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When analyzing spatial issues, geographers are often confronted with many problems with regard to the imprecision of the available information. It is necessary to develop representation and design methods which are suited to imprecise spatiotemporal data. This led to the recent proposal of the F‐Perceptory approach. F‐Perceptory models fuzzy primitive geometries that are appropriate in representing homogeneous regions. However, the real world often contains cases that are much more complex, describing geographic features with composite structures such as a geometry aggregation or combination. From a conceptual point of view, these cases have not yet been managed with F‐Perceptory. This article proposes modeling fuzzy geographic objects with composite geometries, by extending the pictographic language of F‐Perceptory and its mapping to the Unified Modeling Language (UML) necessary to manage them in object/relational databases. Until now, the most commonly used object modeling tools have not considered imprecise data. The extended F‐Perceptory is implemented under a UML‐based modeling tool in order to support users in fuzzy conceptual data modeling. In addition, in order to properly define the related database design, an automatic derivation process is implemented to generate the fuzzy database model. 相似文献
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Seung-Hyun Jeong Norman W. Paton Alvaro A. A. Fernandes Tony Griffiths 《Transactions in GIS》2005,9(2):129-156
Many applications capture, or make use of, spatial data that changes over time. This requirement for effective and efficient spatio‐temporal data management has given rise to a range of research activities relating to spatio‐temporal data management. Such work has sought to understand, for example, the requirements of different categories of application, and the modelling facilities that are most effective for these applications. However, at present, there are few systems with fully integrated support for spatio‐temporal data, and thus developers must often construct custom solutions for their applications. Developers of both bespoke solutions and of generic spatio‐temporal platforms will often need to support the fusion of large spatio‐temporal data sets. Supporting such requests in a database setting involves the use of join operations with both spatial and temporal conditions – spatio‐temporal joins. However, there has been little work to date on spatio‐temporal join algorithms or their evaluation. This paper presents an evaluation of several approaches to the implementation of spatio‐temporal joins that build upon widely available indexing techniques. The evaluation explores how several algorithms perform for databases with different spatial and temporal characteristics, with a view to helping developers of generic infrastructures or custom solutions in the selection and development of appropriate spatio‐temporal join strategies. 相似文献
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Many applications, in areas such as land use, traffic management and location aware services, involve the storage, analysis and sharing of spatio‐temporal data. The need to represent such data in a way that eases sharing across applications, has led to the development of the Geography Markup Language (GML), which provides a rich collection of constructs for representing spatial and associated aspatial data as XML documents. However, although there are a growing number of applications and tools that make use of GML, there are surprisingly few experience reports on the representation of data from existing applications or models using GML constructs. This paper provides one such report, describing the use of GML as an exchange format for the Tripod spatio‐historical database. This in turn involves identifying mappings between Tripod and GML constructs, and the development of a generic architecture for carrying out such mappings. The experience demonstrates that even though GML provides rich modelling facilities, the development of mappings from pre‐existing models can be challenging, as related constructs often provide semantically distinct capabilities. 相似文献
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《制图学和地理信息科学》2013,40(4):180-195
Most existing spatial analytic techniques use a simplified, point-based representation of spatial objects. This facilitates tractability of the standard computational procedures for many spatial measures, for example, distances between spatial objects. The increasing spatial data handling and manipulation capabilities of geographic information systems (GIS), however, allow a re-examination of fundamental representations and measures in spatial analysis. This article develops exact computational procedures for calculating the average, minimum, and maximum distances between pairings of the three geometric primitives (points, lines, and polygons) when these objects are stored in the vector GIS data model. These procedures are “exact” in the sense that they are completely accurate, subject to the database representation. This article also provides example results from average distance calculations for a generic spatial database. 相似文献
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The integration of distributed geospatial data is a great issue in GI Science. Hereby, the collection of data from different systems and different structures as well as across country borders is a problem. We explain a model‐based four‐step approach to conceptual data modelling. Within this approach, we introduce a methodology to map data models on the conceptual level without touching data formats. First, we developed a conceptual mapping language called “UMLT” which is the core of our approach. Furthermore, we integrated UMLT into the Model‐Driven Architecture where a conceptual model mapping is referred to as a platform independent model mapping. Finally, the data format transformation is deduced from the model mapping automatically. This represents the implementation mapping from a platform independent model to a platform specific model. Together with transformation operations for attribute mapping, this approach is a means for effective and enhanced semantic interoperability. 相似文献
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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
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针对空间数据动态更新的冲突检测与处理问题,以空间冲突的表现形式为基础,以地理实体与数据库空间目标的映射关系为切入点,探讨了空间冲突的检测方法,给出了空间冲突检测模型;并综合考虑不同类型的空间冲突,针对性地给出了处理方案;最后通过自主开发的更新系统进行实例验证,取得了良好的实验结果,证实了该方法具有一定的可靠性。 相似文献
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Synchronous geocollaboration helps geographically dispersed people to work together in a shared geospatial environment. Its real‐time nature, multiple users' interaction and diversity of work context impose some special social, organizational and technological requirements, making the development of such real‐time geocollaboration systems a challenging task. A conceptual framework is therefore needed to specify and describe what synchronous geocollaboration is, considering its social, spatial and technical aspects. The geo‐social model presented in this article describes a conceptual framework for synchronous geocollaboration systems addressing the above aspects, identifies the core elements of the system and describes how these elements collaborate with each other. This model is presented using application‐level ontology and is then applied to a multi‐agent system based prototype in which multiple users can interact and negotiate in a shared 3D geospatial environment. 相似文献
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在GIS应用中,涉及到大量的模型应用,这些模型包括了利用GIS进行空间信息处理的大部分阶段中所用到的模型.模型处理以及分析结果往往是进行下一步应用的基础,因此模型处理结果的误差和不确定性制约了实际的GIS应用.影响空间数据处理模型的误差和不确定性的因素主要包括:定位和特征信息,制图,空间分析,空间数据库以及空间数据处理模型等所具有的误差和不确定性.主要分析了空间数据处理模型误差和不确定性的表达、来源以及分析方法. 相似文献
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Alan Glennon 《Transactions in GIS》2010,14(1):23-42
Object-oriented geographic data models provide an organizational scheme to associate domain specific meaning to primitive GIS elements like points, polylines, and polygons. Although use of data models is widespread in the GIS community, the design process is not necessarily obvious and often ad hoc. This article outlines a procedure for the creation and validation of geographic data models through the examination and distillation of use cases. As an example, the article follows the development of a data model for the spatial concept of flow. Flow, the collective movements of people, materials, or ideas, is a common driver of geographic change, not generally supported by functionality within contemporary GIS, and an abstract dynamic entity that would presumably be difficult to model. Model design was facilitated through the distillation of flow cases of tabular human migration data, Minard's map of Napoleon's march on Moscow, and stream channel routes in a karst watershed. Unified Modeling Language diagrams are created for each case and the models' commonalities combined to yield a generic data model. As a means of validation, each use case was instantiated with the generic model and tested to re-create the fundamental components of flow and address predefined typical queries. 相似文献
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Edzer J Pebesma 《Transactions in GIS》2006,10(4):615-632
Although many geostatistical studies only study a measured attribute in relation to its spatial coordinates, this paper argues that other layers in the GIS database can be of additional use for spatial prediction purposes. They may enter the prediction equations as predictors in a regression model, or as correlated measurements. In an example we will show how this is done for predicting PCB138, a sediment pollution variable, over the North Sea floor. Issues of exploratory data analysis, required sample size, sample configuration, local versus global neighbourhoods, non‐stationarity, non‐linear transformations, change of support and conditional simulation will be discussed in the light of this example. 相似文献
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KAREN K KEMP 《Transactions in GIS》1996,1(3):219-234
Linking a GIS to a spatially distributed, physically-based environmental model offers many advantages. However, the implementation of such linkages is generally problematic. Many problems arise because the relationship between the reality being represented by the mathematical model and the data model used to organize the spatial data in the GIS has not been rigorously defined. In particular, while many environmental models are based on theories that assume continuity and incorporate physical fields as independent variables, current GISs can only represent continuous phenomena in a variety of discrete data models. This paper outlines a strategy in which field variables are used to enable modellers to work directly with the spatial data as spatially continuous phenomena. This allows the manner in which the spatial data has been discretized and the ways in which it can be manipulated to be treated independently from the conceptual modelling of physical processes. Modellers can express their spatial data needs as representations of reality, rather than as elements of a GIS database, and a GIS-independent language for model development may result. By providing a formal linkage between the various models of spatial phenomena, a mechanism is created for the explicit expression of transformation rules between the different spatial data models stored and manipulated by a GIS. 相似文献
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MASTER: A multiple aspect view on trajectories 总被引：1，自引：0，他引：1
Ronaldo dos Santos Mello Vania Bogorny Luis Otavio Alvares Luiz Henrique Zambom Santana Carlos Andres Ferrero Angelo Augusto Frozza Geomar Andre Schreiner Chiara Renso 《Transactions in GIS》2019,23(4):805-822
For many years trajectory data have been treated as sequences of space‐time points or stops and moves. However, with the explosion of the Internet of Things and the flood of big data generated on the Internet, such as weather channels and social network interactions, which can be used to enrich mobility data, trajectories become more and more complex, with multiple and heterogeneous data dimensions. The main challenge is how to integrate all this information with trajectories. In this article we introduce a new concept of trajectory, called multiple aspect trajectory, propose a robust conceptual and logical data model that supports a vast range of applications, and, differently from state‐of‐the‐art methods, we propose a storage solution for efficient multiple aspect trajectory queries. The main strength of our data model is the combination of simplicity and expressive power to represent heterogeneous aspects, ranging from simple labels to complex objects. We evaluate the proposed model in a tourism scenario and compare its query performance against the state‐of‐the‐art spatio‐temporal database SECONDO extension for symbolic trajectories. 相似文献
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A Review of Sampling Effects and Response Bias in Internet Participatory Mapping (PPGIS/PGIS/VGI) 
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下载免费PDF全文 Greg Brown 《Transactions in GIS》2017,21(1):39-56
Global interest in participatory mapping described as public participation GIS (PPGIS), participatory GIS (PGIS), and volunteered geographic information (VGI) continues to grow, but systematic study of spatial data quality and sampling effects is limited. This article provides a review and meta‐analysis of Internet‐based PPGIS studies conducted during the period 2006–2015 (n=26) to answer the following research questions: (1) How does mapping effort, as a proxy measure for spatial data quality, differ by sampling group? (2) Does the purpose and context of PPGIS influence mapping results? (3) What is the potential for mapping bias through sampling design? (4) Given the results, what should be the focus of future PPGIS research? Mapping effort was highest in sampling groups whose livelihoods were closely related to the purpose of the study, there was greater mapping effort in household sampling groups compared to volunteer groups, and participant domicile had strong effects on mapped results through spatial discounting. The use of online Internet panels provides higher response rates but lower spatial data quality. Future research should focus on increasing sampling response rates, assessing social trade‐offs using alternative spatial weighting schemes, and examining the capacity of the public to select land use alternatives as a complement to traditional expert‐driven planning systems. 相似文献
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Geographic features change over time, this change being the result of some kind of event. Most database systems used in GIS are relational in nature, capturing change by exhaustively storing all versions of data, or updates replace previous versions. This stems from the inherent difficulty of modelling geographic objects and associated data in relational tables, and this is compounded when the necessary time dimension is introduced to represent how these objects evolve. This article describes an object‐oriented (OO) spatio‐temporal conceptual data model called the Feature Evolution Model (FEM), which can be used for the development of a spatio‐temporal database management system (STDBMS). Object versioning techniques developed in the fields of Computer Aided Design (CAD) and engineering design are utilized in the design. The model is defined using the Unified Modelling Language (UML), and exploits the expressiveness of OO technology by representing both geographic entities and events as objects. Further, the model overcomes the limitations inherent in relational approaches in representing aggregation of objects to form more complex, compound objects. A management object called the evolved feature maintains a temporally ordered list of references to features thus representing their evolution. The model is demonstrated by its application to road network data. 相似文献
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UML和象形图建立GIS数据库概念模型初探 总被引：2，自引：0，他引：2
空间数据库模型的构建是地理信息系统应用的基础,传统的地理信息数据库在管理机制、时间维的加入、对空间数据多尺度的表达等多方面存在问题,要解决这些问题就必须从建立可行的数据库概念模型开始研究。本文论述了为什么用UML和象形图可以解决这些问题,详细地说明了用这种方法建模的过程,并用一个实例来证明这种方法的可用性。 相似文献
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ArcSDE作为空间数据引擎,在地理信息系统中有着广泛的应用,它能有效的提高空间数据库的管理效率。本文在对常用空间数据引擎比较的基础上,根据信息基础设施空间数据种类多、数据量大的特点,提出了基于ArcSDE SQL Server 2000技术构建的信息基础设施空间数据库建设方案,实现了海量数据的空间存储和有效管理,有利于信息的共享和充分利用,并在实际应用中取得了很好的效果。 相似文献