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

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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 {2. academy of sciences,Beijing 100875,china 2.epartment of geodesy and Geomatics,School of Land Science and Technology,china University of Geosciences,Beijing 100083,china State 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 China Department of geodesy and Geomatics School of Land Science and Technology China University of Geosciences Beijing 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

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西北太平洋中国沿海海面倾斜及其机理初探

海洋学报 2002年第5期24卷 19-25页

作者：张赤军中国科学院测量与地球物理研究所湖北武汉430077

海面倾斜与高程基准密切相关 ,它已经受到大地测量学界和海洋学界的重视 .进一步讨论了大地水准的测量精度 ,指出了大地 (几何 )水准与沿海验潮资料的不符是由于海面的倾斜 ;分析了海面倾斜的机理 ,其中包括海流、海水密度分布、气压、... 详细信息

海面倾斜与高程基准密切相关 ,它已经受到大地测量学界和海洋学界的重视 .进一步讨论了大地水准的测量精度 ,指出了大地 (几何 )水准与沿海验潮资料的不符是由于海面的倾斜 ;分析了海面倾斜的机理 ,其中包括海流、海水密度分布、气压、台风引起的破碎波等的作用 ;提出了用海水异常密度的三维分布计算大地水准面的扰动 ,实质上它反映了海面的倾斜 ,该量占大地水准测量结果的 73% 。

关键词：海面倾斜海流海水密度大地水准面大地测量气压台风破碎波

潜育化作用对水稻土磷素形态与供磷能力的影响

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土壤通报 2002年第4期33卷 275-277页

作者：陈世俭马毅杰中国科学院测量与地球物理研究所湖北武汉4430077 中国科学院南京土壤研究所江苏南京210008

本文对江汉平原四湖地区几个不同潜育度水稻土剖面的磷素状况及其有效性进行了研究 ,并用张守敬—Jakson无机磷分级法做无机磷分级。结果表明 ,土壤潜育化程度对土壤全磷没有明显的影响 ,对土壤磷素形态及其有效性有明显的影响。随着土... 详细信息

本文对江汉平原四湖地区几个不同潜育度水稻土剖面的磷素状况及其有效性进行了研究 ,并用张守敬—Jakson无机磷分级法做无机磷分级。结果表明 ,土壤潜育化程度对土壤全磷没有明显的影响 ,对土壤磷素形态及其有效性有明显的影响。随着土壤潜育化程度加重 ,无机磷中的O—P含量有增加趋势 ,其占土壤无机磷的百分数增大 ;土壤有机磷也随之增加 ;但有效磷含量减少。

关键词：潜育化作用水稻土磷素形态供磷能力无机磷分级

Seismic and geological evidence of hidden faults in the Yinpan Reservoir area based on a dense seismic array

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Science china Earth sciences 2024年第7期67卷 2401-2407页

作者： Guangyao YIN Huai zhang Liwen GONG Q ipeng BAI Yicun GUO Bing zhang Yaolin SHI Key Laboratoryof Earth System Numerical Modeling and Application(chinese academyof {2.) College of Earth and Planetary SciencesUniversity of Chinese Academy of SciencesBeijing 100049China Key Laboratory of Computational Geodynamics Chinese Academy of SciencesBeijing 100049China Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai) Zhuhai 519080China Beijing Yanshan Critical Zone National Field Scientific Observation and Research Station Beijing 101408China Chongqing Earthquake Agency Chongqing 401147 China Institute of Earthquake Forecasting China Earthquake AdministrationBeijing 100036China Hangzhou Applied Acoustics Research Institute Hangzhou 311100China State Key Laboratory of geodesy and Earths Dynamics Innovation Academy for Precision Measurement Science and TechnologyCASWuhan 430077China

*** November 2.,2.17,an M_(S)5.0 earthquake occurred in Wulong,Chongqing,china,resulting in tens of casualties and considerable economic ***,the epicenter of this earthquake was located in the transition zone from the... 详细信息

关键词： earthquake southeast seismic

Assessment of natural and anthropogenic impacts on terrestrial water storage in the Loess Plateau based on different types of GRACE/GRACE-FO solutions

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Journal of Mountain Science 2024年第7期21卷 2173-2192页

作者： zhang Cheng CHEN Peng ZHU Chengchang LU Jierui zhang Yuchen YANG Xinyue WU Mengyan College of Geomatics Xi'an University of Science and TechnologyXi'an 710054China State Key Laboratory of geodesy and Earth’s Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan 430077China

Changes in water resource storage are inevitable due to climate change and human activities,thus understanding alterations in water storage within a specific region is imperative for the planning and management of water *** from the Gravity Recovery and Climate Experiment(GRACE)satellite mission are extensively employed to analyze large-scale total terrestrial water storage anomalies(TWSA).In this study,we derived a more reliable TWSA using different types of GRACE gravity models,which served as the basis for evaluating spatial and temporal variations in total terrestrial water storage and its hydrological components(soil moisture and groundwater)across the Loess ***,we analyzed the impact of natural and anthropogenic influences on water storage in the Loess Plateau,categorizing them into primary and secondary influences,utilizing data on climate and human *** findings revealed a declining trend in the overall TWSA of the Loess Plateau,with a rate of decrease at-0.65±0.05 cm/yr from 2.03 to 2.2.(P2.09,and groundwater dominated the change of TWSA after ***,there was variability in the changes of TWSA in the Loess *** in-depth studies showed that soil moisture changes in the study area were primarily driven by evapotranspiration and temperature,with precipitation and vegetation cover status playing a secondary *** activities had a secondary effect on soil moisture in some *** change and agricultural development were major factors in altering groundwater storage in the study *** than that,groundwater was influenced by natural factors to a limited *** findings provided valuable insights for local governments to implement proactive water management policies.

关键词： GRACE Terrestrial water storage Human activity Loess Plateau

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信息抽取技术在LBS中的应用

四川大学学报（工程科学版） 2005年第1期37卷 116-120页

作者：张清军朱才连侯林山中国科学院测量与地球物理研究所湖北武汉430077

由于LBS系统的终端设备处理能力较低,显示屏幕较小,再加上无线数据网络带宽不足,因此无法浏览整个Web网页。采用信息抽取技术可以将用户感兴趣的信息提取出来,再发送给用户终端,有效地解决上述问题,信息抽取技术将是LBS系统中的一项重... 详细信息

由于LBS系统的终端设备处理能力较低,显示屏幕较小,再加上无线数据网络带宽不足,因此无法浏览整个Web网页。采用信息抽取技术可以将用户感兴趣的信息提取出来,再发送给用户终端,有效地解决上述问题,信息抽取技术将是LBS系统中的一项重要应用。提出了一种基于信息抽取的从HTML到WML的页面转换方法,首先标记少量的Web网页形成样本实例集,采用归纳算法生成信息抽取规则;其次应用抽取规则和模式匹配来处理结构和风格类似的Web页面;最后将抽取结果转换为WML页面。开发了原型系统,通过对实际数据源的抽取,验证了此方法的有效性。

关键词： LBS 信息抽取模式匹配页面转换

The Distribution of Surnames in Xiantao City through Isonymy

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Journal of geodesy and Geoinformation Science 2024年第2期7卷 52-65页

作者： zhang Jingjing ZHU Yan XIAO Hong College of chinese Language and Literature Wuhan UniversityWuhan 430072China College of Literature and Communication China Three Gorges UniversityYichang 443002China School of Foreign Languages China University of GeosciencesWuhan 430072China

The population migration in Hubei Province was frequent in history,accompanied by the migration of surnames,so it is important to study their population *** take Xiantao City as an example to explore the isonymic structure of small and medium-sized cities in *** surname distributions of 2.332. residents registered in 2.13 were analyzed in 5 towns and 105 villages of *** number of different surnames found was *** for surnames,theα-value reflects the influence of ethnic composition on the abundance of *** correlation between the isonymic distance and the geographic distance between villages was calculated and indicated that Euclidean distance was weakly correlated with the geographic distance(r=0.177±0.012.,and the isonymic distance increased with the geographical ***,the dendrogram and PCA built from the matrix of Euclidean distances between villages identified a main surname differentiation between the urban and rural areas.

关键词： Xiantao City surname distribution isonymy isolation by distance urban and rural areas

Probing signals of atmospheric gravity waves excited by the July 2.,2.2. M_(W)8.2.Alaska earthquake

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geodesy and Geodynamics 2024年第3期15卷 219-229页

作者： Geng zhang Jianqiao Xu Xiaodong Chen Heping Sun Lizhuo Gong State Key Laboratory of geodesy and Earth's Dynamics Innovation Academy for Precision Measurement Science and TechnologyChinese Academy of SciencesWuhan430077China University of chinese academy of {2. Beijing100049China

It is commonly believed that the atmosphere is decoupled from the solid ***,it is difficult for the seismic wave energy inside the Earth to propagate into the atmosphere,and atmospheric pressure wave signals excited by earthquakes are unlikely to exist in atmospheric *** increasing number of studies have shown that earthquakes,volcanoes,and tsunamis can perturb the Earth's atmosphere due to various coupling ***,the observations mainly focus on acoustic waves with periods of less than 10 min and inertial gravity waves with periods of greater than 1 *** are almost no clear observations of gravity waves that coincide with observations of low-frequency signals of the Earth's free oscillation frequency band within 1 *** paper investigates atmospheric gravity wave signals within1 h of surface-atmosphere observations using the periodogram method based on seismometer and microbarometer observations from the global seismic network before and after the July 2.,2.2. M_(w)8.2.Alaska earthquake in the United *** numerical results show that the atmospheric gravity wave signals with frequencies similar to those of the Earth's free oscillations _(0)S_(2. and _(0)T_(2. can be detected in the microbaro meter *** results con firm the existence of atmospheric gravity waves,indicating that the atmosphere and the solid Earth are not decoupled within this frequency band and that seismic wave energy excited by earthquakes can propagate from the interior of the Earth to the atmosphere and enhance the atmospheric gravity wave signals within 1 h.

关键词： Atmospheric gravity modes Atmospheric gravity waves Alaska earthquake Normal modes Coupling of solid earth and atmosphere

An improved GNSS ambiguity best integer equivariant estimation method with Laplacian distribution for urban low-cost RTK positioning

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Satellite Navigation 2024年第1期5卷 109-124页

作者： Ying Liu Wanke Liu Xiaohong zhang Yantao Liang Xianlu Tao Liye Ma School of geodesy and Geomatics Hubei Luojia LaboratoryWuhan University129 Luoyu RoadWuhan430079HubeiChina chinese Antarctic Center of Surveying and Mapping Wuhan University129 Luoyu RoadWuhan430079HubeiChina School of Instrument Science and Engineering Southeast UniversityNanjingJiangsuChina The 54 Research Institute of China Electronics Technology Group CorporationShijiazhuang050081HebeiChina State Key Laboratory of Satellite Navigation System and Equipment Technology Shijiazhuang050081HebeiChina

The integer least squares(ILS)estimation is commonly used for carrier phase ambiguity resolution(AR).More recently,the best integer equivariant(BIE)estimation has also attracted an attention for complex application scenarios,which exhibits higher reliability by a weighted fusion of integer ***,traditional BIE estimation with Gaussian distribution(GBIE)faces challenges in fully utilizing the advantages of BIE for urban low-cost positioning,mainly due to the presence of outliers and unmodeled *** this end,an improved BIE estimation method with Laplacian distribution(LBIE)is proposed,and several key issues are discussed,including the weight function of LBIE,determination of the candidates included based on the OIA test,and derivation of the variance of LBIE solutions for reliability *** results show that the proposed LBIE method has the positioning accuracy similar to the BIE using multivariate t-distribution(TBIE),and significantly outperforms the ILS-PAR and GBIE *** an urban expressway test with a Huawei Mate40 smartphone,the LBIE method has positioning errors of less than 0.5 m in three directions and obtains over 50%improvements compared to the ILS-PAR and GBIE *** an urban canyon test with a low-cost receiver STA8100 produced by STMicroelectronics,the positioning accuracy of LBIE in three directions is 0.112.m,0.107 m,and 0.2.2.m,respectively,with improvements of 17.6%,2..2.,and 2..1%compared to GBIE,and 2..3%,2..2.,and 30.6%compared to ***,its computational time increases by 30–40%compared to ILS-PAR and is approximately half of that using TBIE.

关键词： Ambiguity resolution Best integer equivariant estimation Laplacian distribution Urban environments Low-cost GNSS receivers Real-time kinematic