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Algebraic encoding scheme for aperture 3 hexagonal discrete global grid system

Science China Earth Sciences 2018年第2期61卷 215-227页

作者： BEN Jin LI YaLu zhou chenghu WANG Rui DU LingYu Institute of Surveying and Mapping Information Engineering University State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of Sciences College of Earth Science and Surveying Engineering China University of Mining and Technology (Beijing)

Discrete Global Grid Systems(DGGSs) are spatial references that use a hierarchical tessellation of cells to partition and address the entire globe. They provide an organizational structure that permits fast integration between multiple sources of large and variable geospatial data sufficient for visualization and analysis. Despite a significant body of research supporting hexagonal DGGSs as the superior choice, the application thereof has been hindered owing in part to the lack of a rational hierarchy with an efficient addressing system. This paper presents an algebraic model of encoding scheme for the Aperture 3 Hexagonal(A3H) DGGS. Firstly, the definition of a grid cell, which is composed of vertices, edges, and a center, is introduced to describe fundamental elements of grids. Secondly, by identifying the grid cell with its center, this paper proves that cell centers at different levels can be represented exactly using a mixed positional number system in the complex plane through the recursive geometric relationship between two successive levels, which reveals that grid cells are essentially special complex radix numbers. Thirdly, it is shown that through the recursive geometric relationship of successive odd or even levels, the mixed positional number system can also be applied to uniquely represent cell centers at different levels under specific constraint conditions, according to which the encoding scheme is designed. Finally, it is shown that by extending the scheme to 20 triangular faces of the regular icosahedron,multi-resolution grids on closed surfaces of the icosahedron are addressed perfectly. Contrast experiments show that the proposed encoding scheme has the advantages of theoretical rigor and high programming efficiency and that the efficiency of cross-face adjacent cell searching is 242.9 times that of a similar scheme. Moreover, the proposed complex radix number representation is an ideal formalized description tool for grid systems. The research i

关键词： Discrete Global Grid System Hexagon Positional number system Algebraic encoding

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The Generic Annular Bucket Histogram for Estimating the Selectivity of Spatial Selection and Spatial Join

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Geo-Spatial Information Science 2011年第4期14卷 262-273页

作者： Changxiu Cheng chenghu zhou Rongguo Chen State Key Laboratory of Resources and Environmental Information Systems Institute of Geographical Sciences and Natural Resources Research Chinese Academy of Sciences Beijing China

Selectivity estimation is crucial for query optimizers choosing an optimal spatial execution plan in a spatial database management *** paper presents an Annular Bucket spatial histogram(AB histogram)that can estimate the selectivity in finer spatial selection and spatial join operations even when the spatial query has more operators or more *** AB histogram is represented as a set of bucket-range,bucket-count value *** bucket-range often covers an annular region like a sin-gle-cell-sized photo *** bucket-count is the number of objects whose Minimum Bounding Rectangles(MBRs)fall between outer rectangle and inner rectangle of the *** that all MBRs in each a bucket distribute evenly,for every buck-et,we can obtain serial probabilities that satisfy a certain spatial selection or join conditions from the operations' semantics and the spatial relations between every bucket-range and query ***,according to some probability theories,spatial selection or join selectivity can be estimated by the every bucket-count and its *** paper also shows a way to generate an updated AB histogram from an original AB histogram and those *** tests show that the AB histogram not only supports the selectivity estimation of spatial selection or spatial join with "disjoint","intersect","within","contains",and "overlap" operators but also provides an approach to generate a reliable updated histogram whose spatial distribution is close to the distribution of ac-tual query result.

关键词： selectivity estimation AB histogram annular bucket spatial selection spatial join

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Comparision of Methods for Polarimetric SAR Tomography with Small Number of Baselines in Forested Areas

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Chinese Journal of Electronics 2019年第5期28卷 1073-1079页

作者： LIANG Lei zhou chenghu LI Xinwu GAO Xizhang WU Wenjin State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Key Laboratory of Digital Earth Sciences Institute of Remote Sensing and Digital Earth (RADI) Chinese Academy of Sciences

Synthetic aperture radar Tomography(TomoSAR) provides scene reflectivity estimation of vegetation along elevation coordinates. However, the more multi-baselines acquisition, the longer the time span of acquisition, which will result in serious temporal decorrelation in forested area. In this way, we expect to use as smaller number of baselines as possible to obtain high estimation accuracy in elevation direction. We thus investigate the performance of Polarimetric SAR tomography(Pol-TomoSAR) with small number of baselines in forested areas. The results show that compressive sensingbased Pol-TomoSAR has higher estimation accuracy in elevation direction than conventional Pol-TomoSAR with small number of baselines.

关键词： Synthetic aperture radar(SAR) Polarimetric SAR SAR tomography Compressive sensing

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Stability of patches of oasis landscape in arid areas:A case study of Sangong River Watershed,Xinjiang,China

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Chinese Science Bulletin 2006年第A1期51卷 92-100页

作者： LUO Geping zhou chenghu CHEN Xi Xinjiang Institute of Ecology and Geography Chinese Academy of Sciences Urumqi 830011 China Institute of Geographical Science and Resources Research Chinese Academy of Sciences Beijing 100101 China

绿洲的稳定性是在进化的过程和在干旱区域的绿洲的管理的关键科学问题之一。绿洲和它的表示的稳定性在不同规模也是不同的。这篇论文在 Tianshan 山的 Sangong 河分水岭与案例研究在风景补丁规模处理绿洲的稳定性。我们采用了 ther 激... 详细信息

绿洲的稳定性是在进化的过程和在干旱区域的绿洲的管理的关键科学问题之一。绿洲和它的表示的稳定性在不同规模也是不同的。这篇论文在 Tianshan 山的 Sangong 河分水岭与案例研究在风景补丁规模处理绿洲的稳定性。我们采用了 ther 激动地表达感情到进程 ther 的察觉到的、地理信息系统和数学统计方法激动地表达感情在 1978， 1987 和 1998 察觉到三个时期的图象，并且为在风景补丁规模代表绿洲稳定性提出途径。绿洲补丁的风景控制能力是动态风景变化的一种自然驱动力。在有它在它和另外的补丁之间的区域和形状复杂性和对比的风景变化增加以后的某个补丁类型的控制能力，和有它在它和另外的补丁之间的空间距离的还原剂。有最强壮的控制能力的补丁类型应该是风景的矩阵。绿洲风景补丁的变换源于自然、人为的驱动力，特别地人为的驱动力。变换比例越高，越多降低补丁类型的稳定性并且人为的骚乱越更强壮。有在在 1987 的 Sangong 河分水岭的最强壮的网控制能力的补丁类型是荒芜的草地，它是风景的矩阵；但是风景的矩阵在 1987 和 1998 被变成了灌溉陆地。绿洲风景进化上的风景补丁的控制能力逐渐地在程度也逐渐地减少了的 Sangong 河分水岭，和变化与时间减少了。这表明在风景补丁类型之中的相互作用通常通常趋于到还原剂，和绿洲风景补丁的自然稳定性趋于增加。然而，在风景补丁之中的变换由于集中的人的活动的增加更经常发生，它可能在绿洲风景引起环境资源补丁的更低的稳定性和介绍补丁的更高的稳定性。

关键词：稳定性景观保护绿洲 GIS 遥感 NDVI

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Spatio-temporal patterns of temperature extremes and their response to atmospheric circulation factors in China from 1961 to 2020

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Journal of Geographical Sciences 2024年第10期34卷 1883-1903页

作者： LUO Yuanbo zhou Yuke zhou chenghu State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Ecosystem Network Observation and Modeling Institute of Geographic Sciences and Natural Resources ResearchCAsBeijing 100101China

Changes in surface temperature extremes have become a global *** on the daily lowest temperature(TN)and daily highest temperature(TX)data from 2138weather stations in China from 1961 to 2020,we calculated 14 extreme temperature indices to analyze the characteristics of extreme temperature *** widespread changes observed in all extreme temperature indices suggest that China experienced significant warming during this ***,the cold extreme indices,such as cold nights,cold days,frost days,icing days,and the cold spell duration index,decreased significantly by-6.64,-2.67,-2.96,-0.97,and-1.01 days/decade,*** contrast,we observed significant increases in warm extreme *** number of warm nights,warm days,summer days,tropical nights,and warm spell duration index increased by 8.44,5.18,2.81,2.50,and 1.66d/decade,*** addition,the lowest TN,highest TN,lowest TX,and highest TX over the entire period rose by 0.47,0.22,0.26,and 0.16℃/decade,***,using Pearson's correlation and wavelet coherence analyses,this study identified a strong association between extreme temperature indices and atmospheric circulation factors,with varying correlation strengths and resonance periods across different time-frequency domains.

关键词： temperature changes global warming atmospheric circulation wavelet coherence analysis China

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Tracking the evolution processes and behaviors of mesoscale eddies in the South China Sea：a global nearest neighbor filter approach

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Acta Oceanologica Sinica 2017年第11期36卷 27-37页

作者： YI Jiawei DU Yunyan WANG Dongxiao zhou chenghu State Key Laboratory of Resources and Environmental Information System Institute of Geographic Science and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China University of Chinese Academy of Sciences Beijing 100049 China State Key Laboratory of Tropical Oceanography (LTO) South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China

The eddy tracking approach is developed using the global nearest neighbor filter（GNNF） to investigate the evolution processes and behaviors of mesoscale eddies in the South China Sea（SCS）. Combining the Kalman filter and optimal data association technologies, the GNNF algorithm is able to reduce pairing errors to 0.2% in tracking synthetic eddy tracks, outperforming other existing methods. A total of 4 913 eddy tracks that last more than a week are obtained by the GNNF during 1993–2012. The analysis of a growth and a decay based on 3 445 simple eddy tracks show that eddy radius, amplitude, and vorticity smoothly increase during the first half of lifetime and decline during the second half following a parabola opening downwards. The genesis of eddies mainly clusters northwest and southwest of Luzon Island whereas the dissipations concentrate the Xisha Islands where the underwater bay traps and terminates eddies. West of the Luzon Strait, northwest of Luzon Island, and southeast of Vietnam are regions where eddy splits and mergers are frequently observed. Short disappearances mainly distribute in the first two regions. Moreover, eddy splits generally result in a decrease of the radius and the amplitude whereas eddy mergers induce growing up. Eddy intensity and vorticity, on the contrary, are strengthened in the eddy splits and diminished in mergers.

关键词： mesoscale ocean eddies eddy tracking eddy split eddy merger South China Sea

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Spatio-temporal evolution and influencing factors of urban green development efficiency in China

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Journal of Geographical Sciences 2020年第5期30卷 724-742页

作者： zhou Liang zhou chenghu CHE Lei WANG Bao Faculty of Geomatics Lanzhou Jiaotong UniversityLanzhou 730070China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchCASBeijing 100101China School of Architecture and Urban Planning Nanjing UniversityNanjing 210093China Northwest Institute of Eco-Environment and Resources CASLanzhou 730000China

To resolve conflicts between development and the preservation of the natural environment,enable economic transformation,and achieve the global sustainable development goals(SDGs),green development(GD)is gradually becoming a major strategy in the construction of an ecological civilization and the ideal of building a"beautiful China",alongside the transformation and reconstruction of the global *** on a combination of the concept and implications of GD,we first used the Slacks Based Model with undesirable outputs(SBM-Undesirable),the Theil index,and the spatial Markov chain to measure the spatial patterns,regional differences,and spatio-temporal evolution of urban green development efficiency(UGDE)in China from 2005 to ***,by coupling natural and human factors,the mechanism influencing UGDE was quantitatively investigated under the framework of the human-environment *** results showed that:(1)from 2005 to 2015,the UGDE increased from 0.475 to 0.523,i.e.,an overall increase of 10%.In terms of temporal variation,there was a staged increase,with its evolution having the characteristics of a"W-shaped"pattern.(2)The regional differences in UGDE followed a pattern of eastern>central>*** different types of urban agglomeration,the UGDE had inverted pyramid cluster growth characteristics that followed a pattern of"national level>regional level>local level",forming a stable hierarchical scale structure of"super cities>mega cities>big cities>medium cities>small cities".(3)UGDE in China has developed with significant spatial agglomeration ***-efficiency type cities have positive spillover effects,while low-efficiency cities have negative *** types of urban evolution processes have a path dependence,and a spatial club convergence phenomenon exists,in which areas with high UGDE are concentrated and drive low UGDE elsewhere.(4)Under the framework of regional human-environment interaction,the degree of human and soc

关键词： green development efficiency green city green economy spatial scale sustainable development goals(SDGs)

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Enhanced piecewise regression based on deterministic annealing

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Science in China(Series F) 2008年第8期51卷 1025-1038页

作者： ZHANG JiangShe YANG YuQian CHEN XiaoWen zhou chenghu Institute for Information and System Sciences Faculty of Sciences Xi'an Jiaotong University Xi'an 710049 China State Key Laboratory of Resources & Environmental Information System Institute of Geography Chinese Academy of Sciences Beijing 100101 China

Regression is one of the important problems in statistical learning theory. This paper proves the global convergence of the piecewise regression algorithm based on deterministic annealing and continuity of global minimum of free energy w.r.t temperature, and derives a new simplified formula to compute the initial critical temperature. A new enhanced plecewise regression algorithm by using ＂migration of prototypes＂ is proposed to eliminate ＂empty cell＂ in the annealing process. Numerical experiments on several benchmark datasets show that the new algorithm can remove redundancy and improve generalization of the piecewise regression model.

关键词： statistical regression piecewise regression deterministic annealing generalization

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Climate effects on an inland alpine lake in Xinjiang, China over the past 40 years

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Journal of Arid Land 2013年第2期5卷 188-198页

作者： HuiXia CHAI WeiMing CHENG chenghu zhou ShangMin ZHAO HaiJiang LIU State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Department of Surveying Mapping College of Mining Technology Taiyuan University of Technology China National Environmental Monitoring Center

Inland lakes are important water resources in arid and semiarid regions. Understanding climate effects on these lakes is critical to accurately evaluate the dynamic changes of water resources. This study focused on the changes in Sayram Lake of Xinjiang, China, and addressed the effects of climate fluctuations on the inland lake based on long-term sequenced remote sensing images and meteorological data from the past 40 years. A geo- graphic information system （GIS） method was used to obtain the hypsometry of the basin area of Sayram Lake, and estimation methods for evaporation from rising temperature and water levels from increasing precipitation were proposed. Results showed that：（1）Areal values of Sayram Lake have increased over the past 40 years. （2） Both temperature and precipitation have increased with average increases of more than 1.8~C and 82 mm, respectively. Variation of the water levels in the lake was consistent with local climate changes, and the areal values show linear relationships with local temperature and precipitation data. （3） According to the hypsometry data of the basin area, the estimated lake water levels increased by 2.8 m, and the water volume increased by 12.9×108 m3 over the past 40 years. The increasing area of Sayram Lake correlated with local and regional climatic changes because it is hardly affected by human activities.

关键词： Sayram Lake climate change water body extraction areal variation inland alpine lake

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Scale effects of the continental coastline of China

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Journal of Geographical Sciences 2011年第6期21卷 1101-1111页

作者： SU Fenzhen GAO Yi zhou chenghu YANG Xiaomei FEI Xianyun LREIS Institute of Geographic Sciences and Natural Resources Research CAS Beijing 100101 China Yantai Institute of Coastal Zone Research CAS Yantai 264003 Shandong China Graduate University of Chinese Academy of Sciences Beijing 100049 China School of Geodesy ＆ Geomatics Engineering Huaihai Institute of Technology Lianyungang 222005Jiangsu China Jiangsu Marine Resources Development Research Institute Lianyungang 222005 Jiangsu China

Spatial scale is a fundamental problem in Geography. Scale effect caused by fractal characteristic of coastline becomes a common focus of coastal zone managers and researchers. In this study, based on DEM and remote sensing images, multi-scale continental coastlines of China were extracted and the fractal characteristic was analyzed. The results are shown as follows. （1） The continental coastline of China fits the fractal model, and the fractal dimension is 1.195. （2） The scale significant differences according to uplift effects with fractal dimensions of coastline have and subsidence segments along the continental coastlines of China. （3） The fractal dimension of coastline has significant spatial heterogeneity according to the coastline types. The fractal dimension of sandy coastline located in Luanhe River plain is 1.109. The dimension of muddy coastline located in northern Jiangsu Plain is 1.059, while that of rocky coastline along southeastern Fujian is 1.293. （4） The length of rocky coastline is affected by scale more than that of muddy and sandy coastline. Since coastline is the conjunction of sea, land and air surface, the study of coastline scale effect is one of the scientific bases for the researches on air-sea-land interaction in multi-scales.

关键词： scale effect fractal dimension coastline uplift segment subsidence segment coastline type

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