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介绍多波束测深系统的构成、工作原理、作业方法,以及RTK三维水深测量技术的理论依据,通过在渤海湾航道水深测量的工作实践,证明使用多波束系统结合RTK三维水深测量技术联合作业,可以得到令人满意的测量精度。 相似文献
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传统载人测量船吃水深,无法进行浅海水深测量,因此吃水极浅的无人船为近海水深测量提供了新途径。本文利用无人船无验潮测深与GNSS网络RTK技术,在不同的风浪条件下进行了近海水深测量试验;并从轨迹跟踪与水深测量精度方面,定量评估了无人船野外作业的抗风浪能力。结果表明:0~0.3 m浪、0~2级风是无人船近海测量作业的理想风浪阈值;风浪过大会导致无人船路径跟踪精度较低,难以保证测量成果质量。在理想的风浪阈值内,无人船无验潮测深技术能实现近海水深的高精度测量,满足相关测深规范要求,在近海水深与海底地形测量中具有广阔的应用前景。 相似文献
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结合多个清淤测绘项目的实施,探讨了测量过程中通过提高平面定位、水深测量和水位观测三个方面的测量精度,特别是通过水深测量过程控制来提高测深精度。总结了项目实例中采用的技术方案、实施方案、内业处理和数据分析等技术,为我国测量人员在类似测绘项目中的实施提供有益的参考。 相似文献
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在偏远水域进行海图测量一直是个难题,遥感反演水深技术的发展弥补了传统海图测量的局限性.本文重点讨论了基于Stumpf模型和多时相方法的多光谱卫星遥感水深反演技术,分析了影响其质量的主要因素,通过在海南岛偏远水域的工程实践案例,评估和验证了其一般精度和可靠性,认为其结果除可用于测量和规划海图之外,还可作为海图现势性评估、海底变化检测和测量优先级确定的工具,为在偏远地区、未测量区域以及动态变化水域改进海图测量提供了新的途径. 相似文献
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论述了RTK结合测深仪实现无验潮测深的原理和方法;对无验潮测深技术中影响水深测量成果精度的几个问题进行了分析探讨,并提出了实用可行的控制方法,减少水深测量过程中的累计误差以提高测量精度。 相似文献
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为解决南黄海辐射沙脊群海域独特地理、水文条件下水深测量的现实困难,提高测量精度,本文将GPS动态后处理技术(GPS-PPK)运用于该海域的水下地形测量工作中。GPS-PPK技术具有控制距离远、无需实时数据传输的优点,是船载一体化水深测量时三维精确定位的理想选择。本文在数据结构、GPS-PPK信号频谱定量分析的基础上,提出了GPS-PPK截频滤波及数据匹配方案,使其适用于该海区水深测量并进一步提高测量精度。实验表明,整套方案操作便捷、有效可靠,测量精度较传统验潮方案更高。同时,远距离无验潮测量,节省了大量人力物力,非常值得在广阔的南黄海辐射沙脊群海域浅水环境下推广使用。 相似文献
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水深测量是海洋测绘的重要内容。传统的船载多波束回声测深方法虽然具有较高的测量精度,但无法进入沿岸浅水区域和海礁密集区域。近年来,机载LiDAR的出现和发展填补了沿海浅水区域水深测量技术的空白,已成为一种快速高效的水深及海底地形探测方法。本文介绍了现有的几种有代表性的机载激光测深系统,给出了机载激光测深数据处理流程,分析了机载激光测深的关键技术,归纳并总结了该技术目前所存在的技术难点和未来的发展趋势。 相似文献
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水下测量是测绘工作的一个重要组成部分,利用水下测量技术可获取水下地形、河道纵横断面、水深等数据,保障水域施工、水下救援、河道疏浚等工作的正常开展.相较于传统的人工水下测量手段,搭载声呐设备的无人船水下测量系统以其测量速度快、人工成本低、安全系数高、精度高等特点迅速成为水下测量工作所使用的主流技术,并在很多项目中开展应用.在应用过程中发现,无人船测量环境较为复杂,一般的技术流程往往难以满足实际需要.因此,本文从单波束无人船的测量原理出发,结合实际案例,探讨单波束无人船在复杂水域地形测量中存在的问题及解决方式,形成无人船在复杂水域地形测量的技术流程. 相似文献
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针对双介质立体摄影测量中水面高程不确定性带来的测深误差,本文提出了主被动光学卫星遥感数据融合浅海水深测量的技术路线,探讨了主动ICESat-2激光测高数据与被动WorldView-3立体像对数据融合的测深模型。首先通过ICESat-2激光测高数据提取海面高程作为WorldView-3立体像对数据水面高程纠正的起算位置,然后利用区域网平差的二次多项式加入适当的水深改正量。在我国南海岛礁开展了主被动光学卫星遥感数据融合进行浅海水深测量试验。结果表明,主被动融合测深模型的均方根误差(RMSE)小于0.70 m,实现了高精度、无实测控制点的浅海水深测量。 相似文献
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Monitoring drought dynamics in the Aravalli region (India) using different indices based on ground and remote sensing data 总被引：5，自引：0，他引：5
C. Bhuiyan R.P. Singh F.N. Kogan 《International Journal of Applied Earth Observation and Geoinformation》2006,8(4):289-302
The hard-rock hilly Aravalli terrain of Rajasthan province of India suffers with frequent drought due to poor and delayed monsoon, abnormally high summer-temperature and insufficient water resources. In the present study, detailed analysis of meteorological and hydrological data of the Aravalli region has been carried out for the years 1984–2003. Standardised Precipitation Index (SPI) has been used to quantify the precipitation deficit. Standardised Water-Level Index (SWI) has been developed to assess ground-water recharge-deficit. Vegetative drought indices like Vegetation Condition Index (VCI) and Temperature Condition Index (TCI) and Vegetation Health Index (VHI) have been computed using NDVI values obtained from Global Vegetation Index (GVI) and thermal channel data of NOAA AVHRR satellite. Detailed analyses of spatial and temporal drought dynamics during monsoon and non-monsoon seasons have been carried out through drought index maps generated in Geographic Information Systems (GIS) environment. Analysis and interpretation of these maps reveal that negative SPI anomalies not always correspond to drought. In the Aravalli region, aquifer-stress shifts its position time to time, and in certain pockets it is more frequent. In comparison to hydrological stress, vegetative stress in the Aravalli region is found to be slower to begin but quicker to withdraw. 相似文献
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地理数据库的关系模型及其实现 总被引：1，自引：0，他引：1
本文从以图论观点分析地理实体入手,系统阐述了地理数据库关系模型的设计法和过程。作者于1984年4～9月间在微型机上设计建立了关系型地理数据库的实方验系统(RGDB)。该系统采用了本文提出的关系模型,采用了可动态扩库的子库组合结构,这种结构具有灵活性和提高空间利用率的优点。RGDB含有多种功能的数据操作命令,除了具有一般检索功能外,还能进行“开窗”选取和十分“自由”的映象选取。本文对RGDB系统的主要性能和实现途径作了扼要介绍。 相似文献
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随着城市面貌日新月异,地下管网的建设也在持续推进,作为城市的地下“神经网络”,全天24 h保障城市的正常运转和发展。本文以实现城市管网管理系统的高可用、无插件、智能化为目标,采用“地上地下一体”“二三维一体”的设计理念,研究基于WebGL的三维智慧管网系统的关键技术,实现了管线设施管理的信息数字化、空间化与图形化。 相似文献
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SVG是一种基于XML的用来描述二维矢量图形和矢量/栅格混合图形的标记语言,虽然SVG不是为了面向地理空间数据发布而制定的标准,但它的许多特性都能被广泛地应用到WebGIS中,从而实现矢量WebGIS。由于SVG通过简单的文本语句描述矢量图像,所以SVG通常数据量很小,并且SVG支持GZIP压缩,所以基于SVG构建WebGIS能减轻网络传输负载,加快地图显示速度。SVG内置了对JavaScript的支持,且SVG可通过DOM解析映像成内存中的树型结构,所以客户层可通过JavaScript对DOM的操作实现对地图的缩放、漫游、查询、图层控制等交互操作。 相似文献
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本文在讨论DDE技术的基础上，对MapInfo的DDE机制的实现作了探讨和分析。根据技园区域GIS的实际开发工作，介绍了利用DDE技术在MapInfo中成功地集成Foxpro和Autocad. 相似文献
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遥感技术在土地利用动态监测中的应用 总被引：8，自引：0，他引：8
金时华 《测绘与空间地理信息》2006,29(1):98-101
主要论述遥感技术在土地监测中的应用,以某地区土地利用动态遥感监测研究项目的运作过程为例进行阐述。首先介绍了土地利用动态监测的具体内容和技术路线。其次,对数据预处理与信息采集的方法与手段进行了探讨。最后,对作业的内、外业主要过程以及应提交的成果作了介绍。 相似文献
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Automatic 3D extraction of building roofs from remotely sensed data is important for many applications including city modelling. This paper proposes a new method for automatic 3D roof extraction through an effective integration of LIDAR (Light Detection And Ranging) data and multispectral orthoimagery. Using the ground height from a DEM (Digital Elevation Model), the raw LIDAR points are separated into two groups. The first group contains the ground points that are exploited to constitute a ‘ground mask’. The second group contains the non-ground points which are segmented using an innovative image line guided segmentation technique to extract the roof planes. The image lines are extracted from the grey-scale version of the orthoimage and then classified into several classes such as ‘ground’, ‘tree’, ‘roof edge’ and ‘roof ridge’ using the ground mask and colour and texture information from the orthoimagery. During segmentation of the non-ground LIDAR points, the lines from the latter two classes are used as baselines to locate the nearby LIDAR points of the neighbouring planes. For each plane a robust seed region is thereby defined using the nearby non-ground LIDAR points of a baseline and this region is iteratively grown to extract the complete roof plane. Finally, a newly proposed rule-based procedure is applied to remove planes constructed on trees. Experimental results show that the proposed method can successfully remove vegetation and so offers high extraction rates. 相似文献
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遥感和GIS技术应用于伊拉克南部Basrah省土地利用/覆盖变化及城市扩张研究(英文) 总被引：2，自引：0，他引：2
In recent years, land use/cover dynamic change has become a key subject that needs to be dealt with in the study of global
environmental change. In this paper, remote sensing and geographic information systems (GIS) are integrated to monitor, map,
and quantify the land use/cover change in the southern part of Iraq (Basrah Province was taken as a case) by using a 1:250
000 mapping scale. Remote sensing and GIS software were used to classify Landsat TM in 1990 and Landsat ETM+ in 2003 imagery
into five land use and land cover (LULC) classes: vegetation, sand, urban area, unused land, and water bodies. Supervised
classification and normalized difference build-up index (NDBI) were used respectively to retrieve its urban boundary. An accuracy
assessment was performed on the 2003 LULC map to determine the reliability of the map. Finally, GIS software was used to quantify
and illustrate the various LULC conversions that took place over the 13-year span of time. Results showed that the urban area
had increased by the rate of 1.2% per year, with area expansion from 3 299.1 km2 in 1990 to 3 794.9 km2 in 2003. Large vegetation area in the north and southeast were converted into urban construction land. The land use/cover
changes of Basrah Province were mainly caused by rapid development of the urban economy and population immigration from the
countryside. In addition, the former government policy of “returning farmland to transportation and huge expansion in military
camps” was the major driving force for vegetation land change. The paper concludes that remote sensing and GIS can be used
to create LULC maps. It also notes that the maps generated can be used to delineate the changes that take place over time.
Supported by the Al-Basrah University, Iraq, the Geo-information Science and Technology Program (No. IRT 0438)China). 相似文献