共查询到18条相似文献，搜索用时 140 毫秒
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为解决城市影响范围研究中忽略非匀质空间的问题,本文以光栅扫描算法为基础,提出了一种非匀质空间下面状加权Voronoi图生成算法。首先,对面状目标和栅格空间赋予不同的权重;其次,采用3×3邻域模板进行十字交叉4次光栅扫描,在距离变换中按栅格像元传递权重对距离进行分解,完成非匀质空间下面状加权Voronoi图的生成;最后,以山西省11个地级市为研究区,进行了验证。结果表明,改进后的算法实现了非匀质空间面状加权Voronoi图的生成;相比点状加权V图,城市之间权重差异较大,距离较近时,面状加权V图更适合城市影响范围划分。 相似文献
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随着我国新型城镇化规划的实施,如何识别城镇发展的不均衡,以及产生这些差异的原因已成为城镇化建设亟待解决的问题。本文利用Voronoi图的空间剖分特性,将城市中心性强度作为权重引入模型,建立山西省地级市加权Voronoi图,分析其空间影响范围,以判断山西省地级市发展的合理性和局限性;利用Delaunay图发现城市“空洞”,结合道路河流等矢量信息,通过叠加分析识别出待优先发展城镇;通过常规Voronoi图和变异系数Cv值判断本文模型的合理性和可行性。研究发现,山西省太原市的空间影响范围较大,导致周边地级市东西部发展较为不均衡;繁峙县、灵石县、新绛县条件较好,可以优先发展;通过常规Voronoi图和Cv值验证表明,本文所得结论与实际检验相符合。 相似文献
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基于加权Voronoi图的北京市湿地功能分区研究 总被引：1，自引：0，他引：1
湿地功能分区是城市湿地生态系统健康恢复、管理改善,以及资源可持续利用的重要前提。本文以北京湿地为例,利用客观赋权的主成分分析法对湿地生态服务功能进行综合评价;并结合空间分析中的Voronoi图空间分区方法,通过利用牛顿-断裂点模型确定属性权重的主要步骤,构建基于加权Voronoi图的城市湿地功能分区模型,开展"自下而上"定量化的北京湿地功能分区研究。结果表明:(1)北京湿地功能综合评价中,密云水库湿地的功能综合值最大,表明该湿地生态服务功能作用最重要。(2)北京湿地功能分区分为三级框架,其中包括4个一级核心湿地功能区、15个二级核心湿地功能区、43个三级核心湿地单元。(3)湿地资源功能价值量与湿地斑块空间关系的相结合,实现了属性和空间双重距离约束的湿地功能分区,促进了湿地生态系统服务价值评估在决策管理中的深入应用,为城市湿地功能区划提供技术支持。 相似文献
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汇水区划分是分布式水文模型计算的基础。针对现有方法使用DEM在平原城市地区划分的汇水区不符合实际地形情况,本文提出了一种面向城市平原地区分级划分汇水区的技术方法。该方法从城市用地分类角度出发将城市分为中心城区和郊区,依据城市排水主干水系进行汇水区一级划分,将影响中心城区和郊区的不同径流因子分别融入DEM中,利用细化的DEM进行二级汇水区划分;在此基础上,根据实际汇流情况,结合Voronoi图,对中心城区进行三级划分,最后通过GIS技术进行修正。该方法既结合了传统DEM生成子流域的算法,又融入了城市区域地物地貌特点,能更好地满足城市地区的需要。选择上海市嘉定区西北部地区为实验样区,利用该方法进行汇水区划分比较表明,其对于城市平原地区具有很好的适用性。 相似文献
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城市影响腹地范围的划分,在区域与城市规划中有着重要的理论和实际意义。本文从"城市结节性"和"空间交通可达性"两方面改进场强模型,采用主成分分析法与指标体系计算河南省城市结节性指数,利用累积耗费距离测算空间可达性,借助k阶数据场模型与水文分析模型,综合测度了1991年和2010年河南省17个地级城市的影响腹地范围及空间演变特征。研究表明,20年间河南省地级城市的平均可达本文时间从1991年的45.41 min缩短为2010年的33.03 min,空间场能显著增长且空间分异性显著。南阳的腹地面积增加最大,信阳的腹地面积缩小最大;安阳腹地面积增加率和漯河腹地面积减少率最大。郑州的腹地范围与其行政辖区偏移度最大。 相似文献
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一、Delaunay算法的基本原理 1．Voronoi图的定义 Voronoi图,又叫泰森多边形或Dirichlet图,它是由一组由连接两邻点直线的垂直平分线组成的连续多边形组成。N个在平面上有区别的点,按照最邻近原则划分平面;每个点与它的最近邻区域相关联。 相似文献
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本研究以Voronoi图为研究工具,对普通Voronoi图在海上救援应用中的局限性进行分析,并对其进行了合理改进,提出了“海上救援V图”。同时,结合模糊层次分析法和引力模型方法计算各海事机构救援力量的“吸引力”权重矩阵,提出了基于Voronoi图的海上救援调度模型。最后,结合具体救援案例,构建了基于Voronoi图的海上应急救援模型MRSV。实验结果表明：该模型能够在顾及海上特殊地理环境以及要素间空间关系的基础上,综合考虑各海事机构的救援力量,针对不同海难情况,选调合适的救援机构,调度结果合理,能够达到优化救援力量配置的目的,可以为目前海上应急救援力量调度提供参考。 相似文献
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采用可达性水平评价、经济联系分析、块模型等方法,研究了2009、2018年长江中游城市群的铁路可达性和经济联系空间格局,结果显示:从2009到2018年,长江中游城市群的铁路可达性改善明显,城市通达度提升,中心城市日常可达性范围扩大,尤其是1 h经济圈扩张明显,各城市的加权平均旅行时间显著降低,呈现"核心-边缘"格局,但差异增大;长江中游城市群形成以武汉、长沙、南昌为核心的放射状经济联系空间格局,且武汉、长沙的中心作用较南昌更明显,主要高铁沿线形成较高水平的经济联系带,剩余绝大多数城市间经济联系水平较低;长江中游城市群可划分为4个凝聚子群,其中环长株潭子群、武汉城市圈子群内部经济联系较强,4个子群内部联系显著高于相互联系,区域网络化格局尚未形成. 相似文献
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The coordinated development of Beijing, Tianjin and Hebei has been elevated as China’s important strategy. And, the priority in considering how to bring the maximum effect of their coordinated development into play is to delineate the spheres of urban influence with regard to the cities in the Beijing-Tianjin-Hebei Metropolitan Region. By building an evaluation index system of urban comprehensive strength, this paper applies the principal component analysis method to determine centrality strength of the cities, and the breakpoint theory and weighted Voronoi diagram to identify the spheres of urban influence in all central cities of the region. Results show that 13 central cities within the region greatly differ in strength, which can be classified into four tiers and that the spheres of urban influence do not have a high goodness of fit with administrative jurisdiction scope. Cities like Beijing, Tianjin, Shijiazhuang and Handan have larger spheres of urban, spheres of urban influence in Tangshan and Qinhuangdao are basically consistent with their administrative jurisdiction scopes, and seven cities including Langfang and Baoding have smaller spheres of urban influence. So according to these cities’ comprehensive strength and spheres of influence, the region can be divided into five plates: Beijing, Tianjin, Shijiazhuang, Tangshan and Handan. The major influence factors for inconsistency between spheres of urban influence and spheres of jurisdiction include difference in urban administrative ranking, small number of central cities with weak strength, discrepancy in the number of counties under jurisdiction, unreasonable spheres of jurisdiction and diversity in topographical conditions. In order to solve the imbalance in the spheres of urban influence and those of jurisdiction and better facilitate the coordinated development of the region, it is advised to adjust administrative areas so as to obtain more optimized urban spatial layout and more reasonable urban scale hierarchy system. 相似文献
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In metropolitan regions, the change in the strength of＂flows＂ between a core city and surrounding cities reflects the range of the core city＇s influence, while the gravity between core city and other cities reflects the strength of potential relation between them. This article firstly attempts to delimit the boundary of metropolitan regions with the two dimensions measure combining ＂flows＂ and gravitation. The former is measured through the flow of people between the core city and surrounding cities, and the latter is measured through both population and gross domestic products （GDP） of the core city and surrounding cities. The hierarchy of the cities within a metropolitan region is classified in order to emphasize the roles of the cities belonging to the metropolitan regions, different from the general way through population scale and administrative level, and is typical in China. This paper uses the Shanghai metropolitan region as a research case, determining boundary of this metropolitan region clearly and classifying hierarchy of the cities within the region. The final results are significantly different to previous work, even overthrowing the traditional system of urban hierarchy partly. It is helpful to highlight the function of cities in organizing the regional economy, the level structure of metropolitan regions, and each city＇s relative importance in a metropolitan region, which can be taken as scientific basis for planning integrated regions or urban systems. 相似文献
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《中国地理科学(英文版)》2020,(1)
In this paper, we use factor analysis to evaluate the urban comprehensive quality of each city in the Lanzhou-Xining(Lan-Xi) urban agglomeration. The time distance was obtained by using GIS spatial analysis, and the structure and pattern of the spatial network were analyzed by using the gravity model and social network analysis method. The results show that: 1) The scale effect of the Lan-Xi urban agglomeration is gradually emerging, and it is gradually forming the urban agglomeration with Lanzhou and Xining as the core, the Lan-Xi high-speed railway as the axis, and a high-dense connection. 2) Lanzhou and Xining are at the core of the Lan-Xi urban agglomeration, which has a strong attraction and spreads to neighboring cities. 3) In the network structure of the Lan-Xi urban agglomeration, Lanzhou, Baiyin, Gaolan, Yuzhong, Yongdeng, Dingxi, Lintao, Xining, Ledu, Huangzhong, Ping'an, Minhe and Datong are located in the network core position, which have the superiority position and lead to the entire regional communication enhancement and the regional integration development. 4) This urban agglomeration has significant subgroups, eight tertiary subgroups and four secondary subgroup; the tertiary subgroups which compose secondary subgroup have a close connection and mutually influence each other. 5) The Lanzhou Metropolitan Area and the Xining Metropolitan Area have an important impact on the surrounding cities, and the peripheral cities are basically controlled by the central city. The Dingxi subgroup, Lintao-Linxia subgroup, Gonghe subgroup have more structural holes than the subgroups within the Lanzhou Metropolitan Area and the Xining Metropolitan Area, so the peripheral cities of these subgroups have relatively less connection with surrounding cities. 相似文献
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城市潜能作为城市体系空间相互作用的代表性指标,反映了城市与其所在的城市体系内所有城市间相互作用的强度,即城市所具备的的集聚能力。合理分析城市空间布局及结构、探寻城市发展的空间差异,以及制定区域发展政策日益迫切,研究城市空间相互作用具有重要意义。本文以Globcover数据集提取中国大陆范围内26 619个城市斑块,获取了城市潜能计算时所需的城市斑块规模总量;同时,以DMSP/OLS夜间灯光影像为数据,提取能综合反映人类社会经济活动的城市斑块夜间灯光总强度,参与城市潜能的计算。利用潜能模型,依据城市斑块分层结果,以城市斑块规模和时间成本为参数,计算得到公里格网的城市潜能值模拟分布图,并分析了中国大陆城市潜能的空间分异特征。 相似文献
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This paper examines city growth patterns and the corresponding city size distribution evolution over long periods of time using a simple New Economic Geography(NEG) model and urban population data from Canada. The main findings are twofold. First, there is a transition from sequential to parallel growth of cities over long periods of time: city growth shows a sequential mode in the stage of rapid urbanization, i.e., the cities with the best development conditions will take the lead in growth, after which the cities with higher ranks will become the fastest-growing cities; in the late stage of urbanization, city growth converges according to Gibrat′s law, and exhibits a parallel growth pattern. Second, city size distribution is found to have persistent structural characteristics: the city system is self-organized into multiple discrete size groups; city growth shows club convergence characteristics, and the cities with similar development conditions eventually converge to a similar size. The results will not only enhance our understanding of urbanization process, but will also provide a timely and clear policy reference for promoting the healthy urbanization of developing countries. 相似文献
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《中国地理科学(英文版)》2021,(5)
As an important step enhancing regional innovation, researches on collaborative innovation have attracted much more attention recently. One significant reason is that cities can get excessive benefits while they take collaborative innovation activities. Based on the theories of innovation geography, this paper takes the collaborative innovation of the Yangtze River Delta(YRD) Urban Agglomeration as a case study and measures the collaborative innovation capacity from innovation actors and innovation cities by adopting the catastrophe progression model. Then on this basis, the study depicts the spatial pattern and the benefit allocation of collaborative innovation by using the coupling collaborative degree model and benefit allocation model of collaborative innovation. The results show that:1) The collaborative innovation capacity of cities in the Yangtze River Delta has strengthened largely, while the capacity still is not high enough. Cities with high collaborative innovation capacity are concentrated in Shanghai, the southern part of Jiangsu, and Hangzhou Bay, yet the cooperation of the universities-industries-research institutes need to improve. 2) The spatial pattern of collaborative innovation of the Yangtze River Delta presents several innovation circles, which are in Suzhou-Wuxi-Changzhou Metropolitan Circle, Nanjing Metropolitan Circle, Hangzhou Metropolitan Circle, Ningbo Metropolitan Circle, and Hefei Metropolitan Circle. Shanghai plays the role of the central city of collaborative innovation, while Suzhou, Nanjing, Hangzhou, Ningbo, and Hefei act as sub-central cities. 3) The benefit each city allocated from collaborative innovation activities has increased. However, the allocations of the benefit show that cities with higher innovation capacity have significant advantages in most cases, which lead to serious disparities in space. 相似文献
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基于提高城乡规划工作中城镇体系空间规划分析工作的准确性与效率的目的,本次研究提出了城镇势力圈划分、城镇职能识别、城镇规模等级划分定量分析方法。应用这些方法,基于ArcGIS 9.3系统平台基础上进行二次开发,设计了基于GIS的城镇体系空间规划分析系统。本系统适用于当前城镇体系规划实践,解决城镇势力圈划分、城镇职能识别、城镇规模等级划分等3个核心问题。本系统在城镇经济腹地划分、行政区划调整、经济协作区划定、中心城镇吸引范围的空间识别、中心镇判别、城镇体系结构识别等领域具有应用价值。 相似文献
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《中国地理科学(英文版)》2020,(3)
Urban agglomeration research has received increasing attention in China's national development strategies, and has become a hot topic in academic research. This study develops a theoretical framework that explores the formation mechanism and expansion process of urban agglomerations from the perspective of industrial evolution, and identifies the development issues and their causes by taking Yangtze Delta and Beijing-Tianjin-Hebei urban agglomerations as case studies. In the process of urban agglomeration formation within a free market, as has happened in Yangtze Delta region, the central city develops first, its secondary industry is then transferred to its neighboring cities, and the work division and cooperation with the neighboring cities is gradually established. However, in the 1990 s, aiming to become an international metropolis, Beijing implemented a series of administrative policies to encourage the reduction of the secondary industry and the development of the tertiary industry, before its secondary industry were fully developed and transferred to its neighboring cities. This delayed the integration process and the development of the Beijing-Tianjin-Hebei urban agglomeration. This study builds a good foundation for the construction of the theoretical system's urban agglomeration study, and provides references for decision making in an urban agglomeration development. 相似文献