面向带洞面状对象间的拓扑关系描述模型   总被引：1，自引：1，他引：0  

沈敬伟  周廷刚  朱晓波 《测绘学报》2016,45(6):722-730

为研究带洞面状对象间的拓扑关系,提出了一种25IM(25交集模型)。以点集拓扑理论为基础,对带洞面状区域的内部、边界和外部进行定义。分析了9IM(9交集模型)在表达带洞面状对象间拓扑关系方面存在的问题,将带洞面状对象分为内部、外边界、内边界、外边界外部、内边界外部共5部分,提出了一种5×5的矩阵模型,即25IM。基于点集拓扑理论,定义了8条规则来排除不符合逻辑的拓扑关系。基于25IM,对8种基本拓扑关系:相离、相接、重叠、覆盖、包含、相等、被覆盖和被包含,进行细分描述。结果表明,本文提出的25IM能够更为详细地表达带洞面状对象间的拓扑关系。  相似文献   

An improved method for mapping tidal waterways based on remotely sensed waterlines: A case study in the Yellow River Delta,China     

Xiang Yu  Chao Zhan  Mengquan Wu  Xueli Niu  Xueyu Zhang 《Marine Georesources & Geotechnology》2020,38(8):887-895

Abstract

Tidal waterways perform as the paths through which seawater invades. Their spatial-temporal variation with the shift in Yellow River’s route requires the accurate measurement of their status. Visual interpretation for delineating tidal waterways is inefficient due to a substantial amount of work. Buffer analysis provides an alternative to visual interpretation. However, it is difficult to use the buffer distance threshold to identify tidal waterways from other freshwater bodies. In this study, we present a straightforward method for mapping tidal waterways. First, we adopted the normalized difference water body index (NDWI) to extract water bodies. Waterlines were subsequently delineated based on a morphological opening filter with a kernel of 9?×?9. Finally, tidal waterways were mapped based on the proposed topological relation in ArcGIS. We showed the utility of this approach by mapping tidal waterways in the Yellow River Delta, China. The proposed method enables tidal waterways be mapped precisely and was replicable and universal in other similar studies.  相似文献   

Resource use conflicts in Mabini and Tingloy,the Philippines     

Terhi Majanen 《Marine Policy》2007

This paper presents the results of an analysis of resource use conflicts in areas near marine protected areas in Mabini–Tingloy, the Philippines. The author found large differences between groups of stakeholders in terms of perceived benefits and costs of conservation and tourism, and these inequalities have led to conflicts between various stakeholder groups. Marked by unequal power relationships, the conflicts place subsistence fishers as the weakest stakeholders. Fishers also have the lowest rates of knowledge of and participation in conservation activities. The study concludes that in order for conservation programs to be effectively transitioned onto the social and legal fabric of Mabini–Tingloy, resource use conflicts need immediate attention.  相似文献   

基于等角度变比例投影的矿体轮廓线自动匹配方法研究     

田宜平  刘维安  张夏林 《地质科技通报》2020,39(1):175-180

详细讨论了基于矿体轮廓线的三维建模方法中涉及的匹配对应、分支和构面建模等主要问题.针对轮廓线匹配问题提出了一种以矿体整体走向为投影方向,以相邻剖面中轮廓线总面积之比为缩放比例的等角度变比例投影算法,将不共面的轮廓线投影到同一平面中以完成共面轮廓线的匹配拓扑分析,从而解决轮廓线的对应问题.为了解决轮廓线的分支问题,设计了一种距离反比加权平均和样条函数相结合的自适应插值算法.最后通过采用实际矿山数据建模,对本文所提出的方法进行了有效性验证.  相似文献   

复合地块的拓扑类型计算与应用     

陈斐  周晓光 《测绘信息与工程》2012,37(6):52-55

按照简单地块的8种拓扑关系分类定义,计算简单地块的拓扑关系。将复合地块的外边界与空洞分离为m＋1个（m是空洞数）简单多边形,分别计算外边界之间、空洞之间、外边界与空洞之间的拓扑关系,并且按照不同的拓扑关系组合,计算复合地块的8种拓扑关系。  相似文献   

Economic diversification and second‐tier political conflict: Assessing bitumen political ecologies in southwest Nigeria     

Godwin Uyi Ojo 《Singapore journal of tropical geography》2012,33(1):49-62

Since its emergence as a research field in the 1980s, political ecology has provided a useful tool to explicate violent environments, notably as hallmarks of natural resource‐dependent economies. Practitioners regularly address what might be called ‘charismatic’ natural resources such as oil and other precious minerals to describe contestation over access and control of natural resources. Yet, where this focus exists, the political ecology of less economically valuable or ‘noncharismatic’ resources is thereby obscured. Thus, Nigeria's dependency on oil production has generated much scholarly attention with its unstable political economy described as a rentier state. In contrast, this paper draws on extensive field experience and knowledge about the country to assess in a preliminary manner some of the dimensions and ramifications of a less well known second‐tier natural resource commodity that is gaining attention as part of a possible national economic diversification strategy. Using the case of bitumen, a viscous hydrocarbon mainly used in road surfacing and roofing work, I assess the trajectory of this relatively overlooked resource, thereby opening a window onto the political ecology of a noncharismatic resource. In contrast to the ubiquitous violence in the oil‐based Niger Delta, I suggest that bitumen political ecologies, while also provoking political conflict and debate, nonetheless seem to being marked by new power dynamics that might augur a less violence prone path in terms of Nigeria's political economy of natural resource production.  相似文献   

时态地理信息系统研究进展和问题   总被引：1，自引：0，他引：1  

韩涛  张永忠 《干旱气象》2004,22(3):77-82

简要回顾了国内外时态GIS(Temporal GIS)发展历史,从地理时空认知、时空拓扑关系、时空系统理论、时空数据模型以及动态过程模拟等几方面总结了国内外时态GIS研究现状,展望了时态GIS进一步研究必须解决的几个问题。  相似文献   

GTP模型中四面体的引入及其空间模型扩展   总被引：7，自引：3，他引：4  

王彦兵  吴立新  史文中 《地理与地理信息科学》2003,19(5):16-19

该文从空间拓扑概念出发,分析了基于广义三棱柱(GTP)模型建立空间实体间拓扑关系时的不足。针对GTP进行平面剖切时存在的缺陷,讨论了在GTP模型中加入新的几何元素——四面体作为辅助元素的必要性,并将空间实体的描述分为几何元素和实体元素两类。在此基础上,对原有GTP模型进行了改进,建立了几何元素和实体元素之间的拓扑关系。并有效地解决了空间实体的3D平面剖切问题。  相似文献   

Topology-based proximities in spatial systems     

Roderic?Beraclaramunt@ecole-navale.fr" title="bera  claramunt@ecole-navale.fr" itemprop="email" data-track="click" data-track-action="Email author" data-track-label="">Email author  Christophe?Claramunt 《Journal of Geographical Systems》2003,5(4):353-379

This paper introduces several topology-based measures that characterise proximity relationships between regions in a spatial system. These measures are derived from a relative adjacency operator that is computed from the dual graph of a spatial system. The operator is flexible as the respective importance of neighbouring and outlying regions can be parameterised. Given a reference region in a spatial system, we also show how the relative adjacency supports the analysis of the relative distribution of other regions, and how these regions are clustered with respect to that reference region. Extensions of the relative adjacency integrate additional spatial and thematic criteria. The properties of the relative adjacency are illustrated by means of reference examples and a case study.The authors thank the referees for their constructive comments and suggestions that significantly improved the quality of the paper.  相似文献   

闭合坐标链多边形数据的拓扑关系快速构建   总被引：5，自引：0，他引：5  

罗芳  艾廷华  王洪 《武汉大学学报(信息科学版)》2004,29(6):558-561

基于格网化的思想，提出针对该数据快速构建拓扑关系的算法。该算法有效利用了闭合坐标链多边形数据本身具备的多边形几何信息。试验证实，该算法提高了运算速度。  相似文献