetary cloud in the magnetic field of Saturn. The force of levitation (Meissner-Ochsenfeld phenomenon) is introduced to the field of planetary science for the first time. It is shown from our theoretical analysis that rings of Saturn might have a superconducting origin, and rings might levitate within magnetic equator plane of the planet. 相似文献
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跟踪世界发展动态 致力地球重力场研究 总被引:12,自引:6,他引:12
宁津生 《武汉大学学报(信息科学版)》2001,26(6):471-475
比较系统、扼要地叙述了笔者所在单位40余年来坚持跟踪世界发展动态,致力于地球重力场理论和方法的研究,并从教学和生产需要出发,在地球重力场研究方面所获得的一些有理论意义和实用价值的成果。 相似文献