顾及拓扑面向实体的三维矢量数据模型   总被引：7，自引：1，他引：6  

郑坤  刘修国  吴信才  杨慧 《吉林大学学报(地球科学版)》2006,36(3):474-479

拓扑关系数据模型和面向实体的数据模型是两种典型的三维矢量数据模型。拓扑关系数据模型在表达复杂的地理实体的局部更新等方面存在一定的困难,而面向实体的数据模型存在拓扑关系处理复杂,存贮量大等缺点。针对这两个模型的优缺点,设计一个顾及拓扑面向实体的三维矢量数据模型,这是一种综合面向实体和拓扑关系的混合数据模型。这种模型具备了面向对象以及拓扑关系模型的优点,解决了地上三维景观、TIN和城市三维地质等应用对数据模型的要求。  相似文献   

带多个空洞的面对象间拓扑关系的层次组合模型     

谢俊平  杨敏华 《测绘学院学报》2011,(2)

空间拓扑关系描述是空间关系的主要内容,是与人类的认知概念一致的,在空间数据查询与挖掘等方面有重要应用。很多学者研究了不带空洞的面对象间的拓扑关系,但对于带空洞的面对象间的拓扑关系研究甚少。首先回顾了现有模型,并指出了各模型的优缺点,然后根据简单面对象的8种基本空间拓扑关系,对带多个空洞的面对象的拓扑关系进行了层次组合分析,提出了一种能描述带多个空洞的复杂面对象间的拓扑关系的层次组合模型。该模型能描述带多个空洞的复杂面对象间的所有拓扑关系,而且不因面对象中空洞的编号顺序不同导致模型所描述的结果不同,同时也弥补了4-4ID模型只能描述带一个空洞的面对象的不足。  相似文献   

三维散乱点云的Voronoi拓扑近邻点集查询算法     

孙殿柱  刘健  李延瑞  孙永伟 《武汉大学学报(信息科学版)》2011,(1):86-91

提出一种三维散乱点云的Voronoi拓扑近邻点集查询算法,该算法改进R*-tree建立三维散乱点云的空间索引结构,采用动态扩展空心球算法获取样点的k近邻点集,通过偏心扩展和自适应扩展获取样点拓扑近邻参考数据,生成该局部点集的Voronoi图,查询样点Voronoi邻域获取样点拓扑近邻点集。通过算法时间复杂度分析及相关实验,证明该算法可快速、准确地获取任意复杂散乱点云的Voronoi拓扑近邻点集。  相似文献   

空间实体关联规则提取技术研究     

王海涛  刘海砚 《测绘与空间地理信息》2011,34(1):5-9

总结了空间关联规则的定义及表达方法,针对传统关联规则提取方法的不足,根据提取的关联性指标不同,提出了基于空间拓扑关系提取法、基于空间距离、基于空间方向关系提取法和基于属性相似性提取法四种空间关联规则提取方法.设计了空间关联规则提取的技术流程,通过实例验证了方法的有效性,最后探讨了今后研究的方向.  相似文献   

Hα Surges Initiated by Newly-emerging Satellite Magnetic Fields     

WANG Jun-feng  ZHOU Tuan-hui  JI Hai-sheng 《Chinese Astronomy and Astrophysics》2014

On July 22, 2011 and in the active region NOAA 11259 there ap- peared the event of the ejection of solar atmospheric Hα surges. According to the full-disc Hα observations of the Big Bear Solar Observatory in United States, three consecutive surges at one and the same place in the north of the main spot of the active region were discovered. The trajectories of these three surges exhib- ited the ?gure of straight lines, and their integral con?guration is like an inverted Eiffel Tower. The ?rst two surges are quite similar, and in each of them there appeared two bright points in the northern part of the main spot. After several minutes, the surges appeared in the midst of bright points. When the bright- ness of the bright points attained the maximum value, the surges spouted out from the midst of bright points. And after reaching the maximum altitude, they quickly vanished. Before the ejection of the third surge took place, no bright points appeared. Besides, its maximal altitude is merely one half of that of the ?rst two surges. Via a comparison with the SDO/HMI (Solar Dynamics Obser- vatory/Helioseismic and Magnetic Imager) data of radial magnetic ?elds, it is found that in more than one hour before the appearance of the ?rst surge there emerged bipolar magnetic ?elds in the region of ejection. Besides, in several min- utes before the ejection of each Hα surge the magnetic ?uxes of positive polarity diminished. Via our analysis it is found that there appeared reconnections be- tween the newly emerging satellite magnetic ?elds and the preexisting magnetic ?elds in the spot, and this caused the continuous ejections of Hα surges.  相似文献   

Efficient Method for Computing with Certainty Periodic Orbits on a Surface of Section     

E. A. Perdios  V. S. Kalantonis  M. N. Vrahatis 《Celestial Mechanics and Dynamical Astronomy》2002,84(3):231-244

We present an improved method for locating periodic orbits of a dynamical system of arbitrary dimension. The method first employs the characteristic bisection method (CBM) to roughly locate a periodic orbit, followed by the quadratically convergent Newton method to rapidly refine its position. The method is applied to the physically interesting example of the two degrees of freedom photogravitational problem, and shown to surpass the CBM algorithm and Newton's method alone.  相似文献   

BOOK REVIEWS     

《The Professional geographer》1986,38(2):195-222

Book Reviewed in this article: The Vanishing Farmland Crisis, Critical Views of the Movement to Preserve Agricultural Land . John Baden Protecting Farmlands . Frederick R. Steiner and John E. Theilacker Ecological Effects of Fire in South African Ecosystems . Peter de V. Booysen and Neil M. Tainton Geography in China . Wu Chuanjun , Wang Nailiang , Lin Chao and Zhao Songqiao Resource Inventory and Baseline Study Methods for Developing Countries . Francis Conant , Peter Rogers , Marion Baumgardner , Cyrus Mc Kell , Raymond Dasmann, and Priscilla Reining Principles of Remote Sensing . Paul J. Curran Famine As A Geographical Phenomenon . Bruce Currey and Graeme Hugo The Suburban Squeeze: Land Conversion and Regulation in the San Francisco Bay Area . David E. Dowall Senses of Place . John Eyles Uneven Development and the Geographical Transfer of Value . D. K. Forbes and P. J. Rimmer Issues in Wilderness Management . Michael Frome Land-use and Prehistory in South-east Spain , The London Research Series in Geography 8. Antonio Gilman and John B. Thornes with Stephen Wise Regions in Question, Space, Development Theory and Regional Policy . Charles Gore The Colorado River: Instability and Basin Management . William L. Graf Hazardous Waste Sites: The Credibility Gap . Michael R. Greenberg and Richard F. Anderson Peasants, Subsistence Ecology, and Development in the Highlands of Papua New Guinea . Lawrence S. Grossman Silver Cities: The Photography of American Urbanization, 1839-1915 Peter B. Hales Silicon Landscapes . Peter Hall and Ann Markusen Remaking Ibieca: Rural Life in Aragon under Franco . Susan F. Harding The European Energy Challenge: East and West . George W. Hoffman The Global Climate . John T. Houghton The Urban Jobless in Eastern Africa . Abel G. M. Ishumi . The Tourist: Travel in Twentieth-Century North America . John A. Jakle City and Society: An Outline for Urban Geography . R. J. Johnston Residential Segregation, The State and Constitutional Conflict in American Urban Areas . R. J. Johnston Accessibility and Utilization: Geographical Perspectives on Health Care Delivery . Alun E. Joseph and David R. Phillips To the Heart of Asia: The Life of Sven Hedin . George Kish North American Culture , Vol 1. Ary J. Lamme III Past and Present in the Americas: A Compendium of Recent Studies . John Lynch Ethnicity in Contemporary America: A Geographical Appraisal . Jesse O. Mc Kee The Shell Countryside Book . Richard Muir and Eric Duffey 1990 Planning Conference Series. Proceedings of the National Geographic Areas Conference . Proceedings of the Regional Geographic Areas Conferences Wood, Brick, and Stone: The North American Settlement Landscape . Vol. 2: Barns and Farm Structures . Allen G. Noble Bangladesh: Biography of a Muslim Nation . Charles Peter O'donnell  相似文献   

不确定线-面拓扑关系的描述与判别   总被引：1，自引：0，他引：1  

杜晓初  黄茂军 《测绘学报》2007,36(3):340-343,350

不确定线状目标和面状目标之间拓扑关系的描述是空间信息处理过程中经常面对的问题。在对不确定线状目标和面状目标进行描述的基础上,对不确定线状目标与面状目标各组成部分之间的相交程度进行了定量表达,通过计算这些度量组成的空间向量与9-交集模型确定的空间关系向量之间的相关度,提出了一种不确定线状目标和面状目标之间拓扑关系的描述模型,通过定量的方法来对其空间拓扑关系进行判别。  相似文献   

球面四元三角网的基本拓扑关系描述和计算   总被引：6，自引：1，他引：5  

陈军  侯妙乐  赵学胜 《测绘学报》2007,36(2):176-180

球面四元三角网具有多分辨率和层次组织的特性,已成为目前研究球面问题的有效方法之一。本文在此基础上,利用引入集合多算子和对称差的欧拉数,给出描述和计算球面栅格拓扑关系的四元组模型。该模型利用两空间目标间的交(∩)、差(\)、被差(/)和对称差(Δ)的内容是否为空来初步区分相离/相接、交叉、相等、包含/覆盖、被包含/被覆盖这五对拓扑关系。然后通过引入对称差的欧拉数来进一步区分传统模型难以区分的相离/相接、包含/覆盖和被包含/被覆盖这三对拓扑关系。  相似文献   

大地电磁测深静态效应空间域拓扑处理技术研究     

刘桂梅  马为  刘俊昌  徐新学  郑国磊  刘正 《物探与化探》2018,(1):118-126

静态效应是大地电磁测深中普遍存在的技术难题,这一影响使得观测结果的处理解释出现无法接受的误差。针对现有大地电磁测深静态效应判别、校正及数据采集装置,提出了以野外实际观测资料为基础的空间域拓扑处理技术。在分析静态效应的成因、表象以及平面波电场分量叠加特性的基础上,从空间采样的实质出发,完善了拓扑点曲线求取公式,获取了同一记录点不同极距的观测结果,提取了连续阵列观测装置中所隐含的变极距观测信息;依据理论模型分析建立了局部不均匀体上不同部位各记录点随拓扑观测极距变化可能出现的静态偏移模型,初步建立了以点进行拟剖面处理,以剖面上所有点的单一频点构成拟平面图来进行拓扑结果图形展示和分析解释的基本方法,并编制了相应的软件包,从理论和实践上初步建立了空间域拓扑处理研究静态效应这一全新的方法技术。实验结果表明,拓扑叠加处理会使资料品质提高,静态偏移效应的判别可从多个方面进行,可有效反映出不均匀体所产生的畸变电场的空间分布,从而可在一定程度上显示出不均匀体的空间位置和分布形态,为认识表层电性结构提供了一种客观的实测信息。同时,由于拓扑处理使观测装置的各种变化所能测得的结果被提取出来,意味着一种新的抑制干扰方法的出现。  相似文献