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41.
开源GIS进展及其典型应用研究 总被引:7,自引:0,他引:7
近年来,开源GIS软件取得迅猛发展,越来越多的科研机构、企业和组织开展了开源GIS软件开发和应用研究。本文首先综述了当前主流的开源G1S软件及其典型应用,讨论了开源GIS软件版权许可形式;其次,分别从模块功能、体系架构和开发使用环境等方面分析了主流开源桌面GIS软件和WebGIS的特点,并提出研发和教学方面开源GIS软件选择的建议;最后,讨论了基于GeoServer、Nasa World Wind、MapServer和SharpMap四种开源GIS软件在地图制图、3维可视化表达、网络地理信息服务和移动GIS软件等方面的典型应用实例,对开源GIS的应用和发展前景进行了展望。 相似文献
42.
通过对精密水准资料的二级检查,剔除其中的纰漏与错误,把一份完整、全面、优秀的资料交与上级部门。 相似文献
43.
We developed a method to produce a 3-D voxel-based solid model of a tree based on portable scanning lidar data for accurate estimation of the volume of the woody material. First, we obtained lidar measurements with a high laser pulse density from several measurement positions around the target, a Japanese zelkova tree. Next, we converted lidar-derived point-cloud data for the target into voxels. The voxel size was 0.5 cm × 0.5 cm × 0.5 cm. Then, we used differences in the spatial distribution of voxels to separate the stem and large branches (diameter > 1 cm) from small branches (diameter ⩽ 1 cm). We classified the voxels into sets corresponding to the stem and to each large branch and then interpolated voxels to fill out their surfaces and their interiors. We then merged the stem and large branches with the small branches. The resultant solid model of the entire tree was composed of consecutive voxels that filled the outer surface and the interior of the stem and large branches, and a cloud of voxels equivalent to small branches that were discretely scattered in mainly the upper part of the target. Using this model, we estimated the woody material volume by counting the number of voxels in each part and multiplying the number of voxels by the unit voxel volume (0.13 cm3). The percentage error of the volume of the stem and part of a large branch was 0.5%. The estimation error of a certain part of the small branches was 34.0%. 相似文献
44.
Imaging spectroscopy is an emerging and versatile technique that finds applications in diverse fields concerned with remote identification, discrimination and mapping of materials. The large amount of spectral data produced by hyperspectral imaging necessitates the development of automated techniques that convert imagery directly into thematic maps. Spectral library search method, a method of choice for organic compound identification by the mass spectroscopy, has caught the attention of researchers as one of the appropriate methods for an efficient exploitation of high quality spectral data available from the hyperspectral imaging systems. Given the apparent increase in the number of papers appearing on the subject as well as the variety of methods proposed, it is reasonable to say that the field of automated interpretation of reflectance spectral data has passed its infancy now gaining important space in the scientific community. We present an overall view of the literature relevant to the development of library search method, the various search algorithms and systems available in the purview for developing an automated hyperspectral data analysis system for material identification. 相似文献
45.
Seema Mehra Parihar Soma Sarkar Amitava Dutta Shilpi Sharma Tanushree Dutta 《国际地球制图》2013,28(3):273-287
The East Kolkata Wetlands is a unique resource recovery system. The Ramsar Convention recognized it as a ‘Wetland of International Importance’ in August 2002. However, the long-term resource exploitation and land use changes in the dynamic ecosystem have resulted in non-linear environmental responses. This is an attempt using open source remote sensing datasets to capture the spatio-temporal transformation of the wetland resulting from various anthropogenic activities. Landsat MSS and TM imageries of 1973, 1980, 1989, 2001 and 2010 were classified using Maximum Likelihood Classifier to monitor the wetland change; however, to study wetland dynamics, the post-classification wetland change detection maps have been generated for two temporal phases, i.e. 1973–1989 and 1989–2010. This study finds that the area under wetlands has reduced comprehensively in the past 40 years due to the conversion of wetlands into various other uses such as urban expansion of the Kolkata metropolitan city. 相似文献
46.
GIS是地理信息服务的有效工具和手段。本文基于开源GIS软件Geoserver和Leaflet,首先,介绍了它们的特点和优势,阐述了地理信息服务的规范;然后,提出了构建与调用地理信息服务的体系框架,研究了服务构建和调用等关键技术;最后,基于烟台市地图数据进行实验,取得了满意的效果。 相似文献
47.
基于钻孔数据的三维地质建模与可视化研究 总被引:7,自引:1,他引:7
三维地质模型能够完整准确地表达复杂地质现象的边界条件及地质体内含的各种地质构造,直观地再现地质单元的空间展布及其相互关系,最大限度地提高地质分析的直观性和准确性,因此三维地质建模已引起地质、采矿、岩土工程等诸多领域的日益重视。笔者在综合考察多种建模方法的基础上,结合工程实践,提出了一种实用的工程地质三维建模实施方法。该方法以钻孔资料和地质剖面数据为三维地质建模的源数据,允许用户手工修正模型剖面地层分界线,从而实现对建模过程的干预和控制,克服了单纯依靠钻孔数据建模结果不精确且难以修正的问题。最后,通过一个研究实例展示了该方法的实际建模效果。 相似文献
48.
Open source, spatial analysis, and activity-travel behaviour research: capabilities of the aspace package 总被引:2,自引:0,他引:2
This paper reports on recent experience with the development of aspace, an Open Source (OS) library for the geographic visualization and analysis of activity-travel behaviour. The paper begins
with an overview of recent progress with respect to the convergence of Open Source technology, spatial analysis, and travel
behaviour research. The remainder of the paper focuses on aspace; a collection of functions that, when combined with data describing the geographical location of daily activities, can be
used to visualize and describe spatial properties of individual and household activity spaces. These properties include: size,
orientation, shape, and the geographical dispersion of activity locations contained within the activity space. Several planar
geometries are used to transform measurable spatial properties into intuitive objects for visualizing spatial patterns of
activity participation. Experiments are conducted, using data from the first wave of the 2003 Toronto Travel Activity Panel
Survey, to demonstrate the potential application of aspace for basic and applied policy-based research into activity-travel behaviour. The toolkit is distributed as a downloadable
‘package’ from the Open Source R Project for Statistical Computing.
相似文献
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