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在分析现有地图信息度量方法的基础上,从地图信息来源入手,提出点状地图空间信息的构成即几何分布信息、拓扑邻接信息、聚群结构信息.进而,结合地图信息产生的差异性本质,建立了地图空间信息量度量的模型,即:基于特征的信息量模型.随后,从几何分布特征上选择点要素对应Voronoi区域面积、从拓扑邻接特征上选择Voronoi区域的一阶邻接度、从聚群结构特征上选择点数、分布面积和分布密度作为特征的定量描述指标,分别建立了几何分布信息量、拓扑邻接信息量、聚群结构信息量的度量方法.最后,采用两组地图数据试验对本文提出的方法进行验证,通过对比试验分析表明了本文所提方法的合理性和优越性. 相似文献
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《武汉大学学报(信息科学版)》1998,(1)
测绘学科博士学位论文摘要选登(一)题目:地图模式识别的原理、方法与实现作者:黄文骞导师:杨启和摘要:分析了模式识别、地图制图和地图模式识别的国内外发展现状;归纳总结了地图符号的构图规律,提出并改进了地图符号的链码、区域、拓扑和结构等计算机描述方法。具... 相似文献
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本文就地图符号学相关的问题展开了讨论和分析,重点分析了地图符号分类体系、地图符号构图规律、地图符号的受众问题以及地图符号的语义结构。地图符号是传榆地理信息的有效工具,但只有当地图制图者和地图使用者的认知结构一致或差异不大时,地图符号才能更加有效的传输信息和进行语义表达。本体技术将极大的推动地图符号学的发展。 相似文献
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对已有的地图信息量测量法进行介绍,针对已有的专题信息量测量方法单方面关注符号类型数量或拓扑邻接性,缺乏对影响专题信息量主要因素的分析提取的问题,分析提出影响专题信息的主要因素——符号类型数量、混合度和每种类型占比,在此基础上提出基于拓扑中心符号的专题信息量测量法、基于全局的专题信息量测量法和基于特征的专题信息测量法。实验表明,以上改进方法对地图符号专题信息量的计算结果更加有效,能够更好地符合人的空间认知特性。 相似文献
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提出了一种顾及结构和几何特征的道路网自动选取方法。综合考虑道路的度中心性、集聚系数和路划的几何长度等道路选取影响因素,提出一种道路重要性评价方法。实验结果表明,本文方法能够很好地保持选取道路网的整体与局部结构、拓扑结构以及路网连通性。基于该方法,由大比例尺地图选取出的小比例尺地图与相应标准比例尺地图保持较高的一致性,表明该方法是稳定可靠的。 相似文献
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高精度地图符号编辑器的设计与实现 总被引:1,自引:1,他引:0
地图符号给予地图极大的影响,它决定着地图内容能否充分表达,决定着地图是否便于阅读和使用,决定着地图信息的传输效果,而且地图符号的精度直接影响地图表示内容的准确性.结合地图符号理论,详细分析了点状符号、线状符号和面状符号的结构特点,提出了地图符号编辑器的设计方案及相应的关键算法,并且分别给出了控制点符、线符和面符精度的措施,实现了地图符号的高精度制作,而且设计的符号编辑器具有良好的封装性、可维护性和可适应性. 相似文献
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根据布尔代数的定义和充要条件,结合地图符号示冽,论证了地图符号系统是布尔代数系;阐述了地图符号系统的多层结构原理;通过在地图符号系统中定义等价关系建立层次的方法,探讨了机助地图制图中通过多层次代数运算建构地图内容的理论价值和实践意义。 相似文献
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夏永亮 《测绘与空间地理信息》2014,(8):155-156
道路网络自动综合是地图综合的主要研究课题。本文通过引入对偶拓扑理论建立了城市道路网络的对偶拓扑结构,并将道路的重要性表达为路网中所有道路的重要度贡献的总和,进而提出了一种道路网络自动综合方法。实验表明,本文方法可以较为合理地选取路网中相对重要的道路,所选路网保持了原始路网的整体形态及拓扑连通。 相似文献
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建设黄河“智能大脑”服务流域生态保护和高质量发展 总被引:1,自引:0,他引:1
本文首先介绍了黄河流域水文、地理景观和地貌特征,下游河道变迁和河口变迁历史及生态治理,流域历史水旱灾害等基本背景,分析了黄河流域生态保护和高质量发展面临的主要问题和具有的优势。然后重点论述黄河“智能大脑”如何服务流域保护和发展,提出黄河“智能大脑”三要素,即感知系统(天地一体智能感知网)、存储管理系统(资源池)和操作系统(时空大数据平台);论述了流域一体化时空大数据中心的构成及其基本功能,时空大数据平台及其目标要求,分析并提出了基于网格集成与弹性云的混合式时空大数据平台技术体制和构建技术,提出采用“共用时空大数据平台+”应用概念模型及其具体应用模式。最后讨论了时空大数据平台服务黄河流域城市数字化、网络化和智能化,加强流域上中下游7大城市群的新型智慧城市建设,推动流域生态保护和社会经济发展,提出基于流域时空大数据平台构建服务保护和发展的综合科技信息咨询服务平台,支撑流域协同创新共同体构建,增强流域整体性和协同性发展。 相似文献
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银川平原土壤盐渍化与中低产田遥感应用研究 总被引:10,自引:0,他引:10
土壤盐渍化是影响农业生产与生态环境的一个重要因素。长期以来,宁夏银川平原的次生土壤盐渍化问题十分突出,形成了许多盐渍型中低产田,影响和制约了区域农业的可持续发展。主要采用遥感解译方法提取了银川平原土壤盐渍化的分类与分布的现状信息。在此基础上,依据中低产田的分类标准,将相关的耕地类型、土壤肥力、作物产量、灌排水指标等因子转化成数字化专题图层,采用多源信息复合分类的方法,通过“综合分析,主导因子判定”实现了GIS辅助下的中低产田分类,为遥感和地理信息系统技术在土壤盐渍化和中低产田调查研究中的应用,探索出了一条可行的途径。 相似文献
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Yoshiaki Ohsawa Hirofumi Kagaya Takeshi Koshizuka 《Journal of Geographical Systems》2002,4(3):325-342
When demand points are given as a planar map where projection method is explicitly stated, we usually know the latitudes
and longitudes of these points from the map. Then we can solve the Weber problem on the globe, and we do not suffer from errors.
This paper analyses how cylindrical projections cause distortion in the Weber problem when demands are distributed on the
Northern Hemisphere. First, we demonstrate that planar solutions are always located south of the spherical solution if the
Mercator projection, the equirectangular projections with standard parallels near the demands, or the equal-area projection
with the same characteristic is chosen. Second, we verify that this geographical tendency is inclined to hold when the demand
points, are distributed symmetrically, widely or toward the north.
Received: 15 August 2001 / Accepted: 20 April 2002
This paper was partially written while the first author was visiting the Department of Geography at the Catholic University
of Louvain, Louvain-la-Neuve, Belgium [1993–1994]. He is grateful for the hospitality of this department. An earlier version
of this paper was presented in 1994 at the Seventh Meeting of the European Operational Research Working Group on Locational
Analysis in Brussels, and in 1996 at the Fifth World Congress of the Regional Science Association International in Tokyo.
The authors would also like to thank the participants as well as three anonymous referees for their constructive comments. 相似文献
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An empirical test of the competing destinations model 总被引:2,自引:0,他引:2
It has long been believed that properties of spatial structure have a strong effect on trip distribution, which thus leads
to a bias in the estimated distance decay parameters of spatial interaction models. This paper is an attempt to identify to
what extent the spatial structure effect affects the trip distribution and determine whether the incorporation of a term to
account for the relative location of destinations into the conventional gravity models, results in a model that can more correctly
represent the actual trip distribution. The main focus is on the comparison of the origin–specific estimates of the distance
decay parameter, calibrated from the traditional production-constrained model and the production-constrained competing destinations
model. The results show that the competing destinations model is superior to the conventional model in both reproducing the
interaction flows and giving behavioral explanation to the distance decay parameters, but the essential aim of the competing
destinations model to remove the map pattern from the distance decay parameters of the conventional model has not been identified.
Received: 5 September 2001 / Accepted: 17 June 2002
We are grateful to Gloria. A. Swieczkowski for kindly providing the migration data. The authors also gratefully acknowledge
the comments of the referees. 相似文献
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Evaluating the importance of accessibility to congestion response using a GIS-based travel simulator
Irene Casas 《Journal of Geographical Systems》2003,5(1):109-127
This paper examines the effect of accessibility on individual response to unexpected traffic delays and congestion. The dataset
used was collected by means of a travel simulator developed within a geographic information system (GIS) environment. The
simulator models a commute trip where congestion takes place, and subjects are asked to respond by making a choice among alternative
courses of action. Available alternatives for dealing with the unexpected traffic delay include changing the location of the
planned activities or changing the activities to be performed. Accessibility to the new locations and to the different activities
is computed using a cumulative measure. Analysis using CHAID tree technique found that accessibility is a good predictor of
subjects' choice when responding to unexpected traffic delays.
Received: September 2002 / Accepted: January 2003
Support for this research by a grant from the Center of Intelligent Transportation Research of the Ohio State University
is gratefully acknowledged. The author would also like to thank Joe Weber, Mei-Po Kwan and two anonymous reviewers for their
valuable comments. 相似文献