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Obtaining spatial similarity degrees among the same objects on multi-scale maps is of importance in map generalization. This paper firstly defines the concepts of ‘map scale change’ and ‘spatial similarity degree’; then it proposes a model for calculating the spatial similarity degree between a river basin network at one scale and its generalized version at another scale. After this, it validates the new model and gets 16 points in the model validation process. The x-coordinate and y-coordinate of each point are map scale change and spatial similarity degree, respectively. Last, a formula for calculating spatial similarity degree taking map scale change as the only variable is obtained by the curve fitting method. The formula along with the model can be used to automate the algorithms for simplifying river basin networks. 相似文献
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地图综合的本质是一种空间相似变换,制图者在相似原则的指导下实施概括,读图者从包含相似性的地图中形成心象地图、重构现实世界。因此,多尺度地图空间中的相似关系研究非常重要。然而,由于相似的可计算性差,且其计算的目的在于揭示更深层次的信息,地图综合中相似关系尤其是语义相似关系的研究相对较少。针对这一问题,本文以语义功能区约束下的大比例尺街区式居民地合并（1∶1750至1∶4000）为例,基于匹配距离模型计算建筑物合并中的语义相似度,得到语义相似度在关键比例尺节点的值,并对结果进行分析、评价。试验表明,语义功能区约束下的建筑物合并符合读图者的地图认知需求,本文所述方法有助于地图更好地发挥信息传输载体的作用。 相似文献
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如何快速、自动地实现多尺度地图自动综合结果质量评价,对提高空间数据质量、加快空间数据生产周期等具有重要意义.本文在综合考虑拓扑关系、方向关系和距离关系的基础上,基于SRM模型提出了基于面状目标的空间关系相似性的度量方法,为地图自动综合提供空间关系评价和维护的参考. 相似文献
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等高线拓扑关系定量表达对空间认知、地形特征挖掘、地图综合等至关重要。然而,已有研究多针对等高线树的生成及综合算法,缺乏等高线拓扑关系及其与尺度变化关系的定量表达,不同地貌类型其变化规律是否一致仍未知。为此,通过分带与投影转换、非闭合等高线拓扑检查与闭合及有向等高线树的构建等,发展了一种等高线拓扑关系定量表达方法。采用高山、中山、平原地貌60组多尺度等高线数据集,探究不同地貌类型的多尺度等高线拓扑指标及其随尺度变化规律的一致性。试验结果表明,相邻尺度等高线拓扑指标变化规律符合空间认知与推理,不同地貌类型多尺度等高线拓扑指标与尺度变化间关系可用同一个幂函数定量表达,该结论为基于多尺度空间相似关系等高线全自动综合的实现提供了理论支撑。 相似文献
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To overcome the weakness of modelling the relationships between map objects that represent the same geographic entities or phenomena at different times and scales, an agent-based approach is presented to modelling of the spatial evolution of map objects for better understanding of the evolutional process of different maps. Map agents are used to establish and manage the many-to-many corresponding relationships between map objects, and they render map objects active rather than traditionally passive. The evolutions of map objects are modelled by map agents using association and generation relationships to model the connectivity between map objects. This effort reduces the workload of multi-scale map updating by avoiding update of the entire map; instead, it simply allows map agents to detect, perceive and choose suitable behaviours on which to operate and update a spatially evolving object. Experiments of specific examples are presented to demonstrate the feasibility and the effectiveness of our approach. 相似文献
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互联网用户参与的地图制图容易出现视觉冲突、压盖、拥挤等地图表达问题,需要引入地图自动综合协助解决。网络地图中由于原图比例尺和综合后比例尺均难以准确量化,常规地图自动综合基于“原图比例尺-综合后比例尺”判断是否需要综合的方法已不再适用。矢量数据在可视化后会产生视觉粘连,视觉粘连越明显,地图表达效果越差,综合的需求也越强烈。基于此规律,本文提出对视觉粘连进行定量描述并据此判断是否需要综合。首先,从人类视觉感受出发,结合栅格化思想设计了矢量曲线视觉粘连的量化指标——视觉清晰度。然后,基于“金字塔式”的尺度空间计算曲线在多个比例尺表达的清晰度,并拟合了清晰度的变化函数。最后,将该函数应用于众源地理数据的网络地图综合决策。试验结果表明,本文方法可准确判断每条矢量曲线是否需要综合,能有效解决地理数据尺度异质性带来的可视化难题。同时,清晰度变化函数将曲线的尺度描述由静态数值扩展到连续函数,有望更好地支持多尺度空间数据处理及网络地图综合等问题。 相似文献
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针对建筑群自动综合结果质量评价问题,该文提出一种建筑群多尺度表达中空间相似度计算模型。从地图综合质量评价的角度,立足地图综合的3个约束,即图形约束、拓扑约束、结构约束,分别计算了图形相似度、拓扑相似度、结构相似度,并对以上各相似度作了适当的权重分配,计算建筑群目标的整体相似度。最后,通过实验验证了本文相似度计算方法的正确性、可行性。 相似文献
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连续多尺度表达是当前地图制图领域中的热点问题之一,常规地图采用多级瓦片剖分、多版本存储技术实现空间多尺度表达,存在数据量冗余、跨级别不一致、瓦片间尺度跳跃大等问题。结合传统地图综合、多尺度表达数据结构和空间索引建立等多种策略,在目标数据模型中加入尺度维和操作信息,记录地图综合的过程和尺度变换,建立空间数据矢量金字塔模型。该模型离线综合获取多级基态尺度表达数据,确定每个目标的尺度表达空间范围,并通过面向对象建模技术将目标表达状态及其纵向关联关系、算子类型及控制参量等信息封装在多尺度目标中;同时,建立一端或两端控制的尺度变换结构。基于该模型可快速获取适应用户需求的连续尺度表达状态。 相似文献
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《制图学和地理信息科学》2013,40(4):317-331
Automation of map generalization requires facilities to monitor the spatial relationships and interactions among multiple map objects. An experimental map generalization system has been developed which addresses this issue by representing spatial objects within a simplicial data structure (SDS) based on constrained Delaunay triangulation of the source data. Geometric generalization operators that have been implemented include object exaggeration, collapse, amalgamation, boundary reduction and displacement. The generalization operators exploit a set of primitive SDS functions to determine topological and proximal relationships, measure map objects, apply transformations, and detect and resolve spatial conflicts. Proximal search functions are used for efficient analysis of the structure and dimensions of the intervening spaces between map objects. Because geometric generalization takes place within a fully triangulated representation of the map surface, the presence of overlap conflicts, resulting from individual operators, can be detected due to the introduction of singularities in the triangulation, the structure of which is used to generate displacement vectors to resolve the conflict. Examples of the application of the implemented operators are described and illustrated using large scale topographic map data. 相似文献
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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
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在地图制图综合中必须保持不同尺度同一区域地图要素之间拓扑关系的一致性,但目前有关的一致性评价方面的研究较少,本文讨论了不同比例尺地图中居民地与道路之间拓扑关系一致性的模糊评价问题。从制图规则和视觉限制的角度,分析了多尺度地图表达中居民地与道路之间的应该保持拓扑关系的一致性的几项规则;基于模糊数学理论提出了制图综合中拓扑关系的一致性评价模型,并通过一个简单实例证明了该方法的可行性。 相似文献
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一种多比例尺GIS方案及其数据模型 总被引：14，自引：1，他引：14
提出了一种分层分级分区式多比例尺GIS方案，在提出的空间数据模型基础上，按照地图综合方法，发展了适合本文方案的多比例尺GIS空间数据模型，并通过试验说明了新方案及其模型的正确性和可行性，讨论了实施中几种情况的解决办法。 相似文献
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作为土地利用图综合的一个重要组成部分，线状要素综合质量的好坏对于有效提高自动制图综合的正确率具有重要意义。本文基于模糊综合评判理论对土地利用图中线状要素的综合进行了质量评价。首先，基于制图综合约束，确定评价指标体系，组成评价因素集；其次，在确定评判集和权重集的基础上，建立线状要素综合质量评价模型；最后，利用试验验证了评价方法的有效性。该研究为客观评价土地利用图中线状要素的综合质量提供了新的思路。 相似文献
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交互式地图综合过程中的符号可视化问题 总被引：4，自引：2，他引：2
针对计算机地图综合仍然以人机交互的方式为主的现状,本文根据地图综合操作中的符号可视化的四个特点,提出了建立以单套比例尺符号库适宜多套比例尺地形图数据的可视化方案。通过定义不同比例尺之间符号的衰减系数,讨论了单套比例尺可视化多套比例尺数据的实现方式,并结合1:1万地形图缩编至1:5万地形图进行了模拟实验。 相似文献
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《制图学和地理信息科学》2013,40(3):232-248
Successful implementation of an intelligent system for automated map generalization requires formalization of cartographic principles that are, in many cases, only intuitively understood. Formalizing these principles requires acquisition and re-expression in the form of semantic nets, frames, production rules, or similar formalization methods. The various techniques for cartographic knowledge acquisition have been discussed on a theoretical basis; however, little empirical research has been conducted. This paper reports on empirical acquisition of cartographic knowledge by reverse engineering; that is, on trying to recapitulate decisions made on published documents or maps. The work is based on a computer-assisted multi-scale inventory of the Austrian National Topographic Map Series. Queries of the relational database, within which inventory data are stored, lead to the formulation of prototype production rules for modifying map symbols during automatic scale changes. Components of map generalization expressed in such rules include the selection behavior of settlement, transportation, and hydrographic objects, and the degree of simplification of settlement domains and building clusters. The acquired cartographic knowledge reveals quantitative relations between map elements and the changes in these relations that occur with scale transition. These insights can guide subsequent knowledge refinement using other acquisition methods. This paper provides, in addition, a conceptual framework by which other topographic map series may be compared at multiple scales. 相似文献
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Fourier-based multi-scale representation and progressive transmission of cartographic curves on the internet 总被引：1，自引：0，他引：1
ABSTRACTAutomatic generation of multi-scale representations from the same spatial data source has been the research focus in map generalization for a long time. Based on the Fourier technique, this paper proposes a continuous, multi-scale representation model for progressive transformation of cartographic curves on the Internet. In our method, all the curves, whether closed or open, are depicted as periodical functions which are further expressed as Fourier series. The convergence degrees of the Fourier series are explored for different kinds of curves, and truncating frequencies are derived based on the similarity between the original and reconstructed curves. Using information theory and the Radical Law in cartography, the relationship between map scales and Fourier frequencies is established. Based on the proposed multi-scale model, we also introduce the principles and implementation of a progressive transmission method. Our method is evaluated using the contours from a topographic map. The results show that our model is a valid approach to multi-scale representation of cartographic curves. 相似文献