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111.
1 IntroductionThesystemoflanduseisaverycomplexsystem .Wedrawuptheprojectoflanduseplanningstructuretoimplementtheopti mizationoflandresources .Theoptimizationoflandusestruc tureisthekerneloflanduseplanning .Today,mostoftheurbanlanduseplansonlyconsidertheop…  相似文献   
112.
基于2018年多时空高分辨率全球城市边界解译数据,从省域、市级和县区级3个尺度测算黄河流域城镇土地经济密度,并综合应用泰尔指数、空间自相关分析、地理探测器探等方法探讨其空间格局及影响因素。研究结果显示:① 黄河流域城镇土地经济密度总体不高,在县区尺度上68.3%的县区土地经济密度低于平均水平,空间分布总体上呈东高西低的态势,高土地经济密度的县区主要集中在以郑州为中心的中原城市群和山东沿海地区;在市级尺度上,57.5%的城市土地经济密度低于平均值,空间分布上集中在中下游地区,空间分布不均衡,以河南省最为显著。② 黄河流域城镇土地经济密度在地市尺度和县区尺度都表现为显著的空间正相关,其中高值集聚区(HH)集中在中原城市群和山东半岛城市群,低值集聚区(LL)集中在陕、甘、宁等西部地区,低值异质区镶嵌分布在中原城市群和山东半岛城市群周围。不同尺度上的空间集聚区的空间分布范围也表现一定的差异,在县区尺度表现出了局部性和分散性特征。③ 人均GDP、人口规模、地方财政科技教育投入、二三产业劳动力密度、区位质量指数等对黄河流域城镇土地经济密度影响较大。同时在黄河流域上游、中游和下游地区表现一定的差异性,总体来说,资本投入强度、人均GDP和区位质量指数对于上游、中游和下游的城镇土地经济密度都有较高的解释能力。  相似文献   
113.
在分析地图目标移位及面目标变形一般约束条件的基础上,利用骨架线划分面目标的空间结构层次,并通过制定相关的参数赋值策略,应用有限元方法求解移位过程中的面目标变形.  相似文献   
114.
基于空间实体约束的空间聚类算法研究   总被引:2,自引:2,他引:0  
高飞  樊明辉  陈崇成  江先伟 《测绘科学》2008,33(1):45-47,57
空间实体的存在对空间聚类分析产生重要的影响,传统的空间聚类分析中没有考虑空间实体的约束作用,从而影响了聚类结果。本文在总结了以往的空间聚类算法的基础上,提出了一种改进的基于空间邻接关系的空间聚类算法,该算法将空间邻接关系和空间实体作为约束条件嵌入到整个聚类过程中,使得数据对象的归类受到"就近原则"和"约束条件"的双重限制。  相似文献   
115.
The quality and integrity of spatial data is very important to support interoperability among different systems. To reach this aim integrity rules defined by the application play an important role (for example, constraints between object classes). In this article, we propose a methodology to define integrity constraints using user level spatial relations between classes of individuals. We will also provide mapping rules from user level relations to geometric level operators to allow the computation of relations. As a case study, we will define the constraints for the class of rivers and some of its specializations.  相似文献   
116.
国外关于年代际气候变率的研究   总被引:28,自引:2,他引:26  
王绍武  朱锦红 《气象学报》1999,57(3):376-384
文中指出在气候变率与可预报性研究计划中,列出年代际气候变率及可预报性研究子计划充分显示出这个问题的重要性,回顾并总结了近年来年代际气候变率的研究成果,特别对全球气候变暖、海气相互作用、温盐环流、自然气候变率和ENSO的年代际变率的研究几个重点问题进行了讨论,最后对年代际气候变率研究今后的发展方向提出了看法。  相似文献   
117.
Despite a long-term focus on learning in natural resource management (NRM), it is still debated how learning supports sustainable real-world NRM practices. We offer a qualitative in-depth synthesis of selected scientific empirical literature (N?=?53), which explores factors affecting action-oriented learning. We inductively identify eight key process-based and contextual factors discussed in this literature. Three patterns emerge from our results. First, the literature discusses both facilitated participation and self-organized collaboration as dialogical spaces, which bridge interests and support constructive conflict management. Second, the literature suggests practice-based dialogs as those best able to facilitate action and puts a strong emphasis on experimentation. Finally, not emphasized in existing reviews and syntheses, we found multiple evidence about certain contextual factors affecting learning, including social-ecological crises, complexity, and power structures. Our review also points at important knowledge gaps, which can be used to advance the current research agenda about learning and NRM.  相似文献   
118.
首先介绍地形网修测中常规判读地物地貌发生变化的方法,以及将变化检测技术应用于地形图修测中的必要性;其次介绍变化检测的基本原理、发展历史、国内外对变化检测概念的不同定义以及变化检测技术的特点和应用范围;紧接着从地形图快速修测这一客观需要出发,简明扼要地叙述变化检测方法的选择、变化检测的一般过程、变化检测结果在地形图修测中的应用,并结合变化检测的精度评估公式分析将变化检测技术应用于地形图修测工作中的实际效率;最后展望变化检测技术在地形图快速修测中的应用前景。  相似文献   
119.
The displacement operator is an important and still a hot topic in map generalization. In the generalization product, symbols must be unambiguous and easily perceived and readily understood, which makes space competition among features an important obstacle in the process of map objects displacement. Space conflict between objects, through propagation process, may be spread and more objects may drift into it. In order to maintain symbols equilibrium and spatial relationship between objects, some unimportant symbols or parts of symbols should be distorted under constraints according to visual graphic resolution thresholds to figure out space competition among map features. Three constraints including position, legibility and characteristics are important for the maintenance of symbols equilibrium and spatial relationship, which are discussed in this paper. The skeleton is introduced to represent area objects figure characteristic, in which an area object can be separated to parts hierarchically according to their importance in the construction. Then, the finite element method is applied to the map objects’ displacement and distortion, in which a strategy for the parameters of finite element method is discussed. Supported by the National Science Foundation of China (No.40401050), the Leading Academic Discipline Project of Shanghai Educational Committee (No.J50104), the Science Foundation of Shanghai Education Department (07ZZ09).  相似文献   
120.
Studies investigating the many ecologically and economically important species in benthic boulder habitats often use artificial boulders for determining species colonization. In some cases square‐edged blocks are used that are shaped much differently than the ovoid or ‘round’ boulders often occurring naturally. Here it was tested if the shape of boulders affects the distribution across the boulder surface of crustose coralline algae (CCA), a taxon that strongly influences ecological dynamics in this habitat. The distance that CCA extends from the edge of boulders toward the centre of the underside was measured, and it was found that CCA extended further underneath boulders that were round‐shaped compared with those that were block‐shaped, probably because of light reaching further underneath round boulders. This result shows how at least one important taxon can be affected by variation in the shape of these boulders. Hypotheses being tested that use artificial substrata to model naturally occurring boulders should be carried out only in places where the artificial and naturally occurring boulders match physically.  相似文献   
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