检索结果-南通市图书馆

Improving the initialization speed for long-range NRTK in network solution mode

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

Science China(Technological Sciences) 2020年第5期63卷 866-873页

作者： ZHANG Ming LÜJinHu BAI ZhengDong LIU Hui FAN ChengCheng Key Laboratory of Systems and Control Institute of Systems ScienceAcademy of Mathematics and Systems ScienceChinese Academy of SciencesBeijing 100190China School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China institute of Geomatics Tsinghua UniversityBeijing 100084China GNSS Research Center Wuhan UniversityWuhan 430079China guangxi zhuang autonomous region remote sensing information surveying and mapping institute Nanning 530023China

Initialization speed is one of the most important factors in network real time kinematic(NRTK)*** to the low correlation among the error sources of reference stations,it is difficult to fix reference station ambiguities of long-range NRTK *** traditional reference stations ambiguity resolution(AR)methods,baselines are usually solved independently which is called baseline solution(BS)mode in this *** the correlations among baselines are not taken into consideration in ambiguities estimation,the AR speed is ***,tens of minutes or longer time is required to *** propose a network solution(NS)mode approach,in which the correlations among the double-difference ambiguities(DDAs)as well as double-difference ionospheric delays(DDIDs)of different baselines are considered in estimating float ambiguity *** results show that the float ambiguity solutions obtained are more accurate with an improved ***,initialization speed is significantly increased by 18%in NS mode.

关键词： initialization speed network real time kinematic(NRTK) reference station ambiguity resolution(AR) network solution(NS)mode baseline solution(BS)mode

Influence of voxel size on forest canopy height estimates using full-waveform airborne LiDAR data

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2020年第3期7卷 392-403页

作者： Cheng Wang Shezhou Luo Xiaohuan Xi Sheng Nie Dan Ma Youju Huang College of Resources and Environment Fujian Agriculture and Forestry UniversityFuzhou350002China Key Laboratory of Digital Earth Science Institute of Remote Sensing and Digital EarthChinese Academy of SciencesBeijing100094China guangxi zhuang autonomous region institute of Natural Resources remote sensing Nanning530023China

Background: Forest canopy height is a key forest structure parameter. Precisely estimating forest canopy height is vital to improve forest management and ecological modelling. Compared with discrete-return LiDAR(Light Detection and Ranging), small-footprint full-waveform airborne LiDAR(FWL) techniques have the capability to acquire precise forest structural information. This research mainly focused on the influence of voxel size on forest canopy height ***: A range of voxel sizes(from 10.0 m to 40.0 m interval of 2 m) were tested to obtain estimation accuracies of forest canopy height with different voxel sizes. In this study, all the waveforms within a voxel size were aggregated into a voxel-based LiDAR waveform, and a range of waveform metrics were calculated using the voxelbased LiDAR waveforms. Then, we established estimation model of forest canopy height using the voxel-based waveform metrics through Random Forest(RF) regression *** and conclusions: The results showed the voxel-based method could reliably estimate forest canopy height using FWL data. In addition, the voxel sizes had an important influence on the estimation accuracies(R2 ranged from 0.625 to 0.832) of forest canopy height. However, the R2 values did not monotonically increase or decrease with the increase of voxel size in this study. The best estimation accuracy produced when the voxel size was 18 m(R2= 0.832, RMSE = 2.57 m, RMSE% = 20.6%). Compared with the lowest estimation accuracy, the R2 value had a significant improvement(33.1%) when using the optimal voxel size. Finally, through the optimal voxel size, we produced the forest canopy height distribution map for this study area using RF regression model. Our findings demonstrate that the optimal voxel size need to be determined for improving estimation accuracy of forest parameter using small-footprint FWL data.

关键词： Voxel size Airborne LiDAR Full-waveform Forests Canopy height

MDC-Net:a multi-directional constrained and prior assisted neural network for wood and leaf separation from terrestrial laser scanning

在线全文

学校读者我要写书评

暂无评论

International Journal of Digital Earth 2023年第1期16卷 1224-1245页

作者： Wenxia Dai Yiheng Jiang Wen Zeng Ruibo Chen Yongyang Xu Ningning Zhu Wen Xiao Zhen Dong Qingfeng Guan School of Geography and information Engineering China University of GeosciencesWuhanPeople’s Republic of China guangxi zhuang autonomous region institute of Natural Resources remote sensing NanningPeople’s Republic of China School of Computer Science China University of GeosciencesWuhanPeople’s Republic of China State Key Laboratory of information Engineering in surveying Mapping and Remote SensingWuhan UniversityWuhanPeople’s Republic of China National Engineering Research Center of Geographic information System China University of GeosciencesWuhanPeople’s Republic of China

Wood-leaf separation from terrestrial laser scanning(TLS)is a crucial prerequisite for quantifying many biophysical properties and understanding ecological *** this study,we propose a novel multi-directional collaborative convolutional neural network(MDC-Net)that takes the original 3D coordinates and useful features from prior knowledge(prior features)as input,and outputs the semantic labels of TLS point *** MDC-Net contains two key units:(1)a multi-directional neighborhood construction(MDNC)unit to obtain more representative neighbors and enable directionally aware feature encoding in the subsequent local feature extraction,to mitigate occlusion effects;(2)a collaborative feature encoding(CFE)unit is introduced to incorporate useful features from prior knowledge into the network through a collaborative cross coding to enhance the discrimination for thin structures(*** branches and leaf).The MDC-Net is evaluated onfive plots from forests in guangxi,China,with different branch architectures and leaf *** results showed that the MDC-Net achieved an OA of 0.973 and a mIoU of 0.821 and outperformed other related *** believe the MDC-Net would facilitate the usage of TLS in ecology studies for quantifying tree size and morphology and thus promote the development of relevant ecological applications.

关键词： Terrestrial laser scanning wood and leaf separation deep learning prior features

Effects of Enclosure on Grassland Ecological and Economic Benefits in Northern China

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

Chinese Geographical Science 2024年第1期34卷 67-78页

作者： HU Bo WEN Qingke XI Fengjiang LI Mengyao WANG Libing REN Yuejuan Aerospace information Research institute Chinese Academy of SciencesBeijing100094China University of Chinese Academy of Sciences Beijing100049China Inner Mongolia remote sensing Center Co. Ltd.Huhhot010000China Xilinhot the Maodeng pasture Xilinhot026000China China University of Mining and Technology Xuzhou221116China Shanxi Provincial Key Lab of Resources Environment and Disaster MonitoringCoal Geological Geophysical Exploration Surveying&Mapping Institute of Shanxi ProvinceJinzhong030600China

Grasslands in northern China serve the country as both an ecological barrier and a livestock production ***,installing enclosures has been becoming the major grassland restoration measure adopted by many local ***,the effects of restoration on both ecological and production benefits of grassland remain unclear for implemented grassland restoration ***,a representative rangeland in northern China,the Maodeng pasture in Inner Mongolia autonomous region was selected as the study area,and remote sensing monitoring analyses were carried out to quantify the ecological benefits and economic benefits from 2015 to *** results showed that:1) in terms of ecological benefits,the grassland area with a grassland coverage rate of more than 60% accounts for 32.3% of the regional area,and 86.4% of its grassland grew significantly better than the same period in2015,showing a significant improvement in grassland *** the average amount of carbon per unit area as the ecological benefit evaluation index,it increased by 27.1% to 32.48Tg C/yr from 2015 to 2021.2) In terms of economic benefits,both theoretical grass production and livestock carrying capacity increased from 2015 to *** to 2015,the theoretical grass production in 2021 increased by 24.8% to 71 900 *** livestock carrying capacity reached 52 100 sheep units in 2021,nearly 11 000 sheep units more than that in *** the study period,multiple economic indicators(on a per capita basis of permanent residents) for the pastoral area of Xilinhot City to which the Maodeng pasture belongs,have grown *** capita total income rose from 29 630 yuan(RMB) in2015 to 62 859 yuan(RMB) in *** on grassland resources to develop the pastoral ecology also broadens the potential economic development ***,the establishment of the reserve and the experiment of implanting an enclosure policy have had a significant and positive impact on Maodeng pasture’s develo

关键词： enclosure grassland ecological benefit economic benefit Maodeng pasture Inner Mongolia northern China

Hyperspectral Inversion Model of Available Potassium Content in Red Soil of Eucalyptus Plantation in Northern guangxi

在线全文

学校读者我要写书评

暂无评论

Meteorological and Environmental Research 2023年第2期14卷 61-65页

作者： Huibiao PAN Xiajie QIN Ronghui HU Zeyao ZHANG Jian TANG guangxi State-owned Huangmian Forest Farm Chongzuo 532200China guangxi zhuang autonomous region Forestry Research institute/guangxi Research and Development Center for New Forestry Fertilizer Nanning 530002China

Soil information is the basis of soil management and precise variable fertilization. The traditional method of obtaining soil information through chemical detection of laboratory has high cost and poor timeliness, which is difficult to meet the needs of digital forestry, soil monitoring and real-time management of nutrients. Taking red soil of Eucalyptus plantation in northern guangxi as the research object, the spectral data of samples with different soil available potassium contents were measured, and the spectral characteristics were analyzed, and the inversion model was established by using PLS method. The results showed that the spectral sensitive bands of available potassium content in red soil of the region mainly concentrated in 400-600, 1 450, 2 200 nm and so on. After the first derivative transformation, the redundant information in the original spectral data can be significantly reduced, and the correlation between spectral indexes and soil available potassium content can be improved. The full-band modeling results of R and FDR were better than those of significant bands. The optimal model was full-band-FDR-PLS, R2=0.862, and RMSE=2.718. The results of this study can be used for the application of near-earth remote sensing in guangxi, such as soil digital mapping, precise variable fertilization and real-time monitoring of soil available potassium.

关键词： Visible-near-infrared spectroscopy Near-earth remote sensing Linear model Plantation Soil information

Application of ALI, ASTER and World View-2 imagery for mineral prospecting – a case study in the Maizijing-Shulonggou area, Ningxia Hui autonomous region, China

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

Application of ALI, ASTER and World View-2 imagery for miner...

Responses of Spatial-temporal Variation of Karst Ecosystem Service Values to Landscape Pattern in Northwest of guangxi,China

第十五届全国数学地质与地学信息学术研讨会

作者：徐元进 Meng Pengyan Wu Hao 中国地质大学(武汉)资源学院数学地质遥感地质研究所 Hubei institute of Land surveying and mapping

To explore clues for gold prospecting in the Maizijing-Shulonggou area, Ningxia Hui autonomous region, China, this study extracted geological information related to fracture zones and hydrothermal alterations using ALI, ASTER, and World View-2 data, and subsequently, explored potential relationships between extracted geological characteristics and gold mineralization. The World View-2 image in the study area was used for fracture interpretation. The azimuth and density of linear fractures were investigated, and the results showed that linear fractures with NE direction were most common, identified gold mineralization spots except Au2 were all located in NE fracture zones, and all gold mineralization spots located in high fracture density areas where NE and NW fractures were the most common observations. Hydrothermal alteration minerals in exposed bedrocks were mapped using ALI and ASTER data. The spatial distribution of alteration minerals revealed regional specific alteration mineral in gold mineralization. In the northern Maizijing region, the composition of alteration mineral in the surrounding of Au1 was overwhelmed by quartz, while the alteration minerals in the surrounding of Au2-4 were dominated by limonite in the southern Shulonggou region. In the southern Shulonggou region, pyrite in buried quartz-pyritization belt and illitization-pyritization belt is likely to be the precursor of limonite. Heavy mineral assemblages were analyzed for native gold content, and the results suggested high native gold content in the illitization-pyritization belt, followed by quartz-pyritization belt, which was consistent with the strong association of limonite and gold mineralization.

关键词： remote sensing mineral prospecting fracture hydrothermal alteration gold mineralization Maizijing-Shulonggou area

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Geographical Science 2011年第4期21卷 446-453页

作者： ZHANG Mingyang WANG Kelin LIU Huiyu ZHANG Chunhua Key Laboratory for Agro-ecological Processes in Subtropical region Institute of Subtropical AgricultureChinese Academy of SciencesHunan 410125China Huanjiang Observation and Research Station for Karst Ecosystems Chinese Academy of SciencesHuanjiang 547100China College of Geography Science Nanjing Normal UniversityNanjing 210046China

The responses of spatiotemporal variation of ecosystem service values (ESVs) to landscape pattern from 1985 to 2005 in a typical Karst area of the northwest guangxi zhuang autonomous region,China,were examined us-ing remote sensing and geographic information system techniques in this *** total ecosystem service values de-clined significantly from 1985 to 1990,and then increased slowly from 1990 to 2005,almost equaled to the 1985 *** ecosystem service values tended to decline from the west to the east and from mountainous regions to peak-cluster depression areas in 1985,1990,2000 and 2005 *** the period from 1985 to 2005,the ecosystem ser-vice values have increased in the middle and eastern parts of the study *** pattern indices,such as total area,largest patch index,contagion,aggregative index,effective mesh and proportion of like adjacencies,are significantly correlated with ecosystem service *** suggests that ecosystem service values tend to increase with the growth of patch area and patch ***,there are negative correlations between ecosystem service values and landscape pattern indices,such as division index and patch *** indicates that ecosystem service values decrease with patch fragmentation and patch size *** ecosystem conditions in the typical Karst area have been improved because of the control measures of rocky *** is important to protect key landscape types,such as woodland,shrub and grassland,and to increase patch size and connectivity to avoid further ***,it is necessary to reduce disturbances to ensure the growth of ecosystem service values and to facilitate the sustainable development in this region.

关键词： landscape pattern ecosystem service values (ESVs) landscape indices Karst guangxi

Spatiotemporal changes of typical glaciers and their responses to climate change in Xinjiang,Northwest China

在线全文

学校读者我要写书评

暂无评论

Journal of Arid Land 2022年第5期14卷 502-520页

作者： HUANG Xiaoran BAO Anming GUO Hao MENG Fanhao ZHANG Pengfei ZHENG Guoxiong YU Tao QI Peng Vincent NZABARINDA DU Weibing State Key Laboratory of Desert and Oasis Ecology Xinjiang Institute of Ecology and GeographyChinese Academy of SciencesUrumqi 830011China University of Chinese Academy of Sciences Beijing 100049China Research Center for Ecology and Environment of Central Asia Chinese Academy of SciencesUrumqi 830011China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of Sciences and Higher Education CommissionIslamabad 45320Pakistan School of Geography and Tourism Qufu Normal UniversityRizhao 276800China College of Geographical Science Inner Mongolia Normal UniversityHohhot 010022China Xuchang University Xuchang 461000China Key Laboratory of Wetland Ecology and Environment Northeast Institute of Geography and AgroecologyChinese Academy of SciencesChangchun 130102China School of surveying and Land information Engineering Henan Polytechnic UniversityJiaozuo 454000China

Glaciers are highly sensitive to climate change and are undergoing significant changes in *** this study,we analyzed the spatiotemporal changes of typical glaciers and their responses to climate change in the period of 1990-2015 in 4 different mountainous sub-regions in Xinjiang Uygur autonomous region of Northwest China:the Bogda Peak and Karlik Mountain sub-regions in the Tianshan Mountains;the Yinsugaiti Glacier sub-region in the Karakorum Mountains;and the Youyi Peak sub-region in the Altay *** standardized snow cover index(NDSI)and correlation analysis were used to reveal the glacier area changes in the 4 sub-regions from 1990 to *** areas in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions in the period of 1990-2015 decreased by 57.7,369.1,369.1,and 170.4 km^(2),*** of glacier area center of gravity showed that quadrant changes of glacier areas in the 4 sub-regions moved towards the *** area on the south aspect of the Karlik Mountain sub-region was larger than that on the north aspect,while glacier areas on the north aspect of the other 3 sub-regions were larger than those on the south *** precipitation in the Karlik Mountain sub-region inhibited the retreat of glaciers to a certain ***,glacier area changes in the Bogda Peak and Youyi Peak sub-regions were not sensitive to the increased *** a seasonal time scale,glacier area changes in the Bogda Peak,Karlik Mountain,Yinsugaiti Glacier,and Youyi Peak sub-regions were mainly caused by accumulated temperature in the wet season;on an annual time scale,the correlation coefficient between glacier area and annual average temperature was-0.72 and passed the significance test at Pregions of Northwest China in the context of global warmin

关键词： glacier area change normalized snow cover index(NDSI) climate change remote sensing Altay Mountains Tianshan Mountains Karakorum Mountains