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 {2.) 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 {2. sensing science jointly sponsored by the Institute for Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China Graduate university of the chinese {2. of sciences Beijing 100049 China institute of Forest Resource Information Technique the Chinese Academy of Forestry Beijing 100091 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 100875 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 ±2..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 2.00 and 2.10

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 {2. 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 {2. 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 {2.ized Difference Vegetation Index (NDVI) data from 2.00 to 2.10 and analyzed their change over china in this *** results showed that an increasing trend of NDVI occurred over 66.84% (OLS fitting) or 64.2.% (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 {2.) 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 1. state key Laboratory of {2. sensing science Jointly Sponsored by Beijing Normal University and the Institute of Remote Sensing Applications of Chinese Academy of Sciences Beijing 100875 China2. Department of Geodesy and Geomatics School of Land Science and Technology China University of Geosciences Beijing 100083 China

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 {2. 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 2.52.and 2.03 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 = 1.92. and R2.= 0.62.. 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

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

在线全文

学校读者我要写书评

暂无评论

science china(Life {2.) 2006年第6期49卷 573-582页

作者： gong peng 1,XU Bing 2.& LIANG Song 1、3 1. {2. key Laboratory of remote sensing science,jointly sponsored by the institute of remote sensing {12.,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 9472.,USA 1. state key Laboratory of {2. sensing science Jointly Sponsored by the Institute of Remote Sensing Applications Chinese 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

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 {2. 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 {2. 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

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

在线全文

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 {2. key Lab of remote sensing science, institute of remote sensing applications, chinese {12. of sciences, beijing 100101, china 2.Department of Earth science, Nanjing university, Nanjing 2.0093, china 3 Geological Survey of Jiangsu Province, Nanjing 2.0093, china

Annual 30-m land use/land cover maps of china for 1980–2.15 from the integration of AVHRR, MODIS and Landsat data using the BFAST algorithm

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

中国科学：地球科学英文版 2020年第9期63卷 1390-1407页

作者： Yidi XU Le YU Dailiang peng Jiyao ZHAO Yuqi CHENG Xiaoxuan liu Wei LI Ran MENG Xinliang XU peng gong Ministry of Education key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing 100084China Ministry of Education Ecological Field Station for East Asian Migratory Birds Beijing 100084China key Laboratory of Digital Earth science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijing 100094China College of Natural Resources and Environment Huazhong Agricultural UniversityWuhan 430070China state key Laboratory of Resources and Environmental Information Systems Institute of Geographical Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China

Annual land use land cover(LULC)change information at medium spatial resolution(*** 30 m)is required in numerous subjects,such as biophysical modelling,land management and global change *** LULC information,however,is usually not available at continental or national scale due to reasons such as insufficient remote sensing data coverage or lack of computational *** we integrate high temporal resolution and coarse spatial resolution satellite images(i.e.,Moderate Resolution Imaging Spectroradiometer(MODIS)and Global Inventory Modelling and Mapping Studies(GIMMS){2.ized difference vegetation index(NDVI))with high spatial resolution datasets(china’s Land-Use/cover Datasets(CLUDs)derived from 30-meter Landsat TM/ETM+/OLI)to generate reliable annual nominal 30 m LULC maps for the whole of china between 1980 and *** also test the performance of a statistical based change detection algorithm(Breaks for Additive Seasonal and Trend),originally designed for tracking forest change,in classifying all-type LULC *** a result,a nominal 30 m annual land use/land cover datasets(CLUD-A)from 1980 to 2.15 was developed for the whole *** mapping results were assessed with a change sample dataset,a regional annual validation sample set and a three-year china sample *** the detected change years,75.61%matched the exact time of conversion within±1 *** mapping results provided a detail process of urbanization,deforestation,afforestation,water and cropland dynamics over the past 36 *** consistent characterization of land change dynamics for china can be further used in scientific research and to support land management for policy-makers.

关键词： Land use land cover(LULC) Breaks for Additive Seasonal and Trend(BFAST) Change detection Annual china

Automatic extraction of floating ice at Antarctic continental margin from remotely sensed imagery using object-based segmentation

在线全文

学校读者我要写书评

暂无评论

science china Earth {2. 2012年第1期55卷 622-632页

作者： ZHAO ZiYing liu Zhen gong {2. College of Global Change and Earth System Beijing Normal UniversityBeijing 100875China Center of Information & Network Technology Beijing Normal UniversityBeijing 100875China state key Laboratory of {2. sensing science jointly sponsored by the Institute of Remote Sensing ApplicationsChinese Academy of Sciences and Beijing Normal UniversityBeijing 100101China

Information of Antarctic iceberg and sea ice are valuable to Antarctic ice melting patterns studies which are helpful to understand climate conditions and general trends of our *** paper presents an automatic floating ice extraction method based on image segmentation technology using region *** effectively solves the over-segmentation and under-segmentation problems by merging the gray,contour,location and other information of each ice-object.A pixel-based extraction method is proposed to extract the small ices within 5 *** TM data,chinese environment disaster satellite HJ1B data,and MODIS 1B data used to detect Floating ice at Antarctic continental margin *** results showed that the extraction accuracies of the three kinds of data were all higher than 81 percent,while the accuracies of both TM data and HJ1B data were higher than 90%.Object-based information extraction methods can not only obtain the total area and number of floating ice objects in the whole region,but also provide precise details of single objects,including area,perimeter,contour,average brightness.

关键词： Antarctic ice extraction image segmentation object-oriented

同方期刊数据库