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1.
Qualitative representation of spatial locations and their similarity measurements are essential for the analysis of linguistic term‐based data. Existing methods have focused on the similarities of spatial relations and spatial scenes but have not considered the variations in geometrical representations and relations over scales. This study developed some new measures to assess the similarities of both single‐ and multi‐scale qualitative locations. Region‐ and cell‐based models were used to formalize qualitative locations of spatial objects with respect to multi‐scale frames of reference. The similarities were assessed by integrating the similarities of frames and qualitative relations. The frame similarity measures how two objects are compared considering the common elements that they occupy in the reference frames. Moreover, the similarity of qualitative relation measures how two relations relate two objects to the corresponding elements in the frames. The location similarities at a single level integrate the similarities of the frames and qualitative relations, whereas the location similarities at multiple scales incorporate the variations in qualitative locations over scales. These methods were used to assess location similarities concerning residential areas, roads, and lakes. The results indicated that the location‐based measurements can disclose the distributions of the similarities and that the cell‐based model is more accurate than the region‐based model. 相似文献
2.
Miriam Baglioni Emiliano Giovannetti Maria Vittoria Masserotti Chiara Renso Laura Spinsanti 《Transactions in GIS》2008,12(Z1):31-44
Querying geographical information systems has been recognized as a difficult task for non‐expert users. Furthermore, user queries are often characterized by semantic aspects not directly managed by traditional spatial databases or GIS. Examples of such semantic geospatial queries are the use of implicit spatial relations between objects, or the reference of domain concepts not explicitly represented in data. To handle such queries, we envisage a system that translates natural language queries into spatial SQL statements on a database, thus improving standard GIS with new semantic capabilities. Within this general objective, the contribution of this article is to introduce a methodology to handle semantic geospatial queries issued over a spatial database. This approach captures semantics from an ontology built upon the spatial database and enriched by domain concepts and properties specifically defined to represent the localization of objects. Some examples of the use of the methodology in the urban domain are presented. 相似文献
3.
相似性度量是地理学中的关键组成部分,被广泛应用于空间检索、空间信息整合及空间数据挖掘中。因为空间场景中实体个数的差异及空间对象间的关系难以精确相等,若执行空间场景的完全精确匹配,可能会使得检索结果为空。顾及尺度差异,从空间场景中进行空间语义理解,建立了多尺度空间场景的形式化描述模型,并提取场景中稳定的特征构建空间场景特征矩阵。建立场景间的初始匹配概率矩阵后,基于松弛标记法迭代更新概率矩阵,直到矩阵收敛于一全局最小值并确定匹配的实体对,从而进行空间场景相似性评估。采用武汉居民地域数据进行场景匹配实验,并对不同邻域搜索半径下的匹配时间及精确度进行对比与分析,实验结果表明,基于松弛标记法的空间场景匹配方法具有较高的精确度。 相似文献
4.
本文主要结合目前城市社区发展的特点,利用社区相关的空间数据和属性数据,实现数字社区的三维显示和相关信息的实时查询:研究了如何将原始矢量图形数据转换到ARCGIS中,以及如何利用三维建模软件和GIS软件相结合来建模,最终在ArcScene场景中实现三维场景的显示及信息的查询。 相似文献
5.
Spatial signatures for geographic feature types: examining gazetteer ontologies using spatial statistics 总被引：1，自引：0，他引：1 
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下载免费PDF全文 Digital gazetteers play a key role in modern information systems and infrastructures. They facilitate (spatial) search, deliver contextual information to recommended systems, enrich textual information with geographical references, and provide stable identifiers to interlink actors, events, and objects by the places they interact with. Hence, it is unsurprising that gazetteers, such as GeoNames, are among the most densely interlinked hubs on the Web of Linked Data. A wide variety of digital gazetteers have been developed over the years to serve different communities and needs. These gazetteers differ in their overall coverage, underlying data sources, provided functionality, and geographic feature type ontologies. Consequently, place types that share a common name may differ substantially between gazetteers, whereas types labeled differently may, in fact, specify the same or similar places. This makes data integration and federated queries challenging, if not impossible. To further complicate the situation, most popular and widely adopted geo‐ontologies are lightweight and thus under‐specific to a degree where their alignment and matching become nothing more than educated guesses. The most promising approach to addressing this problem, and thereby enabling the meaningful integration of gazetteer data across feature types, seems to be a combination of top‐down knowledge representation with bottom‐up data‐driven techniques such as feature engineering and machine learning. In this work, we propose to derive indicative spatial signatures for geographic feature types by using spatial statistics. We discuss how to create such signatures by feature engineering and demonstrate how the signatures can be applied to better understand the differences and commonalities of three major gazetteers, namely DBpedia Places, GeoNames, and TGN. 相似文献
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Rule-Based Discovery in Spatial Data Infrastructure 总被引：2，自引：0，他引：2
7.
Yujia Xie Meizhen Wang Xuejun Liu Ziran Wang Bo Mao Feiyue Wang Xiaozhi Wang 《Transactions in GIS》2021,25(1):450-467
Current studies on video trajectory retrieval focus on the retrieval and analysis of image content, neglecting the gap between the spatiotemporal continuity of retrieval conditions and the spatiotemporal discontinuity of multi‐camera video trajectories. In this study, we propose a method for the spatiotemporal retrieval of dynamic video object trajectories in geographic scenes. Based on the camera calibration, the proposed method organizes the scene, cameras, and trajectories, constructs the spatiotemporal constraints, and queries the trajectories using two measures: camera‐by‐camera retrieval and global trajectory retrieval. The proposed method was verified through experiments, and the results demonstrate that both measures can query trajectories effectively and reduce the spatiotemporal video review range under different spatiotemporal constraints. Furthermore, compared with camera‐by‐camera retrieval, global trajectory retrieval can reduce the spatiotemporal video review range further and return more accurate results. The proposed method may provide support for the spatial analysis and understanding of surveillance video data. 相似文献
8.
在虚拟地理空间中开展复杂科学实验和管理分析,是目前及未来发展的一个重要趋势。本文对高速铁路场景中的线路、地物和地形对象的关系进行了详细分析,提出了基于空间关系描述的虚拟高速铁路场景建模方法。通过XML标记语言对线路、地物和地形的空间关系进行统一描述,引导和规范场景建模过程中的模型点位计算和地形处理过程。详细讨论了虚拟高速铁路的场景建模流程、场景对象空间关系定义、模型点位计算方法以及地形处理方法,并选择案例区域进行试验。试验结果表明该方法能够有效地理清虚拟场景中各种对象间的关系,从而可以快速建设符合现实标准的、具有高度仿真感觉的虚拟高速铁路场景。 相似文献
9.
针对无人机视频巡查时无法获取视频要素与周围场景地理要素的空间关系等问题,本文提出了一种无人机实时视频与三维地理场景融合方法。该方法通过设置路线站点获取无人机实时巡查视频,利用高分辨率倾斜摄影模型构建三维地理场景,将视频在三维地理场景中投影,构建视频投影参数规范和无人机数据传输模型,实现无人机实时视频与三维地理场景融合展示;对无人机实景融合的应用流程进行设计,并通过具体案例进行试验验证。试验结果表明,无人机实景融合具有良好的表达效果,视频与三维地理场景融合度高且视频画面变形较小。该方法将无人机视频应用扩展至三维空间,为视频要素赋予了空间参考。 相似文献
10.
随着空间信息网格的建设,网格平台上管理的空间信息资源越来越丰富,这促进了空间信息网格中空间数据分布式查询的应用需求,而在分布式空间查询中,空间连接查询操作往往成为性能的瓶颈.根据空间信息的特点,通过利用网格计算资源来优化空间连接查询的执行.首先基于网格服务构建网格平台分布式空间数据查询软件结构,通过设计远程空间连接执行服务利用网格平台中的计算资源;根据空间信息的特点.采用基于Kd-Tree空间分区并行连接的方法提高远程空间数据连接操作执行效率,并给出了远程空间连接执行的查询代价模型;然后根据连接代价模型设计了远程空间连接查询执行计划优化生成算法;最后总结了本文工作并探讨了下一步研究方向. 相似文献
11.
A methodology is proposed for modelling spatially varying predictor effects on a disease or mortality count outcome. The methodology may be extended to multivariate outcomes, so that one may assess the similarity of spatial patterning of regression effects between outcomes. Another extension involves longitudinal data, where a number of modelling structures are possible. The methodology is illustrated by suicide mortality in 32 London Boroughs over the period 1979–1993, in terms of area deprivation and a measure of social fragmentation. 相似文献
12.
Jacek Kozak Christine Estreguil Katarzyna Ostapowicz 《International Journal of Applied Earth Observation and Geoinformation》2008
The aim of the study was to elaborate a methodology for forest mapping based on high resolution satellite data, relevant for reporting on forest cover and spatial pattern changes in Europe. The Carpathians were selected as a case study area and mapped using 24 Landsat scenes, processed independently with a supervised approach combining image segmentation, knowledge-based rules to extract a training set and the maximum likelihood decision rule. Validation was done with available very high resolution imagery. Overall accuracies per scene ranged from 93 to 96%. The labelling disagreement in overlapping areas of adjacent scenes was 6.8% on average. 相似文献
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14.
朱敏茹 《测绘与空间地理信息》2021,44(1):165-166,169,172
主要研究实现多尺度、多分辨率、不同时期、海量影像数据的快速加载,通过建立域地理三维演示系统,整合了三维模型场景数据、DEM、DOM等数据,实现了直观的全空间三维可视化、海量多元数据集成逼真的三维场景显示的特性、快捷的二三维一体化应用、高效的三维模型渲染与分析、矢量和影像文件的客户端直接加载,实现了城市DEM和DOM的快... 相似文献
15.
Dave Kolas 《Transactions in GIS》2008,12(Z1):5-18
Though the intersection of spatial data and semantic web technologies holds significant promise, there are still many challenges before this promise can be realized. One of these challenges is query representation. History suggests that an appropriate solution is a specialized query language for spatial data; however, with a broad interpretation of the SPARQL specification and extensions that would be useful outside the spatial realm, one can use SPARQL to query spatial concepts effectively. This article establishes a set of desiderata for a query language capable of dealing with spatial Semantic Web‐based data, discusses the challenges facing such a query language, and addresses these challenges with straightforward solutions that are broadly applicable. The effectiveness of these extensions is demonstrated using example queries. 相似文献
16.
针对传统高分辨率遥感影像场景变化检测流程复杂且严重依赖分类结果的问题,本文提出了一种顾及场景全局与局部相似性的变化检测方法。首先,将同一区域两个时相的遥感影像裁切成固定尺寸的图像块,构造场景对图像库,并划分为训练集和测试集;其次,构建融合场景全局与局部相似性的双分支卷积神经网络,实现场景相似度学习;然后,利用训练的相似度学习网络提取训练集场景相似度,并通过阈值遍历的方法得到最佳的相似度阈值;最后,基于相似度阈值将测试集场景对划分为变化场景和未变化场景,得到最终的变化检测结果。试验结果表明,本文方法的总体精度为0.94,Kappa系数为0.88,优于传统的分类后变化检测方法,是一种简单有效的场景变化检测方法。 相似文献
17.
精准空间划分是实现室内语义建模与拓扑结构重建的重要基础。三维点云作为常用的室内空间数据载体,如何基于三维点云进行室内空间语义信息提取与规则化具有重要意义。本文提出了一种基于形态学分割方法实现室内场景的分割,并结合矢量规则化方法完成分割场景的规则化。首先,基于区域增长算法与线性拟合方法提取空间分割要素,通过平面投影生成二进制影像,进而利用距离变换和分水岭算法完成空间分割;然后,对空间分割要素进行线性拟合,进行室内空间格网划分,采用矢栅叠加方法实现空间要素规则化;最后,通过4组实际场景(包含3组ISPRS数据集及1组实际场景采集数据)进行数据验证。试验结果显示,本文提出的室内空间分割与规则化方法可以准确快速地完成室内空间要素的提取。 相似文献
18.
《International Journal of Digital Earth》2013,6(2):175-206
ABSTRACTGlobal or regional land cover change on a decadal time scale can be studied at a high level of detail using the availability of remote sensing data such as that provided by Landsat. However, there are three main technical challenges in this goal. First, the generation of land cover maps without reference data is problematic (backdating). Second, it is important to maintain high accuracies in land cover change map products, requiring a reasonably rich legend within each map. Third, a high level of automation is necessary to aid the management of large volumes of data. This paper describes a robust methodology for processing time series of satellite data over large spatial areas. The methodology includes a retrospective analysis used for the generation of training and test data for historical periods lacking reference information. This methodology was developed in the context of research on global change in the Iberian Peninsula. In this study we selected two scenes covering geographic regions that are representative of the Iberian Peninsula. For each scene, we present the results of two classifications (1985–1989 and 2000–2004 quinquennia), each with a legend of 13 categories. An overall accuracy of over 92% was obtained for all 4 maps. 相似文献
19.
研究影响寻路行为的人为因素,对于提升智能导航服务的用户体验具有重要意义。从心理旋转、抽象推理、空间短时记忆和空间感知4种能力出发,设计空间认知对照实验,探究空间认知能力与寻路绩效之间的相关性。研究结果表明：（1）4种空间认知能力之间弱相关,且按空间尺度部分分离。相同尺度空间的认知能力,即心理旋转能力和抽象推理能力、短时记忆能力和空间感知能力的相关性较强,不同尺度空间的认知能力相关性较弱。（2）心理旋转能力和抽象推理能力对寻路绩效有较高的拟合显著性水平。考虑多因素联合作用,虚拟场景中,心理旋转能力对寻路绩效影响最大,空间感知能力影响最小;真实场景中,空间感知能力对寻路绩效影响最大,短时记忆能力影响最小。（3）寻路表现具有显著的场景效应,在虚拟和真实场景中各项能力因子对寻路绩效拟合的决定系数明显不同。该研究结果为基于虚拟场景的行人导航研究的有效性提供了实证参考,也可为设计顾及人因的导航服务提供依据。 相似文献
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FENGYucai YIBaolin 《地球空间信息科学学报》2004,7(4):297-302
Direction is a common spatial concept that is used in our daily life. It is frequently used as a selection condition in spatial queries. As a result, it is important for spatial databases to provide a mechanism for modeling and processing direction queries and reasoning. Depending on the direction relation matrix, an inverted direction relation matrix and the concept of direction pre- dominance are proposed to improve the detection of direction relation between objects. Direction predicates of spatial systems are also extended. These techniques can improve the veracity of direction queries and reasoning. Experiments show excellent efficiency and performance in view of direction queries. 相似文献