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

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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 {2. 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 {2. for Remote Sensing of Environment and Digital Sites,beijing Normal University,beijing 100875,china state key {2. 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 ±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

Study on NDVI-T_s space by combining LAI and evapotranspiration

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Science china Earth Sciences 2006年第7期49卷 747-754页

作者： HAN Lijuan1,2.3, WANG Pengxin4, YANG Hua1,2.3, LIU Shaomin1,2.3 & WANG Jindi1,2.3 1. Research Center for Remote Sensing and gis, School of Geography, beijing Normal University, beijing 100875, china 2. state key laboratory of Remote Sensing Science, beijing 100875, china 3. beijing key laboratory for Remote Sensing of Environment and Digital Cities, beijing 100875, china 4. Department of Information Management, College of Information and Electronic engineering, china Agricultural University, beijing 100083, china Research Center for Remote Sensing and gis School of Geography Beijing Normal University Beijing China state key {2. of Remote Sensing Science Beijing China beijing key {2. for Remote Sensing of Environment and Digital Cities Beijing China Department of Information Management College of Information and Electronic Engineering China Agricultural University Beijing China

This paper focuses on interpreting the different spatial relationships between NDVI and Ts, a triangular or a trapezoid, and on analyzing transformation conditions, the physical and ecological meanings of the vegetation index-surface temperature space as well. Further, we use the Tempera-ture-Vegetation Dryness Index (TVDI) to explain the existent meaning of a triangular space after NDVI reaches its saturated state by employing the relationships between NDVI, LAI and evapotranspiration. The specific relations between NDVI and Ts are useful for describing, validating and updating land surface models.

关键词： NDVI, land surface temperature, evapotranspiration, leave area index.

High-accuracy topographical information extraction based on fusion of ASTER stereo-data and ICESat/GLAS data in Antarctica

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Science china Earth Sciences 2009年第5期52卷 714-722页

作者： E DongChen1,3,SHEN Qiang2.XU Ying1,3 & CHEN Gang4 1 chinese Antarctic Center of surveying and {2.,Wuhan University,Wuhan 430079,china 2.Institute of Seismology china Earthquake Administration,Wuhan 430071,china 3 key laboratory of Polar surveying and {2.,state Bureau of surveying and {2.,Wuhan University,Wuhan 430079,china 4 Department of Geography,University of Calgary,Calgary,Alberta T2. 1N4,Canada chinese Antarctic Center of surveying and {2. Wuhan University Wuhan China key laboratory of Polar {2. and mapping State Bureau of Surveying and Mapping Wuhan University Wuhan China Institute of Seismology china Earthquake Administration Wuhan China Department of Geography University of Calgary Calgary Canada

In order to better support Antarctic inland ice sheet expedition from Zhongshan Station to Dome A,the topographic data are *** present,although the entire Antarctic DEM provided by RAMP(Ra-darsat Antarctic mapping Project) was estimated at the highest horizontal(spatial) resolution of about 2.0 m,the real horizontal resolution of the DEM varies from place to place depending on the density and scale of the original source *** ice shelves and the inland ice sheet,the horizontal resolution is about 5 km;the vertical accuracy is estimated to be ±50 m in interior East Antarctic ice sheet and away from the mountain ***,more accurate topographic data are unavailable in *** order to meet the requirements of high-accuracy topographic information for further researches,this paper mainly addresses a fusion study of ASTER stereo pairs and ICESat/GLAS altimetry data for extraction of high-accuracy DEM in East Antarctica,based on the high horizontal resolution(15 m) of ASTER and vertical accuracy(13.8 cm) of ICESat/***,some altimetry data were selected as vertical control points to reduce errors of image correlation matching during the extraction of ASTER-based ***,ice sheet altimetry data derived from ICESat were used to generate DEM ranging from 75° to 81°S because existing ASTER data do not cover this area and high density of the coverage of ICESat altimetry ***,the DEM in coverage of the expedition route was *** analysis of result reveals that the DEM accuracy is improved *** absolute vertical accuracy of DEM is higher than 15 m in some cases and higher than 30 m for all the areas along the expedition route except from the 009-001 scene;the interior accuracy is higher than 15 m and higher than 7 m in some *** can meet the requirements of topographic map at 1:50000 scale,which is an economic and advantageous method to produce the topographic products.

关键词： DEM Antarctica Zhongshan Station Dome A ASTER ICESat GLAS

Fuzzy entropy image segmentation based on particle swarm optimization

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Progress in Natural Science:Materials International 2008年第9期18卷 1167-1171页

作者： Linyi Li a, Deren Li b, a School of Remote Sensing and Information engineering, Wuhan University, Wuhan 430079, china b {2. key laboratory of Information engineering in surveying, mapping and Remote Sensing, Wuhan University, Wuhan 430079, china School of Remote Sensing and Information engineering Wuhan University Wuhan 430079 China state key {2. of Information engineering in surveying Mapping and Remote Sensing Wuhan University Wuhan 430079 China

Particle swarm optimization is a stochastic global optimization algorithm that is based on swarm *** of its excellent performance, particle swarm optimization is introduced into fuzzy entropy image segmentation to select the optimal fuzzy parameter combination and fuzzy threshold *** this study, the particles in the swarm are constructed and the swarm search strategy is proposed to meet the needs of the segmentation *** fuzzy entropy image segmentation based on particle swarm opti-mization is implemented and the proposed method obtains satisfactory results in the segmentation *** with the exhaustive search method, particle swarm optimization can give the same optimal fuzzy parameter combination and fuzzy threshold while needing less search time in the segmentation experiments and also has good search stability in the repeated ***, fuzzy entropy image segmentation based on particle swarm optimization is an eficient and promising segmentation method.

关键词： Image segmentation Fuzzy entropy Particle swarm optimization Fuzzy parameter combinations Fuzzy threshold

Principle of small target detection for hyperspectral imagery

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Science china Earth Sciences 2007年第8期50卷 1225-1231页

作者： GENG XiuRui1,2.3 & ZHAO YongChao2.3,4 1 Research Center for Remote Sensing and gis, Department of Geography, beijing Normal University, beijing 100875, china 2.state key laboratory of Remote Sensing Science, chinese academy of Sciences, beijing 100101, china 3 Institute of Erectronics, chinese academy of Sciences, beijing 100080, china 4 Center for for Assessment and Monitoring of Forest and Environmental Resources and Division of Ecosystem Sciences University of California Berkeley, CA 9472.-3114, USA Research Center for Remote Sensing and gis Department of Geography Beijing Normal University Beijing China state key {2. of Remote Sensing Science Chinese Academy of Sciences Beijing China Institute of Erectronics Chinese Academy of Sciences Beijing China Center for for Assessment and Monitoring of Forest and Environmental Resources and Division of Ecosystem Sciences University of California Berkeley USA

This paper generalizes the progress of algorithms in small target detection for hyperspectral imaging, and finds that whitening the image is the key point of many methods in small target detection. An al-gorithm is presented to detect desired targets by converting large targets into small ones based on the weighted sample autocorrelation matrix.

关键词： hyperspectral whiten target detection

GRACE detection of the medium-to far-field coseismic gravity changes caused by the 2.04 Mw9.3 Sumatra-Andaman earthquake

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Earthquake Science 2012年第3期25卷 235-240页

作者： Jin Li1,2.3 and Wenbin Shen1,3,4, 1 Department of Geophysics, School of Geodesy and Geomatics, Wuhan University, Wuhan 430079, china 2.key {2. of Geodynamic Geodesy of chinese academy, Wuhan 430077, china 3 key {2. of Geospace Environment and Geodesy (Ministry of Education), Wuhan University, Wuhan 430079, china 4 state key {2. of Information {12. in surveying, mapping and Remote Sensing, Wuhan 430079, china Department of Geophysics School of Geodesy and Geomatics Wuhan University Wuhan 430079 China

Large earthquakes cause observable changes in the Earth’s gravity field, which have been detected by the Gravity Recovery and Climate Experiment (GRACE). Since most previous studies focus on the detection of near-field gravity effects, this study provides the results from the medium- to far-field gravity changes caused by the 2.04 Sumatra-Andaman earthquake that are recorded within GRACE monthly solutions. Utilizing a spherical-earth dislocation model we documented that large-scale signals predominate in the global field of the coseismic gravity changes caused by the earthquake. After removing the near-field effects, the coseismic gravity changes show a negative anomaly feature with an average magnitude of -0.18×10-8 m·s-2.in the region ranging ～40° from the epicenter, which is considered as the 'medium ffield' in this study. From the GRACE data released by Center for Space Research from August 2.02.to December 2.08, we retrieved the large-scale gravity changes smoothed with 3 000 km Gaussian ffilter. The results show that the coseismic gravity changes detected by GRACE in the medium field have an average of (-0.2.±0.06)×10-8 m·s-2. which agrees with the model prediction. The detection confirms that GRACE is sensitive to large-scale medium-field coseismic gravitational effects of mega earthquakes, and also validates the spherical-earth dislocation model in the medium field from the perspective of satellite gravimetry.

关键词： GRACE medium-to far-field coseismic gravity change 2.04 Sumatra-Andaman earthquake spherical-Earth dislocation model

Estimating surface evapotranspiration using combined MODIS and CBERS-02.data

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Science china(Technological Sciences) 2005年第S2期48卷 145-160页

作者： XIN Xiaozhou1,2. LIU Qinhuo1, TANG Yong1,3, TIAN Guoliang1, GU Xingfa1, LI Xiaowen1,2. ZHENG Hongsheng4 & CHEN Jiayi4 1. state key {2. of Remote Sensing Science, Institute of Remote Sensing Applications, chinese academy of Sciences, beijing 100101, china 2. Research Center for Remote Sensing and gis, Department of Geography, beijing Normal University, beijing 100875, china 3. Graduate University of chinese academy of Sciences, beijing 100039, china 4. Department of Atmospheric Physics, Peking University, beijing 100871, china state key {2. of Remote Sensing Science Institute of Remote Sensing Applications Chinese Academy of Sciences

Spatial scale error is one of the most serious problems in the estimates of land surface heat fluxes of sensible and latent from satellite-borne data such as MODIS 1km resolution reflectance and emissive data. One of the feasible and economic ways to decrease the spatial scale error is to use high resolution land use class data together with the MODIS data. CBERS-02.data were used to produce land use class of Baiyangdian area, Hebei Province, china in the autumn of 2.04. The area ratio of each class in MODIS pixel was calculated, and used to derive the heat fluxes of the mixed pixel. The results showed that the estimated heat fluxes of soil, sensible and latent have been changed remarkably after using the high resolution land class data. It could be concluded from the comparison between simulated and ground-measured fluxes as well as the theoretical analysis that high resolution land class data are useful to diminishing the scale error of heat fluxes estimated from low resolution satellite data.

关键词： surface evapotranspiration spatial scale error MODIS CBERS land class.

A new method for mining deformation monitoring with GPS-RTK

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中国有色金属学会会刊：英文版 2011年第S3期21卷 659-664页

作者： GAO Jing-xiang1, 2. LIU Chao2. WANG Jian1, 2. LI Zeng-ke2. MENG Xiang-chao2.1. key laboratory for Land Environment and Disaster Monitoring of {2. Bureau of surveying and mapping, china University of Mining and Technology, Xuzhou 2.1116, china 2. School of Environment and Spatial Informatics, china University of Mining and Technology, Xuzhou 2.1116, china key laboratory for Land Environment and Disaster Monitoring of {2. Bureau of surveying and mapping China University of Mining and Technology Xuzhou 221116 China School of Environment and Spatial Informatics China University of Mining and Technology Xuzhou 221116 China

Based on ranging intersection theory, a new method which is simple and easy to operate was proposed for data collection in the mine surface deformation monitoring with GPS-RTK centering rod measurements. It can fully eliminate the inevitable shaking error and the vertical deflection, and to some extent weaken the multipath effect on the estimates of coordinates in a relatively short period of time, using high-frequency observations. The results show that three-dimensional coordinates with a height accuracy better than 1 cm, horizontal accuracy better than 2.4 cm can be achieved through only 15-30 s continuous observation by 2. Hz high-frequency and effectively improve the measurement accuracy and efficiency of RTK, fully satisfying the high-speed and high-precision data acquisition in mine surface subsidence deformation monitoring.

关键词： GPS rover pole multipath delay deformation monitoring

A prototype auto-human support system for spatial analysis

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Progress in Natural Science:Materials International 2006年第9期16卷 954-966页

作者： LI Lianfa and WANG Jinfeng (state key {2. of Resources & Environmental Information System, Institute of Geographical Sciences & Natural Resources Research, chinese academy of Sciences, beijing 100101, china) state key {2. of Resources & Environmental Information System Institute of Geographical Sciences & Natural Resources Re- search Chinese Academy of Sciences Beijing 100101 China

Spatial analysis is a multidisciplinary field that involves multiple influential factors, variation and uncertainty, and modeling of geospatial data is a complex procedure affected by spatial context, mechanism and assumptions. In order to make spatial modeling easier, some scholars have suggested a lot of knowledge from exploratory data analysis (EDA), specification of the model, fitness and diagnosis of the model, to interpretation of the model. Also an amount of software has improved some functionalities of spatial analysis, e. g. EDA by the dynamic link (GeoDa) and robust statistical calculation (R). However, there are few programs for spatial analysis that can automatically deal with unstructured declarative issues and uncertainty in machine modeling using the domain knowledge. Under this context, this paper suggests a prototype support system for spatial analysis that can automatically use experience and knowledge from the experts to deal with complexity and uncertainty in modeling. The knowledge base component, as the major contribution of the system, in support of the expert system shell, codes and stores declarative modeling knowledge, e.g. spatial context, mechanisms and prior knowledge to deal with declarative issues during the modeling procedure. With the open architecture, the system integrates functionalities of other components, e.g. gis’ visualization, DBMS, and robust calculation in an interactive environment. An application case of spatial sampling, design and implementation of spatial modeling with such a system is demonstrated.

关键词： spatial analysis automatic support system modeling of spatial data artificial inference for modeling.