检索结果-南通市图书馆

Synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data

在线全文

学校读者我要写书评

暂无评论

science china(Technological sciences) 2008年第S2期51卷 176-187页

作者： BAO YunFei1,2,CAO ChunXiang1,ZHANG Hao1,CHEN ErXue3,HE QiSheng1,2,HUANG HuaBing1,LI ZengYuan3,LI XiaoWen1,4 & gong peng1 1 state key laboratory of remote sensing science,jointly sponsored by the institute for remote sensing applications of chinese academy of sciences and beijing normal university,beijing 100101,china 2 Graduate university of the chinese academy of sciences,beijing 100049,china 3 institute of Forest Resource Information Technique,the chinese academy of Forestry,beijing 100091,china 4 Research Center for remote sensing and GIS,Department of Geography and beijing key laboratory for remote sensing of Environment and Digital Sites,beijing normal university,beijing 100875,china state key laboratory of remote sensing science jointly sponsored by the Institute for Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate university of the chinese academy of sciences Beijing China institute of Forest Resource Information Technique the Chinese Academy of Forestry Beijing China Research Center for remote sensing and GIS Department of Geography and Beijing Key Laboratory for Remote Sensing of Environment and Digital Sites Beijing Normal University Beijing China

We proposed a method to separate ground points and vegetation points from discrete return,small footprint airborne laser scanner data,called skewness change *** method,which makes use of intensity of laser scanner data,is especially applicable in steep,and forested *** does not take slope of forested area into account,while other algorithms consider the change of slope in steep forested *** ground points and vegetation points can be used to estimate digital terrain model(DTM) and fractional vegetation cover,respectively.A few vegetation points which were classified into the ground points were removed as noise before the generation of *** method was tested in a test area of 10000 square meters.A LiteMapper -5600 laser system was used and a flight was carried out over a ground of 700―800 *** this tested area,a total number of 1546 field measurement ground points were measured with a total station TOPCON GTS-602 and TOPCON GTS -7002 for validation of DTM and the mean error value is -18.5 cm and the RMSE(root mean square error) is ±20.9 cm.A data trap sizes of 4m in diameter from airborne laser scanner data was selected to compute vegetation fraction *** of fractional vegetation cover was carried out using 15 hemispherical photographs,which are georeferenced to centimeter accuracy by differential *** gap fraction was computed over a range of zenith angles 10° using the gap light analyzer(GLA) from each hemispherical *** R2 for the regression of fractional vegetation cover from these ALS data and the respective field measurements is *** this study presents a method for synchronous estimation of DTM and fractional vegetation cover in forested area from airborne LIDAR height and intensity data.

关键词： LIDAR intensity skewness synchronous DTM fractional vegetation cover

Change of surface cover greenness in china between 2000 and 2010

在线全文

学校读者我要写书评

暂无评论

chinese science Bulletin 2012年第22期57卷 2835-2845页

作者： liu shuang1,4& gong peng1,2,31state key laboratory of remote sensing science, jointly sponsored by institute of remote sensing applications of chinese academy of sciences,and beijing normal university, beijing 100101, china 2institute for Global Change Studies & Center for Earth System science, Tsinghua university, beijing 100084, china 3Department of Environmental science, Policy and Management, university of California, Berkeley, CA94720, USA 4Graduate university of chinese academy of sciences, beijing 100049, china state key laboratory of remote sensing science Jointly Sponsored by Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing China Graduate university of chinese academy of sciences Beijing China institute for Global Change Studies & Center for Earth System science Tsinghua University Beijing China Department of Environmental science Policy and Management University of California Berkeley USA

Surface greenness reflects the situation of vegetation *** index calculated from the Red and Near Infrared bands of remote sensing images,whose values indicate the level of photosynthetic activity,is monotonically related to surface greenness when vegetation canopy does not fully cover the background *** for desert regions,vegetation index is positively correlated with vegetation ***,vegetation index can be used to study the change in greenness of desert *** study collected MODIS normalized Difference Vegetation Index (NDVI) data from 2000 to 2010 and analyzed their change over china in this *** results showed that an increasing trend of NDVI occurred over 66.84% (OLS fitting) or 64.27% (LAD fitting) of china,indicating that china's greenness is increasing ***,desertification of china *** showing large increase in greenness are found in Shaanxi,Shanxi,Ningxia,Henan,Shandong,Qinghai,and Gansu while regions with large decrease in greenness are found in Northeast Inner Mongolia,South Tibet,Jiangsu,and *** of Qinghai,Gansu,Xinjiang and South Tibet could probably be driven by climate *** of greenness in Northeast Inner Mongolia was related to agricultural *** of greenness in Jiangsu and Shanghai was related to rapid *** factors did not exhibit obvious correspondence to the large increase in greenness in Shaanxi,Shanxi,Ningxia and Gansu,indicating that the changes might have been caused by human *** reduction of desert areas in china could probably have been caused by human management and protection at the national scale.

关键词：中国地表覆盖归一化植被指数植被覆盖度沙漠地区 NDVI 西藏南部气候因素

An efficient rendering method for large vector data on large terrain models

在线全文

学校读者我要写书评

暂无评论

science china(Information sciences) 2010年第6期53卷 1122-1129页

作者： YANG Ling1,ZHANG LiQiang1,KANG ZhiZhong2,XIAO ZhiQiang1,peng JunHuan2,ZHANG XingMing1 & liu liu11state key laboratory of remote sensing science,jointly sponsored by beijing normal university and the institute of remote sensing applications of chinese academy of sciences,beijing 100875,china 2Department of Geodesy and Geomatics,School of Land science and Technology,china university of Geosciences,beijing 100083,china state key laboratory of remote sensing science Beijing Normal University state key laboratory of remote sensing science Institute of Remote Sensing Applications of Chinese Academy of Sciences Department of Geodesy and Geomatics School of Land Science

This paper presents an efficient way to render large-scale vector maps on level-of-detail(LOD) digital elevation models(DEMs).By using the frame buffer and Voronoi diagram,we achieve a rapid simplification of large-scale vector maps while keeping their original topological *** the simplified maps,we establish level-of-detail vector map *** the detailed level,we use the stencil shadow volume approach to render the map accurately,and in the coarse level we use substitute techniques to render the map approximately yet more *** method proposed in this paper is universally applicable to rendering vector maps on various LOD terrain models,and the overlaying performance is independent of the complexity of underlying terrain *** use of the view frustum culling and sub-region index techniques,the impact of complexity of vector maps is reduced,and the rendering time is restricted to a certain ***,we can achieve seamless and rapid rendering of large-scale vector maps on LOD terrain surfaces.

关键词： large-scale vector maps LODs view-dependent visualization

A Spectral Index for Estimating Soil Salinity in the Yellow River Delta Region of china Using EO-1 Hyperion Data

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Pedosphere 2010年第3期20卷 378-388页

作者： WENG Yong-Ling gong peng ZHU Zhi-Liang Department of Surveying and Mapping Engineering College of Transportation Southeast University Nanjing 210096(China) state key laboratory of remote sensing science Institute of Remote Sensing Applications of the Chinese Academy ofSciences and Beijing Normal University Beijing 100101 (China) Department of Environment science Policy and Management University of California Berkeley CA 94720 (USA) EROS Data Center U.S. Geological Survey Sioux Falls SD 57198 (USA)

Soil salinization is one of the most common land degradation processes. In this study, spectral measurements of saline soil samples collected from the Yellow River Delta region of china were conducted in laboratory and hyperspectral data were acquired from an EO-1 Hyperion sensor to quantitatively map soil salinity in the region. A soil salinity spectral index (SSI) was constructed from continuum-removed reflectance (CR-reflectance) at 2052 and 2203 nm, to analyze the spectral absorption features of the salt-affected soils. There existed a strong correlation (r = 0.91) between the SSI and soil salt content (SSC). Then, a model for estimation of SSC with SSI was established using univariate regression and validation of the model yielded a root mean square error (RMSE) of 0.986 and an R2 of 0.873. The model was applied to a Hyperion reflectance image on a pixel-by-pixel basis and the resulting quantitative salinity map was validated successfully with RMSE = 1.921 and R2 = 0.627. These suggested that the satellite hyperspectral data had the potential for predicting SSC in a large area.

关键词： hyperspectral reflectance soil salt content spectral absorption features

Data error propagation in stacked bioclimatic envelope models

在线全文

学校读者我要写书评

暂无评论

Integrative Zoology 2024年第2期19卷 262-276页

作者： Xueyan LI Babak NAIMI peng gong Miguel B.ARAÚJO Guangdong Provincial key laboratory of remote sensing and Geographical Information System Guangdong Open Laboratory of Geospatial Information Technology and ApplicationGuangzhou Institute of GeographyGuangdong Academy of ScienceGuangzhouChina ‘Rui Nabeiro’Biodiversity Chair CHANGE-MED InstituteUniversity ofÉvoraÉvoraPortugal Department of Geography and Department of Earth sciences University of Hong KongHong KongChina Department of Biogeography and Global Change National Museum of Natural SciencesCSICMadridSpain

Stacking is the process of overlaying inferred species potential distributions for multiple species based on outputs of bioclimatic envelope models(BEMs).The approach can be used to investigate patterns and processes of species *** data limitations on individual species distributions are inevitable,but how do they affect inferences of patterns and processes of species richness?We investigate the influence of different data sources on estimated species richness gradients in *** fitted BEMs using species distributions data for 334 bird species obtained from(1)global range maps,(2)regional checklists,(3)museum records and surveys,and(4)citizen science data using presence-only(Mahalanobis distance),presence-background(MAXENT),and presence–absence(GAM and BRT)*** species predictions were stacked to generate species richness ***,we show that different data sources and BEMs can generate spatially varying gradients of species *** environmental predictors that best explained species distributions also differed between data *** using citizen-based data had the highest accuracy,whereas those using range data had the lowest *** richness patterns estimated by GAM and BRT models were robust to data *** multiple data sets exist for the same region and taxa,we advise that explicit treatments of uncertainty,such as sensitivity analyses of the input data,should be conducted during the process of modeling.

关键词： richness patterns species distribution stacked bioclimatic envelope models uncertainty

Visible and near infrared reflectance spectroscopy for measuring soil heavy metal content as a quick method

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Geochimica 2006年第S1期 225-226页

作者： Yunzhao WU1, Jun CHEN2, Junfeng JI2, peng gong1, Qilin LIAO3, Hongrui MA2 1 state key Lab of remote sensing science, institute of remote sensing applications, chinese academy of sciences, beijing 100101, china 2 Department of Earth science, Nanjing university, Nanjing 210093, china 3 Geological Survey of Jiangsu Province, Nanjing 210093, china

remote sensing and geographic information systems in the spatial temporal dynamics modeling of infectious diseases

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

science china(Life sciences) 2006年第6期49卷 573-582页

作者： gong peng 1,XU Bing 2 & LIANG Song 1、3 1. state key laboratory of remote sensing science,jointly sponsored by the institute of remote sensing applications,Chi-nese academy of sciences and beijing normal university,Box 9718,beijing 100101,china 2. Department of Geography,university of Utah,Salt Lake City,UT 84112,USA 3. School of Public Health,university of California,Berkeley,CA 94720,USA state key laboratory of remote sensing science Jointly Sponsored by the Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Box 9718 Beijing 100101 China Department of Geography University of Utah Salt Lake City UT 84112 USA state key laboratory of remote sensing science Jointly Sponsored by the Institute of Remote Sensing Applications Chinese Academy of Sciences and Beijing Normal University Box 9718 Beijing 100101 China School of Public Health University of CaliforniaBerkeleyCA 94720USA

Similar to species immigration or exotic species invasion,infectious disease transmis-sion is strengthened due to the globalization of human activities. Using schistosomiasis as an exam-ple,we propose a conceptual model simulating the spatio-temporal dynamics of infectious diseases. We base the model on the knowledge of the interrelationship among the source,media,and the hosts of the disease. With the endemics data of schistosomiasis in Xichang,china,we demonstrate that the conceptual model is feasible; we introduce how remote sensing and geographic information systems techniques can be used in support of spatio-temporal modeling; we compare the different effects caused to the entire population when selecting different groups of people for schistosomiasis control. Our work illustrates the importance of such a modeling tool in supporting spatial decisions. Our mod-eling method can be directly applied to such infectious diseases as the plague,lyme disease,and hemorrhagic fever with renal syndrome. The application of remote sensing and geographic informa-tion systems can shed light on the modeling of other infectious disease and invasive species studies.

关键词： spatio-temporal modeling, spatial connectivity, prevention and control of infectious diseases, biological invasion.

在线全文

学校读者我要写书评

暂无评论

扬州市区京杭大运河水污染可视化模拟研究

系统仿真学报 2009年第12期21卷 3653-3657,3661页

作者：徐丙立林珲龚建华臧永强黄明祥太空与地球信息科学研究所香港中文大学中国香港中国科学院遥感应用研究所遥感科学国家重点实验室北京100101

以京杭大运河扬州市区段为研究对象,根据其水文特征选定了一维和二维水质模型。研究了如何实现污染时空分布的可视化模拟。详细讲述了可视化模拟的几个关键技术,即基本框架、河流栅格数据提取与叠加显示、水质模型的数值化处理与集成、... 详细信息

以京杭大运河扬州市区段为研究对象,根据其水文特征选定了一维和二维水质模型。研究了如何实现污染时空分布的可视化模拟。详细讲述了可视化模拟的几个关键技术,即基本框架、河流栅格数据提取与叠加显示、水质模型的数值化处理与集成、多点排污计算与颜色匹配、污染曲线绘制及多时相历史污染再现。开发河流水污染可视化模拟系统,对扬州市区京杭大运河真实数据和假设数据分别模拟,效果良好。创新点在于将地理信息和专业的水污染模型无缝集成,并将数据、模型计算和结果表达集成在统一的实时可视化平台中。

关键词：河流水污染可视化模拟

中国北方13省土地利用景观格局变化分析(19891999)

在线全文

学校读者我要写书评

暂无评论

水土保持学报 2005年第5期19卷 143-146页

作者：李月臣宫鹏陈晋刘春霞何春阳环境演变与自然灾害教育部重点实验室北京师范大学资源学院北京100875 遥感科学国家重点实验室中国科学院遥感应用研究北京100101 重庆师范大学地理科学学院重庆400047

以北方13省为研究区,对该区1989～1999年的宏观土地利用景观格局变化进行了分析.结果表明:决定该区景观格局的主体要素类型为草地、难利用地和林地,其次为耕地.1989～1999年期间,区内景观异质性程度在逐渐提高, 土地利用向着多样化和均... 详细信息

以北方13省为研究区,对该区1989～1999年的宏观土地利用景观格局变化进行了分析.结果表明:决定该区景观格局的主体要素类型为草地、难利用地和林地,其次为耕地.1989～1999年期间,区内景观异质性程度在逐渐提高, 土地利用向着多样化和均匀化方向发展.景观空间格局变化特征是:耕地、林地和城镇用地破碎度最大;林地、草地和水域受到人类活动的严重干扰,斑块空间分布不断分散和破碎化,分离度和破碎度指标增加.草地的破碎度增加最为显著,严重影响该区农牧业的正常生产.景观要素之间的转化关系主要表现为林、草地和耕地之间的相互转化,以及草地退化为难利用地.表征了该区生态建设实践和生态破坏活动的相互作用以及草地的严重退化趋势,说明北方13省存在较为严重生态环境问题,急需解决.

关键词：景观格局变化土地利用北方13省