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Entropy Error Model of Planar Geometry Features in gis

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Geo-Spatial Information Science 2003年第2期6卷 20-24页

作者： LI Dajun GUAN Yunlan GONG Jianya DU Daosheng LI Dajun,Ph.D candidate, National laboratory for Information engineering in {2., mapping and Remote Sensing, Wuhan University,12. Luoyu Road, Wuhan 430079,china. National laboratory for Information engineering in {2. Mapping and Remote Sensing Wuhan University Wuhan China

Positional error of line segments is usually described by using "g-band", however, its band width is in relation to the confidence level choice. In fact, given different confidence levels, a series of concentric bands can be obtained. To overcome the effect of confidence level on the error indicator, by introducing the union entropy theory, we propose an entropy error ellipse index of point, then extend it to line segment and polygon, and establish an entropy error band of line segment and an entropy error donut of polygon. The research shows that the entropy error index can be determined uniquely and is not influenced by confidence level, and that they are suitable for positional uncertainty of planar geometry features.

关键词： union entropy entropy error ellipse entropy error band entropy error donut

Storage and Spatial Variation of Phosphorus in Paddy Soils of china

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Pedosphere 2009年第6期19卷 790-798页

作者： LIN Jin-Shi SHI Xue-Zheng LU Xi-Xi YU Dong-Sheng WANG Hong-Jie ZHAO Yong-Cun SUN Wei-Xia state key {2. of Soil and Sustainable Agriculture Institute of Soil Science Chinese Academy of Sciences Nanjing 2100(78 (China) Department of Geography National University of Singapore 119260 (Singapore) Graduate University of the chinese academy of Sciences Beijing 100049 (China) College of Resources and Environment Fujian Agriculture and Forestry University Fuzhou 350002 (China)

Due to the growing concern about the agricultural phosphorus (P) losses pollution, an in-depth understanding of P in paddy soils of china would be helpful in providing a national perspective of the environmental impact of P cycling and fertility on china's farms. In this study, we evaluated the P storage and the P density of paddy soils in china, characterized the spatial variations of P among the subgroups of paddy soils and soil regions in china, and evaluated the P data using gis-based analysis, which included a newly compiled 1:1 000 000 digital soil map of china, and using 1 490 soil profiles. The available and total P densities of paddy soils were 6.7 and 698.5 g m -3 , respectively. Overall in china, the total P storage within 1 m of paddy soils was estimated to be 330.2.Tg. The P density of paddy soils varied substantially with subgroups due to the different soil water regimes such as groundwater table and soil drainage. The P availability in paddy soils, especially in surface layer, was higher in high temperature and precipitation areas. Further research is needed to examine more anthropogenic impact factors, such as increasing use of chemical fertilizer.

关键词： paddy soil database paddy soil subgroups phosphorus density phosphorus pool

基于Internet的大规模城市建筑三维场景可视化研究

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系统仿真学报 2009年第10期21卷 2965-2970,2976页

作者：何正伟吴华意陈静武汉大学测绘遥感信息工程国家重点实验室武汉430072

城市场景的构建是数字城市的基础。在互联网上实现大规模城市建筑物场景实时绘制,受到带宽瓶颈及三维可视化海量数据吞吐量的限制。通过分析其特点后,设计了适合网络传输的三维模型数据结构和充分考虑可视化效率的系统服务架构,提出了... 详细信息

城市场景的构建是数字城市的基础。在互联网上实现大规模城市建筑物场景实时绘制,受到带宽瓶颈及三维可视化海量数据吞吐量的限制。通过分析其特点后,设计了适合网络传输的三维模型数据结构和充分考虑可视化效率的系统服务架构,提出了完全层次四叉树与集合的混合结构的数据组织模型,分析和论证了构建模型依据和方法。然后,讨论了建筑物场景的调度策略和方案。开发了虚拟地球平台GeoGlobe并运用于两个应用系统。实验和应用结果表明,能在普通PC机上实现大规模建筑物场景的流畅调度、实时浏览,可视化效果和用户体验好。

关键词：网络gis 城市建筑物模型海量数据数据组织模型实时三维浏览

基于Internet的大范围三维地形实时渲染

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武汉大学学报（理学版） 2005年第S2期51卷 199-202页

作者：段炼朱欣焰武汉大学测绘遥感信息工程国家重点实验室湖北武汉430079

基于Internet、分布式计算以及计算机图形学概念,提出了使用J2.E实现基于Web的大范围三维地形实时渲染的实现方法,分析了基于Web的三维地形渲染系统的开发过程中三维地表模型的建立、场景漫游,地形块拼接等环节的关键技术.这一方法集成... 详细信息

基于Internet、分布式计算以及计算机图形学概念,提出了使用J2.E实现基于Web的大范围三维地形实时渲染的实现方法,分析了基于Web的三维地形渲染系统的开发过程中三维地表模型的建立、场景漫游,地形块拼接等环节的关键技术.这一方法集成了gis、三维地形可视化、分布式计算以及网络通信等技术,允许用户通过标准Internet浏览器来应用远程功能对DEM数据进行可视化分析.

关键词：地理信息系统网络三维三维地形可视化数字高程模型

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一种实时视景仿真中高度场地形绘制算法

系统仿真学报 2005年第1期17卷 83-86页

作者：见英叶榛清华大学计算机科学与技术系北京100084 智能技术与系统国家重点实验室北京100084

大地形的快速实时绘制对于虚拟现实、gis、飞行模拟、游戏制作等方面的应用都有着重要意义。这方面,国内外算法主要集中在视点相关连续LOD(Level of Detail)上面。对已有算法进行了综合及改进,实现了一个简单快速的大地形绘制算法。算法... 详细信息

大地形的快速实时绘制对于虚拟现实、gis、飞行模拟、游戏制作等方面的应用都有着重要意义。这方面,国内外算法主要集中在视点相关连续LOD(Level of Detail)上面。对已有算法进行了综合及改进,实现了一个简单快速的大地形绘制算法。算法中,视区剪裁采用"中点分割"的思想,结合了四又树剖分过程,提高了效率。误差控制方面,引入预处理及误差反馈的思想,并对误差进行扩散,加速了绘制同时保证了对地形细节的表现。算法对裂缝拼接也做了改进。算法运行结果良好,在普通微机上即可达到较高的帧速率和较好的绘制效果。

关键词：地形绘制多分辨率视区剪裁裂缝消除

FRACTAL DIMENSION ANALYSIS APPLIED TO THE 7 DRAINAGE BASINS AND THE FLOOD IN china

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Natural Disaster Reduction in china 2003年第1期 33-36页

作者： Yang Xiuchun 1 and Zhu Xiaohua 2.(1. key laboratory of Environmental Change and Natural Disaster, Ministry of Education of{2. and Institute of Resources Science, beijing Normal University, beijing 100875 2. College of Environment, Peking University, beijing 100871,{2.) ZhuangYan

According to the fractal theory, the fractal dimensions of the 7 drainage basins and the flood are preliminarily calculated on the basis of gis in this paper. The possible relation between the fractal dimensions of the 7 drainage basins and the flood is discussed. The following conclusions are obtained: fractal dimension is an useful parameter to depict the character of flood and it is of rich information indicating the frequency and period of flood; in the studied time period, if the numbers of flood in a drainage basin are relatively great, the fractal dimension of flood in this drainage basin is comparatively great, vice versa; when the fractal dimension of a drainage basin is relatively small, the fractal dimension of flood in this drainage basin is comparatively great, vice versa.

关键词： fractal analysis fractal dimension 7 drainage basins flood china

The research of three-dimensional numerical simulation of groundwater-flow: taking the Ejina Basin, Northwest china as example

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Research in Cold and Arid Regions 2009年第3期1卷 238-248页

作者： Qi Feng 1,2. HaiYang Xi 1, Wei Liu 1,3, JianHua Si 1,2. ZongQiang Chang 1,2. YongHong Su 1,2.1. Cold and Arid Regions Environmental and engineering Research Institute, chinese {2. of Sciences, Lanzhou, Gansu 730000, china. 2. Alashan Desert Eco-hydrology Experimental Research Station, Lanzhou, Gansu 730000, china. 3. state key laboratory of Hydrosciences and engineering, Tsinghua University, beijing 100084, china. chinese Acad Sci Cold & Arid Reg Environm & Engn Res Inst 320 West Donggang Rd Lanzhou 730000 Gansu Peoples R China Alashan Desert Ecohydrol Expt Res Stn Lanzhou 730000 Gansu Peoples R China Tsinghua Univ State Key Lab Hydrosci & Engn Beijing 100084 Peoples R China

Water is a primary controlling factor for economic development and ecological environmental protection in the inland river basins of arid western china. And it is groundwater, as the most important component of total water resources, that plays a dominant role in the development of western china. In recent years, the use-ratio of surface water has been raised, the groundwater recharge rate from surface water has been reduced, and groundwater has been exploited on a large scale. This has led to the decline of ground-water levels and the degradation of eco-environments in the Heihe watershed. Therefore, the study on the change in groundwater levels in recent years, as well as simulating and predicting groundwater levels in the future, have become very significant for im-proving the ecological environment of the Heihe River Basin, to coordinate the water contradiction among upper, middle and lower reaches of Heihe River Basin and to allocate the water resources. The purpose of this study is to analyze the groundwa-ter-level variations of the Ejina region based on a large scale, to develop and evaluate a conceptual groundwater model in Ejina Basin, to establish the groundwater flow model using the experimental observation data and combining Modular Three-Dimensional Groundwater Flow Model (MODFLOW) and {2. software, to simulate the regional hydrologic regime in re-cent 10 years and compare various water-delivery scenarios from midstream, and to determine which one would be the best plan for maintaining and recovering the groundwater levels and increasing the area of Ejina oasis. Finally this paper discusses the pos-sible vegetation changes of Ejina Basin in the future.

关键词： groundwater flow model Ejina Basin MODFLOW Heihe River

Saline-alkali land in the Yellow River Delta: amelioration zonation based on gis

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Journal of Geographical Sciences 2001年第3期11卷 313-320页

作者： GUAN Yuan-xiu, LIU Gao-huan, WANG Jin-feng (state key {2. of Resources and Environment Information System, Institute of Geographic Sciences and Natural Resources Research, CAS, beijing 100101, china) state key {2. of Resources and Environment Information System Institute of Geographic Sciences and Natural Resources Research CAS Beijing China

Soil salinization is one of the major land degradation types and has greatly influenced sustainable agricultural development. Zonation of saline-alkali land is the precondition for effective amelioration. The present situation of saline-alkali land is monitored by remote sensing image processing. Causes for land salinization are analyzed, especially the two key factors, ground water depth and its mineralization degree, are analyzed by using long-term observation data. Previously, zonation of saline-alkali soil was made descriptively and artificially. Based on the present situation of saline-alkali land, ground water depth and ground water mineralization degree, the zonation of saline-alkali land for amelioration in the Yellow River Delta was completed quantitatively. Four different types of saline-alkali land amelioration zones are delineated, namely, easy ameliorated zone, relatively difficult ameliorated zone, difficult ameliorated zone and unfavorable ameliorated zone. Countermeasures for ameliorating saline-alkali soils are put forward according to ecological conditions of different saline-alkali land zones.

关键词： gis the Yellow River Delta saline-alkali land zonation

Spatial distribution characteristics of urban thermal conditions: application of gis and remote sensing

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Journal of Geographical Sciences 2001年第3期11卷 261-270页

作者： ZHOU Hong-mei1, ZHOU Cheng-hu2. GE Wei-qiang1, DING Jin-cai3 (1. Shanghai Meteorological Institute, Shanghai 2.0030, china 2. state {2. laboratory of Resources and Environment Information System, Institute of Geographic Sciences and Natural Resources Shanghai Meteorological Institute Shanghai China state key {2. of Resources and Environment Information System Institute of Geographic Sciences and Natural Resources Research CAS Beijing China Meteorological Center Shanghai China

The urban thermal distribution characteristics and its variation are dynamically monitored and synthetically analyzed by using gis technology. The meteorological satellite data serve as main information source, assisted as auxiliary information sources by the landsat satellite TM data, land use thematic maps and meteorological observed data. A correlated pattern on the ground surface brightness temperatures and air temperatures has been studied and established with good performance of application.

关键词： remote sensing geographic information system urban thermal distribution application and study