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Geometric active contour based approach for segmentation of high-resolution spaceborne SAR images

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Journal of Systems Engineering and Electronics 2015年第1期26卷 69-76页

作者： Shaoming Zhang Fang He Yunling Zhang Jianmei Wang Xiao Mei Tiantian Feng College of surveying Mapping and Geo-Informatics Tongji University Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences

Segmentation is the key step in auto-interpretation of high-resolution spaceborne synthetic aperture radar（SAR） images. A novel method is proposed based on integrating the geometric active contour（GAC） and the support vector machine（SVM）models. First, the images are segmented by using SVM and textural statistics. A likelihood measurement for every pixel is derived by using the initial segmentation. The Chan-Vese model then is modified by adding two items： the likelihood and the distance between the initial segmentation and the evolving contour. Experimental results using real SAR images demonstrate the good performance of the proposed method compared to several classic GAC models.

关键词： image segmentation synthetic aperture radar(SAR) imagery support vector machine(SVM) geometric active contour(GAC)

A high-level architecture for a Geomatics Informatization Technology System: the chinese case

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International Journal of Digital Earth 2011年第2期4卷 93-107页

作者： Jixian Zhang Weisen Li Liang Zhai chinese academy of surveying and mapping No.28 Lianhuachixi Rd.Haidian Dist.Beijing 100830China State Bureau of surveying and mapping No.28 Lianhuachixi Rd.Haidian Dist.Beijing 100830China

China will,as a component of‘Digital Earth,’establish a Geomatics Informatization Technology System(GITS)which is characterized by real-time acquisition,automatic processing,networking service,and socialized application with fundamental geographical *** basic composition of GITS is *** covers four layers and six *** four layers are data acquisition,processing,management,and application and *** six platforms are informatic geodetic datum,high-precision geo-spatial data acquisition,automatic geo-spatial data processing,grid-based geo-spatial information management,comprehensive geo-spatial information sharing and service,and geo-spatial information integration and *** informatic geodetic datum platform provides a carrier for all the four layers and a base for the other five *** high-precision geo-spatial data acquisition platform belongs to the acquisition *** automatic geo-spatial data processing platform belongs to the processing *** grid-based geo-spatial information management platform belongs to the management layer and is a bridge connecting geospatial data acquisition and spatial information sharing service and integrated *** comprehensive geo-spatial information sharing and service platform belongs to the application and service ***,this paper presents thoughts for constructing GITS.

关键词： Digital Earth geomatics geodetic datum data acquisition and processing information management and service

Spatiotemporal dynamics of population density in China using nighttime light and geographic weighted regression method

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International Journal of Digital Earth 2023年第1期16卷 2704-2723页

作者： Wei Guo Jinke Liu Xuesheng Zhao Wei Hou Yunxuan Zhao Yongxing Li Wenbin Sun Deqin Fan College of Geoscience and surveying Engineering China University of Mining and TechnologyBeijingPeople’s Republic of China chinese academy of surveying&mapping BeijingPeople’s Republic of China

The distribution and dynamic changes of regional or national population data with long time series are very important for regional planning,resource allocation,government decision-making,disaster assessment,ecological protection,and other sustainability ***,the existing population datasets such as LandScan and WorldPop all provide data from 2000 with limited time series,while GHS-POP only utilizes land use data with limited *** view of the limited remote sensing images of long time series,it is necessary to combine existing multi-source remote sensing data for population spatialization *** this research,we developed a nighttime light desaturation index(NTLDI).Through the cross-sensor calibration model based on an autoencoder convolutional neural network,the NTLDl was calibrated with the same period Visible Infrared Imaging Radiometer Suite Day/Night Band(VIRS-DNB)***,the geographically weighted regression method is used to determine the population density of China from 1990 to 2020 based on the long time series ***,the change characteristics and the driving factors of China's population spatial distribution are *** large-scale,long-term population spatialization results obtained in this study are of great significance in government planning and decision-making,disaster assessment,resource allocation,and other aspects.

关键词： Nighttime light Population density Geographically weighted regression Population spatialization Driving force analysis

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 mapping,Wuhan University,Wuhan 430079,China 2 Institute of Seismology China Earthquake Administration,Wuhan 430071,China 3 Key Laboratory of Polar surveying and mapping,State Bureau of surveying and mapping,Wuhan University,Wuhan 430079,China 4 Department of Geography,University of Calgary,Calgary,Alberta T2N 1N4,Canada chinese Antarctic Center of surveying and mapping Wuhan University Wuhan 430079 China Institute of Seismology China Earthquake Administration Wuhan 430071 China Key Laboratory of Polar surveying and mapping State Bureau of Surveying an

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 200 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

Prototype of space-borne LTT module and its ground tests

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Science China(Physics,Mechanics & Astronomy) 2008年第8期51卷 1179-1186页

作者： WANG YuanMing YANG FuMin HUANG PeiCheng ZHANG ZhongPing CHEN WanZhen Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Graduate University Chinese Academy of SciencesBeijing 100049China Xi’an Institute of surveying and mapping Xi’an 710054China

In order to develop the technique of Laser Time Transfer(LTT) ,Shanghai Astronomical Observatory has built a prototype of space-borne LTT module. The performance of the LTT module and the results of ground tests are discussed in the paper. The average precision of time difference between two rubidium clocks measured by laser pulses is 196 ps,and the uncertainty of measurement for the relative frequency differences is 1.2×10-13/2800 s.

关键词： Laser Time Transfer(LTT) clock difference time synchronization Satellite Laser Ranging(SLR)

A Spatialization-based Method for Checking and Updating Metadata

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Journal of China University of Mining and Technology 2005年第3期15卷 183-186页

作者： ZHAO Ren-liang WANG Dong-hua SHI Li-hong ZHANG Bei-fei SHANG Yao-ling WANG Zhong-xiang National Geomatics Center of China Beijing 100044 China chinese academy of surveying and mapping Beijing 100039 China

In this paper the application of spatialization technology on metadata quality check and updating was dis-cussed. A new method based on spatialization was proposed for checking and updating metadata to overcome the defi-ciency of text based methods with the powerful functions of spatial query and analysis provided by GIS software. Thismethod employs the technology of spatialization to transform metadata into a coordinate space and the functions ofspatial analysis in GIS to check and update spatial metadata in a visual environment. The basic principle and technicalflow of this method were explained in detail, and an example of implementation using ArcMap of GIS software wasillustrated with a metadata set of digital raster maps. The result shows the new method with the support of interactionof graph and text is much more intuitive and convenient than the ordinary text based method, and can fully utilize thefunctions of GIS spatial query and analysis with more accuracy and efficiency.

关键词： metadata data quality checking spatialization spatial analysis

Retrieval of snow depth on Antarctic sea ice from the FY-3D MWRI data

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Acta Oceanologica Sinica 2023年第12期42卷 105-117页

作者： Zhongnan Yan Xiaoping Pang Qing Ji Yizhuo Chen Chongxin Luo Pei Fan Zeyu Liang chinese Antarctic Center of surveying and mapping Wuhan UniversityWuhan 430079China Key Laboratory of Polar surveying and mapping Science Ministry of Natural ResourcesWuhan 430079China

The snow depth on sea ice is an extremely critical part of the *** and understanding changes of snow depth on Antarctic sea ice is beneficial for research on sea ice and global climate *** Microwave Radiation Imager(MWRI)sensor aboard the chinese FengYun-3D(FY-3D)satellite has great potential for obtaining information of the spatial and temporal distribution of snow depth on the sea *** comparing in-situ snow depth measurements during the 35th chinese Antarctic Research Expedition(CHINARE-35),we took advantage of the combination of multiple gradient ratio(GR(36V,10V)and GR(36V,18V))derived from the measured brightness temperature of FY-3D MWRI to estimate the snow *** method could simultaneously introduce the advantages of high and low GR in the snow depth retrieval model and perform well in both deep and shallow snow *** on this,we constructed a novel model to retrieve the FY-3D MWRI snow depth on Antarctic sea *** new model validated by the ship-based observational snow depth data from CHINARE-35 and the snow depth measured by snow buoys from the Alfred Wegener Institute(AWI)suggest that the model proposed in this study performs better than traditional models,with root mean square deviations(RMSDs)of 8.59 cm and 7.71 cm,respectively.A comparison with the snow depth measured from Operation IceBridge(OIB)project indicates that FY-3D MWRI snow depth was more accurate than the released snow depth product from the *** Snow and Ice Data Center(NSIDC)and the National Tibetan Plateau Data Center(NTPDC).The spatial distribution of the snow depth from FY-3D MWRI agrees basically with that from ICESat-2;this demonstrates its reliability for estimating Antarctic snow depth,and thus has great potential for understanding snow depth variations on Antarctic sea ice in the context of global climate change.

关键词： snow depth Antarctic sea ice passive microwave FY-3D

Daily sea ice concentration product based on brightness temperature data of FY-3D MWRI in the Arctic

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Big Earth Data 2022年第2期6卷 164-178页

作者： Ying Chen Xi Zhao Xiaoping Pang Qing Ji chinese Antarctic Center of surveying and mapping Wuhan UniversityWuhanChina

A daily sea ice concentration(SIC)product in the Arctic,derived from the brightness temperature(TB)data of the Microwave Radiation Imager(MWRI)sensor aboard on the FY-3D satellite,is described in this *** MWRI TB raw swath data were first processed into daily gridded data and then corrected using the Advanced Microwave Scanning Radiometer 2(AMSR2)*** ASI algorithm,which uses daily dynamic tie points,was adopted to calculate daily SIC at 12.5 km polar stereographic projection from January 2018 to June *** generated MWRI SIC product was compared with the AMSR2 SIC based on the ASI algorithm that uses fixed tie *** more detailed comparison,we then compared our MWRI SIC with the SIC from the Moderate Resolution Imaging Spectroradiometer(MODIS)*** mean bias between our MWRI SIC and AMSR2 SIC is 4.24%.The absolute values of biases between the daily MWRI SIC and MODIS SIC range from 0.14%to 10.76%,better than the MWRI SIC product based on the NT2 algorithm published by the chinese National Satellite Meteorological *** results show that our MWRI SIC product has a good quality and can be used as a basic dataset for sea ice extent *** dataset is available at http://***/10.11922/sciencedb.00137.

关键词： Sea ice concentration FY-3D MWRI brightness temperature Arctic

Geo-environment in the Sustainable Development of chinese Cities

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Geo-Spatial Information Science 2002年第4期5卷 1-4页

作者： CHEN Junyong chinese academy of Sciences Chinese Academy of Surveying and Mapping 16 North Taiping Road Beijing 100039 China

Urban geo_environment mainly concerns those regards in and around a city,such as the movement of earth crust and earth surface,conditions of hydrology,geology,geography and *** relevant studies on geo_disaster reduction and the influences resulted from human activities on the geo_environment are included as *** is stressed in the paper that geo_environmental protection and management are of significance to the sustainable development for chinese cities.

关键词： city sustainable development geo_environment geo_disaster reduction