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1.
Visual data mining of spatial data is a challenging task. As exploratory analysis is fundamental, it is beneficial to explore the data using different potential visualisations. In this article, we propose and analyse network graphs as a useful visualisation tool to mine spatial data. Due to their ability to represent complex systems of relationships in a visually insightful and intuitive way, network graphs offer a rich structure that has been recognised in many fields as a powerful visual representation. However, they have not been sufficiently exploited in spatial data mining, where they have principally been used on data that come with an explicit pre-specified network graph structure. This research presents a methodology with which to infer relationship network graphs for large collections of boolean spatial features. The methodology consists of four principal stages: (1) define a co-location model, (2) select the type of co-association of interest, (3) compute statistical diagnostics for these co-associations and (4) construct and visualise a network graph of the statistic from step (3). We illustrate the potential usefulness of the methodology using an example taken from an ecological setting. Specifically, we use network graphs to understand and analyse the potential interactions between potential vector and reservoir species that enable the propagation of leishmaniasis, a disease transmitted by the bite of sandflies.  相似文献   

2.
GIS elemental unit representations of spatial data are often defined in terms of points, lines and areas. However, another type of spatial data that is becoming frequently captured, but as yet is largely ignored in GIS, is that of video. While digital video recording is a commonly encountered medium in modern society and encompasses many forms, from simple personal camcorders through to sophisticated survey and surveillance systems, its geographical representation in a GIS has not been fully examined or realised. In the majority of cases the video footage is usually captured while the device and/or the objects being viewed are in motion. What is of particular interest is when video streams can be, or have been, associated with spatial data such as location and orientation to create geographically referenced videographic data, which, for simplicity, will be defined as spatial video. Fundamentally, the nature of video is to record space, so when spatial properties can be accurately acquired and associated with this footage, an important geographical element can be considered for integration and analysis within a GIS.

Existing spatial video systems, both commercial and research, are predominantly used in survey or LBS roles and are usually bespoke and application specific. These systems do not model spatial video to any recognised standards that is generalised to be both data and platform independent. They do not support GIS integration and/or analysis from a purely spatial content perspective. A video-image/remote-sensing centric approach prevails where usage options range from simple visualisation interfaces to interactive computer vision systems. What has been largely overlooked is a spatial approach where the inherent geographical extent recorded in each video frame can be modelled and used in a geo-spatial analysis context. While this modelling approach has not been fully realised, it does exist in a GIS form based on Open Geospatial Consortium standards, where the spatial context of video is defined in a structure called a ViewCone. However, a ViewCone only defines a 2D model of the geographical extent of each frame and is restricted to a three-or-five sided polygon representation.

Thus, this article examines the potential of modelling spatial video through the use of elemental data types within GIS; gives some examples of using this approach; describes some problems in using spatial video within GIS; and then demonstrates how these problems are being solved. This is done in three stages: Firstly, a detailed overview of spatial video in its current GIS role is provided – this is achieved through a complete introduction to the distinct elements of spatial video followed by a review of its use in both commercial and academic application areas. Secondly, a brief theoretical overview of an alternative GIS-constrained ViewCone data structure is given that defines a more flexible spatial video model for both 2D and 3D GIS analysis and visualisation. Thirdly, a selective sample of results is presented based on an implementation of this approach being applied to a constrained spatial video data source in a specific study area.  相似文献   

3.

Cartographic visualisation tools aid exploration, but they are designed for, and used exclusively by, experts. A democratised visualisation tool will include second-generation users, and these non-specialists might also want to use the available computer technology to visualise their geographical data. In this paper, we argue that democratised GIS should have a functionality similar to visualisation tools and we forward our opinion on how these can be developed in order to do so. Our emphasis is on interactivity regarding representation methods and on elaborating principles for implementing map type selection in interfaces for democratised GISs.  相似文献   

4.
Abstract

Remotely-sensed image data have long served as a primary source of information for. geographical information systems (GIS), with the transformation of data to information provided by visual image interpretation. Digital image data, in combination with recent advances in computer technology, currently allow visual image interpretation to be realised in a completely digital processing environment. However, it remains desirable to capitalize even further on the potential of digital image data for GIS, through the use of schemes involving automated data processing. The opportunities for, and impediments to, such schemes are considered here with particular reference to the provision of information for natural resource management. It is concluded that further—although foreseeable—developments in both research and technology will be required before fully operational procedures for the automated acquisition of GIS information from image data can be established.  相似文献   

5.
Data modelling is a critical stage of database design. Recent research has focused upon object-oriented data models, which appear more appropriate for certain applications than either the traditional relational model or the entity-relationship approach. The object-oriented approach has proved to be especially fruitful in application areas, such as the design of geographical information systems which have a richly structured knowledge domain and are associated with multimedia databases. This article discusses the key concepts in object-oriented modelling and demonstrates the applicability of an object-oriented design methodology to the design of geographical information systems. In order to show more clearly how this methodology may be applied, the paper considers the specific object-oriented data model IFO. Standard cartographic primitives are represented using IFO, which are then used in the modelling of some standard administrative units in the United Kingdom. The paper concludes by discussing current research issues and directions in this area.  相似文献   

6.
Cephalopod stocks are of increasing economic importance. Cephalopod fisheries show marked inter-annual fluctuations unrelated to fishery landings and effort. Their population dynamics, particularly recruitment, are thought to be strongly susceptible to changes in environmental conditions. This arises in part from the short life cycle, resulting in poor buffering of the population against changing conditions. These characteristics make traditional approaches to stock assessment and fishery management inappropriate. GIS offers a tool to improve understanding of spatio-temporal trends in abundance and facilitate rational management. A cephalopod fishery geographical information system for Northeast Atlantic waters (CFGIS-NEA) was developed. The system covers the area from 28.0° W to 11.0° E, and 34.5° N to 65.5° N. It was designed for investigating cephalopod resource dynamics in relation to environmental variation. It is based on Unix Arc/Info, and PC ArcView, combined with the statistical software package S-PLUS and supported by a database in Microsoft Access. Environmental data (e.g. sea surface temperature and salinity, sea bottom temperature and salinity, and bathymetric data), cephalopod fishery, survey and biological data, from a variety of sources, were integrated in the GIS as coverages, grids, shapefiles, and tables. Special functions were developed for data integration, data conversion, query, visualisation, analysis and management. User-friendly interfaces were developed allowing relatively inexperienced users to operate the system. The spatial and temporal distribution patterns of cephalopod abundance by species, the spatial and temporal relationships between cephalopod abundance and environmental factors, and the spatial and temporal patterns of cephalopod fishing activity were analysed using a combination of visual (qualitative) and quantitative methods. Predictive empirical models, such as GAMs (generalized additive models), were developed for modelling cephalopod abundance using environmental variables.  相似文献   

7.
Web2.0环境为网民提供了线上产消（即网络文化生产与消费相结合）的平台,其产消结果为地理想象研究提供了新素材。研究基于地理想象的相关理论,以百度贴吧“波兰球吧”为案例,通过对网络漫画“波兰球”进行内容分析,并对“波兰球吧”用户展开结构化访谈,探讨线上产消者在“波兰球”漫画中建构的全球地理想象特征及其机制。研究认为：产消者通过“波兰球”漫画表征世界地理,建构了关于全球地缘关系的“中心-边缘”结构的地理想象;产消者基于中国的本土视角在漫画中建构世界各国（地区）的地理想象;产消者在“波兰球”漫画中的地理想象建构机制是一种基于互动的产消实践。  相似文献   

8.
Forecasting dust storms for large geographical areas with high resolution poses great challenges for scientific and computational research. Limitations of computing power and the scalability of parallel systems preclude an immediate solution to such challenges. This article reports our research on using adaptively coupled models to resolve the computational challenges and enable the computability of dust storm forecasting by dividing the large geographical domain into multiple subdomains based on spatiotemporal distributions of the dust storm. A dust storm model (Eta-8bin) performs a quick forecasting with low resolution (22 km) to identify potential hotspots with high dust concentration. A finer model, non-hydrostatic mesoscale model (NMM-dust) performs high-resolution (3 km) forecasting over the much smaller hotspots in parallel to reduce computational requirements and computing time. We also adopted spatiotemporal principles among computing resources and subdomains to optimize parallel systems and improve the performance of high-resolution NMM-dust model. This research enabled the computability of high-resolution, large-area dust storm forecasting using the adaptively coupled execution of the two models Eta-8bin and NMM-dust.  相似文献   

9.
It is challenging to find relevant data for research and development purposes in the geospatial big data era. One long-standing problem in data discovery is locating, assimilating and utilizing the semantic context for a given query. Most research in the geospatial domain has approached this problem in one of two ways: building a domain-specific ontology manually or discovering automatically, semantic relationships using metadata and machine learning techniques. The former relies on rich expert knowledge but is static, costly and labor intensive, whereas the second is automatic and prone to noise. An emerging trend in information science takes advantage of large-scale user search histories, which are dynamic but subject to user- and crawler-generated noise. Leveraging the benefits of these three approaches and avoiding their weaknesses, a novel methodology is proposed to (1) discover vocabulary-based semantic relationships from user search histories and clickstreams, (2) refine the similarity calculation methods from existing ontologies and (3) integrate the results of ontology, metadata, user search history and clickstream analysis to better determine their semantic relationships. An accuracy assessment by domain experts for the similarity values indicates an 83% overall accuracy for the top 10 related terms over randomly selected sample queries. This research functions as an example for building vocabulary-based semantic relationships for different geographical domains to improve various aspects of data discovery, including the accuracy of the vocabulary relationships of commonly used search terms.  相似文献   

10.
The presence of uncertainty in geographical data has the potential to expose users to undesirable consequences in their decision making. Accordingly, our efforts to understand uncertainty seek to (a) avoid the use of data that are not suitable for their intended purpose (that is, data whose consequences are unacceptable), (b) to reduce any undesirable consequences to an acceptable level, and (c) to devise ways of living with undesirable data when the adverse consequences caused by poor data do not alter our ultimate decision choice. To assist this task, we propose an approach where the adverse consequences of uncertainty caused by the use of unsuitable geographical data are expressed in terms of risk. In this paper we first show that risk management offers geographical data users a range of options for responding to the adverse consequences of data uncertainty, and secondly we present and discuss the various risk response options.  相似文献   

11.
William Bunge's Fitzgerald: Portrait of a Revolution, initially published in 1971, is an enthralling verbal and visual account of the historical and geographical development of a one-square-mile neighborhood in Detroit. The original analysis of the Fitzgerald neighborhood was based on intensive field-based research conducted in a theoretical context of race and racism. The research reported here maintains that context but updates Fitzgerald's account of the neighborhood's built environment through a spatial analysis that uses parcel-by-parcel data generated in Google Earth and Google Street View instead of data collected in the field. Current spatial patterns of deterioration in the built environment are similar to those described in Fitzgerald, but positive sites are also apparent and often colocated with negative ones.  相似文献   

12.
It has been recently recognized that fuzzy set theory provides useful concepts and tools for both the representation and analysis of the uncertainty related to geographical data. Hence the incorporation of fuzzy set methodologies into a DBMS repository for the application domain of GIS should be beneficial and will improve its level of intelligence. Focusing in this area the paper addresses both a representation and a reasoning issue. Specifically, it extends a general spatial data model to deal with the uncertainty of geographical entities, and shows how the standard data interpretation operations available in GIS packages may be extended to support the fuzzy spatial reasoning. Representative geographical operations, suchas the fuzzy overlay, fuzzy distance and fuzzy select, are examined, while several real world examples are given.  相似文献   

13.
在基于时间片的连续快照模型基础上,基于OpenGIS定义的几何类型扩充了时态类型,构建面向对象的时空数据模型,定义其抽象数据类型及相关操作;并采用对象关系数据库PostgreSQL作为实现平台,扩展其存储和查询能力。通过实例验证了上述模型及实现方法的有效性和实用性。  相似文献   

14.
数字地形模型数据产品特点 与评估分析   总被引：9，自引：2，他引：9  
李爽  姚静 《地理科学进展》2005,24(6):99-108
数字高程模型是支撑地理过程模型研究的重要基础数据。DEM数据获取、加工及压缩精度直接影响地学相关模型及地理过程的模拟效果和研究质量。在分析比较当今国际地学界应用DEM数据源的基础上，我们采用绝对差值法和三维剖面法对国家基础地理信息中心生产的基于1：50,000扫描地形图DEM产品(NFGIS_DEM)、GTOPO30_DEM数据及基于SRTM数据生产的DEM数据集进行了精度检验及评估。同时分析了影响由SRTM数据所生产的全球范围DEM数据集精度与数据质量。研究结果表明30-90m分辨率的SRTM_DEM产品在精度和数据质量控制方面远优于GTOPO30_DEM数据，与NFGIS_DEM数据质量相当。大范围乃至全球范围的30m分辨率SRTM_DEM产品，将极大促进基于DEM数据的地理过程模型的研究，尤其会大幅提升对DEM空间分辨率较敏感的地学相关研究能力。  相似文献   

15.
The article gives an overview of the work pursued by the medical geography research group in Trondheim. Activities are centred on a mortality data base containing more than 800,000 individual records for 1966–1985, with very flexible options for geographical manipulation. In addition, several other data bases are being used. References are made to research on regional variations and trends in cardiovascular disease and some cancers, and their potential causes, to comparisons between mortality patterns in Iceland and Norway, and to a thesis on aspects of the health and health care system in Poland.  相似文献   

16.
从《地理学报》创刊85年载文审视中国地理学发展特征   总被引：2，自引：0，他引：2  
何书金  刘昌明  袁振杰 《地理学报》2019,74(11):2209-2229
在《地理学报》创刊85周年之际,采用Citespace可视化为特征的科学文献计量方法,对1934-2018年《地理学报》4129篇载文的主题、引文和关键词等特征进行可视化分析,系统分析其1934-1949年创办时期、1950-1966年转型时期、1978-1995年成长时期以及1996年以后的创新发展时期4个不同时期出版的学术论文的主题脉络、知识演进、历史热点和机构发展。《地理学报》历年载文所体现的主题脉络持续变化、知识演进的不断前推、历史热点的交换更替以及载文机构的全面发展都充分体现出地理学在过去、现在与未来的自我革新力和蓬勃生命力。研究分析发现,自然地理学、人文地理学、遥感与地理信息系统和生态环境学在《地理学报》发展的不同时期都起到了重要引领作用。虽然4个主要领域的研究热度长盛不衰,但也大致经历了由自然地理向自然地理与人文地理并举,再向人地环境系统的交叉综合。其过程呈现出四大转变,即：① 研究视角的转变：迈向综合、交叉和融合的地理学研究;② 研究内容的转变：从自然要素和人文要素,到人地综合系统耦合的过程、机制和影响;③ 研究范式的转变：迈向理性科学主义和人文主义的融合;④ 研究方法和技术的转变：从田野观测和数字模拟到多源时空监测和耦合模拟。在此基础上,中国地理学者应进一步健全研究理论体系,改进研究范式,不断夯实地理科学的内核,并同时以更加开放的态度,吸收、引进相关学科的知识和方法,增强共识,走融合发展之路。  相似文献   

17.
Ontology is a significant research theme in GIScience. While some researchers believe that the progress in GIScience is being directed through an engagement with the concept of ontology, some dismiss it as irrelevant. This paper is aimed at (i) exploring the theoretical and practical roles of ontologies; (ii) making the definitions and terminology explicit; (iii) assessing the applicability of ontology to problems in the geographical domain; and (iv) assessing whether a unified approach to ontology exists in GIScience. The results will be helpful for GIScientists in (i) understanding the validity of employing ontology within their own work, (ii) assessing what operational framework of terms and methods to use for developing their own ontology, and (iii) to assess what existing ontological models are available and applicable within their domain or application. A comprehensive and critical review will also help in identifying the signficant issues and directing future research agenda in GIScience.  相似文献   

18.
论地理信息系统及其在地理学中的地位   总被引：44，自引：0，他引：44  
地理信息系统技术的兴起代表了地理学发展的一个重要方向。地理信息系统是一门处理地理(空间)数据的综合信息技术,它属于技术地理学的范畴,它为资源与环境的管理和规划以及地理学的研究提供了一个革命性工具。另一方面,地理信息系统的建立和应用又依赖于地理学理论和实用模型的发展。进一步勾通地理信息系统与空间分析之间的关系是目前促进地理信息系统发展的重要课题。  相似文献   

19.
Abstract

Databases used in geographical information systems must be supplied with current data. Maps are usually out of date when they are published. Satellite imagery and aerial photographs supply up-to-date three-dimensional data. Three different models for real-time quality assurance control in three-dimensional data collection for geographical information systems are discussed. Emphasis is placed on the visual detection of ‘blunders’ in three-dimensional data. One data collection quality assurance model has been implemented in the Photogrammetric Analysis Laboratory at Purdue University. An example from this system is given and the precision and speed of digitization of three-dimensional data are discussed.  相似文献   

20.
刘彦随  冯巍仑  李裕瑞 《地理学报》2020,75(10):2029-2046
农业地理学是农业科学与地理科学的交叉学科,农业地理工程是地理学与工程学交叉研究在现代农业与乡村领域的进一步深化和系统应用。随着现代农业科学技术和人地系统科学的创新发展,区域农业基础建设的科技需求日益旺盛,农业地理工程试验成为农业工程技术研发和农田系统管理的重要任务。本文阐述了农业地理工程的科学内涵、试验原理与技术方法,并以黄土丘陵沟壑区为例开展了地理工程试验研究和农业高质量发展对策探讨。结果表明：① 农业地理工程试验主要包括针对特定区域地理环境和农业发展问题的水土配置、土层复配、大田试验、生态防护、地理空间分析与监测,旨在探明区域高标准农田建设、健康农业生态系统营造的水土气生资源要素耦合规律,建立可持续土地利用系统与多功能农业经营模式。② 农业生态系统试验主要包括沟道边坡防护方式、健康农田系统结构、作物与土壤匹配关系、耕地投入产出经济分析,通过开展土地改良、作物优选交互试验和田间试种,揭示新造地“作土关系”耦合机理与优化调控途径。③ 作土关系优化调控是工程试验设计的主要内容,包括气候—作物优选、土体结构改良、地形—作物优选、土壤质量改良、土壤—作物优选、效益—作物优选6个阶段。④ 农业地理工程技术应用的核心任务是深化贯通综合研究、揭示微观耦合机理、建立工程试验范式,其应用路径主要体现在时间维、空间维与逻辑维三个维度。新时期农业地理工程试验与示范应用,有利于丰富农业地理学前沿理论与方法论,对于推进地理工程化研究和服务农业农村高质量发展决策具有重要意义。  相似文献   

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