共查询到20条相似文献，搜索用时 125 毫秒
1.
《地理与地理信息科学》2017,(2)
数字环境下的计算机自动制图综合质量评价,其本质就是计算综合前原图和综合后结果图之间的相似度,因此该文提出了基于空间相似关系对居民地群组地图要素的制图综合质量进行评价的方法。首先,根据多尺度空间相似关系的定义,提取出居民地群组多边形的特征因子并计算各因子综合前后的相似度;其次,在合理分配权重的基础上,建立居民地群组多边形总体相似度计算模型,并根据相似度计算结果对居民地群组目标要素的制图综合质量进行评价;最后,利用实验验证了该文所提评价方法的有效性。该研究为客观评价地图综合质量提供了一个新的思路。 相似文献
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自2000年以来开始出现的大量仿制景观,从经济、社会、文化和政治方面重塑了中国的城市空间,但却没有引起学者的普遍关注。以新兴出现的微型仿制景观——佛山日本街为例,运用实地调查和话语分析方法,首先理清佛山日本街的仿制要素及其特征,以及佛山日本街的兴起原因,其次利用社交平台的文本数据分析新媒体影响下佛山日本街的形象塑造,进而探讨佛山日本街不同形象的产生根源。研究发现,佛山日本街的仿制要素虽受到日本城市街道形态以及ACGN亚文化的启发,但本质上是一种文化借用式的网红打卡地;资本竞争和新型社交方式是佛山日本街兴起的主要动力要素,而新冠肺炎疫情影响下的旅游环境变化进一步刺激和提升了佛山日本街的打卡热度和知名度;在新媒体的影响下,社交平台用户对佛山日本街的讨论主要聚焦于文化原真性和抄袭侵权两个方面,导致其塑造的形象正面、负面并存。 相似文献
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一种基于面积平衡约束的图斑化简算法 总被引：1，自引：0，他引：1
保持综合前后各地类土地面积平衡是土地利用数据综合的基本原则.地类图斑是面积统计的最小单元,用常规的线化简算法不但难以保证图斑的地理特性,而且会给面积统计带来不确定性.该文提出一种能够使图斑化简前后面积保持绝对平衡的化简算法,该算法给出了求取图斑群和岛图斑的地理特征点、几何特征点的相关方法,对被特征点分割的综合子弧段运用直线面积平衡和参数曲线面积平衡两种求取平衡线的方式进行化简,基本原理是综合前后弧段切割它们自身的包络矩形面积比相等,且综合后的弧段须落入综合前子弧段的误差缓冲区内.实验表明,该算法不但能保持图斑的形态特征,而且能保持图斑化简前后面积绝对相等. 相似文献
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基于遗传算法思想,针对地图综合中离散面群居民地的选取,考虑地图综合需要保持的统计、专题、拓扑和度量等4类关键信息,提出一种基于遗传多目标优化的离散面群居民地的自动选取模型。该模型考虑了面积、密度、属性意义等多种约束指标,通过遗传迭代,逐步优化得到理想结果。采用1∶10 000居民地数据进行了地图综合实验,结果表明,该算法能够有效保持地图所包含的关键信息。 相似文献
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现有对城市公园绿地利用的评价多从人均公园绿地面积、绿地覆盖率等指标衡量,忽略了对绿地使用者(城市居民)的关注,致使很难真正从评价结果得知公园绿地的空间配置是否合理。从公园绿地的可达性与居民的访问偏好等要素着眼,探究两者匹配程度,采用腾讯宜出行及百度规划路径时间等开源大数据,更具客观性、真实性地评价了郑州主城区公园绿地。结果表明:郑州主城区街旁绿地访问密度均值最高,专类公园访问密度均值最低,街旁绿地可达性高,社区公园次之,专类公园可达性在部分区域较好。郑州主城区公园绿地整体利用匹配度较差,其中综合公园利用匹配度最高,社区公园与街旁绿地次之,分布在郊区的专类公园匹配度最低,未能被妥善利用。绿化程度、社会活力、地价、绿地面积和形态指数对城市公园绿地的利用匹配度有影响,但对不同种类的公园绿地影响程度不同。因此,可以有选择地提高这些指标来改善相应公园绿地的利用匹配度。 相似文献
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非连续分布面状地理现象的图形自动概括方法 总被引：8，自引：3，他引：8
本文首先阐述了图斑概括过程中应遵循的原则,即正确处理几何精确性与地理真实性、清晰性和详细性两对矛盾,继而提出了自动化制图综合的设计策略。然后探讨了非连续分布面状地理现象(即图斑)的自动取舍、化简、夸大和移位、以及合并等算法,介绍了上述算法的实现方法,并给出几种地物图形自动概括的应用技术流程。 相似文献
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针对基于线性和岛屿约束的Delaunay三角网构建算法的不足,从减少算法计算机实现步骤出发,研究改进了线段相交判断、首三角形确定等影响域多边形搜索相关算法;在分析当前存在的多边形三角剖分算法基础上,给出了存在重复点(悬边)的多边形三角剖分算法;在影响域多边形搜索阶段充分利用多边形间的拓扑关系信息,消除了岛屿约束内部三角形删除时需遍历三角形数据的不足.算法涵盖线性和岛屿约束的构建,综合性强,效率高且易于实现. 相似文献
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针对GIS中线状、面状等复杂形态地理要素,提出一种构建任意发生元Voronoi图的实用算法.主要步骤包括:将复杂发生元离散为点集;对点集采用扫描线算法构建Voronoi图,构建过程中对所生成的Voronoi多边形以其发生点所在要素的序号赋属性值;根据拟定的规则进行Voronoi多边形的合并,得到面向复杂发生元的广义Voronoi多边形,每个复杂发生元有且仅有一个Voronoi多边形与之对应.论述了算法实现的关键过程,并结合实例验证了该方法的可行性,算法的执行效率相对较高. 相似文献
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昆明城市居民的游憩活动空间研究 总被引：3，自引：0，他引：3
以昆明市为案例地,通过问卷调查,从城市居民的游憩空间及相关影响因素分析了城市居民游憩空间的一般规律,建立了昆明城市居民的游憩空间模型,提出了城市游憩设施与规划建议.研究表明,昆明城市居民主要的游憩空间是近中距离的游憩度假地;可以划分为主要游憩空间和辅助性游憩空间;昆明城市居民的经济属性、年龄属性与居民的游憩活动空间具有相关性. 相似文献
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Z. Li H. Yan T. Ai J. Chen 《International journal of geographical information science》2013,27(5):513-534
Building generalization is a difficult operation due to the complexity of the spatial distribution of buildings and for reasons of spatial recognition. In this study, building generalization is decomposed into two steps, i.e. building grouping and generalization execution. The neighbourhood model in urban morphology provides global constraints for guiding the global partitioning of building sets on the whole map by means of roads and rivers, by which enclaves, blocks, superblocks or neighbourhoods are formed; whereas the local constraints from Gestalt principles provide criteria for the further grouping of enclaves, blocks, superblocks and/or neighbourhoods. In the grouping process, graph theory, Delaunay triangulation and the Voronoi diagram are employed as supporting techniques. After grouping, some useful information, such as the sum of the building's area, the mean separation and the standard deviation of the separation of buildings, is attached to each group. By means of the attached information, an appropriate operation is selected to generalize the corresponding groups. Indeed, the methodology described brings together a number of well-developed theories/techniques, including graph theory, Delaunay triangulation, the Voronoi diagram, urban morphology and Gestalt theory, in such a way that multiscale products can be derived. 相似文献
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Xiang Zhang Jantien Stoter Tinghua Ai Menno-Jan Kraak Martien Molenaar 《International journal of geographical information science》2013,27(8):1550-1571
Evaluation is a key step to examine the quality of generalized maps with respect to map requirements. Map generalization facilitates the recognition of pattern generating processes by preserving and highlighting the patterns at smaller scales. This article focuses specifically on the evaluation of building patterns in topographic maps that are generalized from large to mid scales. Currently, there is a lack of knowledge and functionality on automatically evaluating how these patterns are generalized. The issues of the evaluation range from missing formal map requirements on building alignments to missing automated evaluation techniques. This article firstly analyses the requirements (constraints) related to the generalization of building alignments. Then, it focuses on three more specific constraints, i.e. on existence, orientation of alignments and spatial distribution of composing buildings. Later, a three-step approach is proposed to (1) recognize and (2) match alignments from source and generalized datasets and (3) evaluate building alignments in generalized datasets. Besides, many-to-many and partial matching between initial and target alignments is a side effect of generalization, which reduces the reliability of the evaluation results. This article introduces a confidence indicator to document the reliability and to inform intended users (e.g. cartographers) and/or systems about the reliability of evaluation decisions. The effectiveness of our approach is demonstrated by evaluating the alignments in both interactively (manually) generalized maps and automated generalized maps. Finally, we discuss how our approach can be used to control automated generalization and identify further improvements. 相似文献
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Emmanuel Stefanakis 《International journal of geographical information science》2013,27(10):1826-1844
Linear features are represented on paper or digital maps with polyline geometries. Sampling, discretization, and generalization processes result in polylines of a length smaller than that of the actual features. In addition, semantics associated to the original line features may be lost. This becomes more significant for coarse sampling and/or high degree of generalization. This paper introduces a data structure that can alleviate this problem, by preserving the attributes and semantic characteristics associated to the original features in cartographic representation. The structure can handle both linear features and polygon outlines. Various compression methods have been examined. The structure has been implemented and tested with both synthetic and real datasets. Extensions to spatiotemporal features, like trajectories, have also been considered. 相似文献
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土地利用数据尺度转换的精度损失分析 总被引：10，自引：0，他引：10
由于栅格数据便于空间分析,因而通常将矢量数据转化成栅格数据来进行空间分析.在转化过程中,选用不同的栅格大小,其面积和精度损失是不同的.针对这个问题,以重庆市110万的土地利用矢量数据为例,探讨了不同栅格大小下,各种土地利用类型在转化过程的面积和精度损失.研究表明(1)栅格大小＜100m时,其精度损失均＜3.3%.(2)在1000m时,其精度损失达到50%以上的地类有湖泊、水库坑塘、滩地、农村居民点用地、工交建设用地、戈壁、裸岩石地、平原区旱地和坡度＞25°的旱地,这些地类的平均图斑大小均在＜51hm2.(3)在30m～1000m间,平均图斑大小＜82hm2的地类随着栅格的由小变大,其面积变得比实际面积小;平均图斑大小＞101hm2的地类中除高盖度的草地和河渠之外,却与此相反. 相似文献
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二维Delaunay三角网的任意点删除算法研究 总被引：1，自引：0，他引：1
针对目前基于影响域多边形剖分的点删除算法缺陷,提出一种二维Delaunay三角网点删除算法。首先利用具有拓扑关系的三角网搜索影响多边形,并以三角形矢量面积为工具三角剖分影响域多边形,最后通过镶嵌优化后的剖分三角网完成点的删除,且满足Delaunay法则。通过测试证明了算法的可靠性和高效性。 相似文献
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山地高密度城市热岛效应的多约束因子格局分析与定量探测——重庆都市区案例研究 总被引：1，自引：0，他引：1
城市热岛受城市地表多因素影响,山地城市的情况则更为复杂。本文以典型山地城市重庆为例,基于Landsat8 OLI/TIRS影像、高精度矢量建筑等多源空间数据,采用城市地温反演、归一化植被指数、天空开阔度建模等方法,重点针对城市建成区,通过地理探测器分析各因子对城市热岛效应的约束力。研究表明：① 在都市区全域,城市热场空间异质性显著,植被覆盖、城市表面高程和天空开阔度因子具有全局性约束力表现,建筑密度、容积率和路网距离具有局部约束力表现。② 在城市建成区内部,对城市热岛效应约束性排前三位因子分别为：植被覆盖（q=0.782）、城市表面高程（q=0.499）、建筑密度（q=0.496）;局部约束因子建筑密度、容积率和道路距离的约束力均较强,但三者差异小;天空开阔度对城市热岛的全局性影响相对较小（q<0.1）。③ 在城市建成区内部,各约束因子对城市热岛具有叠加约束效应,叠加解释度q（Xi∩Xj）均强于独立解释度,叠加q值介于0.50~0.82之间。 相似文献
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简单要素模型下多边形叠置分析算法 总被引：1，自引：0，他引：1
现有的矢量空间叠置分析多采用拓扑模型,要求建立完整的数据拓扑关系。该文采用简单要素模型,以多边形叠置交运算为例,介绍简单要素模型下空间叠置分析的具体实现,着重讨论多边形交运算的交替搜索算法,在线段求交中对连续出入点、重交点等特殊数据进行处理。在实际应用中,该算法可较好解决大规模复杂数据层的叠置交运算,比同规模的拓扑叠置运算效率高。 相似文献
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道路网络生态干扰测度指数的改进及其空间分异特征——以闽江上游为例 总被引：1，自引：1，他引：0
以闽江上游地区为例,在传统指数的基础上,提出并采用改进后的道路网络线密度和道路网络影响域面密度指数,结合空间自相关分析方法,从线上和面上综合探索道路网络对生态干扰的空间分异格局;并分析指数间的相关性。结果表明：① 道路干扰程度具有明显的地区差异,在研究区中部、东部和南部存在空间集聚效应;② 考虑到坡度影响,同等级的道路缓冲带宽度并不是一个固定值;③ 所有指数均呈显著正相关,同类指数相关性大,不同类指数相关性小。若仅采用单一的线密度或面密度指数,则将导致信息不全;虽然同类指数间相关性很大,相互印证,但改进后的指数更加符合客观事实,建议采用。 相似文献
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To fully understand forest resources, it is imperative to understand the social context in which the forests exist. A pivotal part of that context is the forest ownership. It is the owners, operating within biophysical and social constraints, who ultimately decide if the land will remain forested, how the resources will be used, and by whom. Forest ownership patterns vary substantially across the United States. These distributions are traditionally represented with tabular statistics that fail to capture the spatial patterns of ownership. Existing spatial products are not sufficient for many strategic-level planning needs because they are not electronically available for large areas (e.g., parcels maps) or do not provide detailed ownership categories (e.g., only depict private versus public ownership). Thiessen polygon, multinomial logit, and classification tree methods were tested for producing a forest ownership spatial dataset across four states with divergent ownership patterns: Alabama, Arizona, Michigan, and Oregon. Over 17,000 sample points with classified forest ownership, collected as part of the USDA Forest Service, Forest Inventory and Analysis (FIA) program, were divided into two datasets, one used as the dependent variable across all of the models and 10 percent of the points were retained for validation across the models. Additional model inputs included a polygon coverage of public lands from the Conservation Biology Institute’s Protected Areas Database (PAD) and data representing human population pressures, road densities, forest characteristics, land cover, and other attributes. The Thiessen polygon approach predicted ownership patterns based on proximity to the sample points in the model dataset and subsequent combining with the PAD ownership data layer. The multinomial logit and classification tree approaches predicted the ownership at the validation points based on the PAD ownership information and data representing human population, road, forest, land cover, and other attributes. The percentage of validation points across the four states correctly predicted ranged from 76.3 to 78.9 among the methods with corresponding weighted kappa values ranging from 0.73 to 0.76. Different methods performed slightly, but statistically significantly, better in different states Overall, the Thiessen polygon method was deemed preferable because: it has a lower bias towards dominant ownership categories; requires fewer inputs; and is simpler to implement. 相似文献