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1.
Abstract

A great deal of recent work in computer science applies itself to temporal database design. Designers of geographical information systems (GIS) can build on this work to create a temporal GIS capability to trace geographical change and understand geographical processes. This paper reviews temporal research in information processing, contrasts various proposed temporal database designs and summarizes the problems of adapting it to GIS requirements.  相似文献   

2.
Abstract

GEOVIEW, an integrated system, uses relational database technology and a graphics package (Graphical Kernel System) to offer a flexible environment in which to develop applications of geographical information systems (GIS). It has facilities to represent data in different spatial data structures. Data are stored and retrieved efficiently by using variable length raw data. The unified representation offers the benefit of storing entities in a single relation and eases the process of overlaying different entities. GEOVIEW also provides a mechanism for tailoring user interfaces to suit the needs of different applications by means of a facility to generate macros and menus.

Processing requirements for GIS applications can be supported by using tools provided by relational database technology and by graphics packages. High-level language interfaces which can process dynamic statements and bind dynamic variables are needed to develop an efficient database interface module. A graphics segment facility is essential to provide editing functions and to maximize the use of the local processing power of graphics workstations in the graphics interface module. Further improvements in performance can be made by using the array fetch facility and linear keys for spatial searching.  相似文献   

3.
Why not SQL!     
Abstract

The application of traditional database query languages, primarily the Structured Query Language SQL, for geographical information systems (GIS) and other non–standard database applications has been tried unsuccessfully; therefore, several extensions to the relational database query language SQL have been proposed to serve as a spatial query language. It is argued that the SQL framework is inappropriate for an interactive query language for a GIS and an extended SQL is at best a short term solution. Any spatial SQL dialect has a number of serious deficiencies, particularly the patches to incorporate the necessary spatial concepts into SQL.  相似文献   

4.
Abstract

Representations historically used within GIS assume a world that exists only in the present. Information contained within a spatial database may be added-to or modified over time, but a sense of change or dynamics through time is not maintained. This limitation of current GIS capabilities has recently received substantial attention, given the increasingly urgent need to better understand geographical processes and the cause-and-effect interrelationships between human activities and the environment. Models proposed so-far for the representation of spatiotemporal data are extensions of traditional raster and vector representations that can be seen as location- or feature-based, respectively, and are therefore best organized for performing either location-based or feature-based queries. Neither form is as well-suited for analysing overall temporal relationships of events and patterns of events throughout a geographical area as a temporally-based representation.

In the current paper, a new spatio-temporal data model is proposed that is based on time as its organizational basis, and is thereby intended to facilitate analysis of temporal relationships and patterns of change through time. This model is named the Event-based Spatio Temporal Data Model (ESTDM). It is shown that temporally-based queries relating to locations can be implemented in an efficient and conceptually straightforward manner using ESTDM by describing algorithms for three fundamental temporally-based retrieval tasks based on this model: (1) retrieving location(s) that changed to a given value at a given time, (2) retrieving location(s) that changed to a given value over a given temporal interval, and (3) calculation of the total area that has changed to a given value over a given temporal interval. An empirical comparison of the space efficiency of ESTDM and compressed and uncompressed forms of the ‘snapshot’ model is also given, showing that ESTDM is also a compact representation of spatio-temporal information.  相似文献   

5.
A Pedagogic Framework to Link GIS to the Intellectual Core of Geography   总被引：4，自引：3，他引：1  
《The Journal of geography》2012,111(6):578-591
Abstract

This paper aims to develop a new pedagogic framework for teaching GIS at the college and university level using Berry's geographic matrix. By synthesizing different schools of thought, this paper argues that GIS education essentially involves two aspects—how to teach about GIS and how to teach with GIS. Berry's geographic matrix can be used to tie these dual aspects of GIS education together neatly. As an abstract representation of geographical phenomena, the geographic matrix embeds all three entities of GIS—location, attribute, time—and thus can help GIS instructors teach about GIS. As a synthesis of geographical approaches, the geographic matrix can assist GIS instructors teach with GIS. This paper demonstrates that GIS is actually an implementation of Berry's geographic matrix. Furthermore, the 10 approaches to geographical analysis, originally proposed by Berry for the geographic matrix, can be executed routinely in a GIS environment. By incorporating Berry's geographic matrix into GIS education, teachers can enable students to surpass technical issues and to appreciate the conceptual and functional linkages between GIS and geography's intellectual core.  相似文献   

6.
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7.
Abstract

A neglected aspect of facility location problems is the geometric representation of the facilities sited and clients served. Point objects represent these entities in most facility location problems. This can cause solution error and limit the range of potential solutions. The increasing capabilities of geographical information systems (GIS) to represent, store and manipulate spatial entities provides a substantial but unrealized potential for more sophisticated geometric representation in facility location problems. This paper provides a framework for realizing this potential. Specifically, this paper: (i) synthesizes existing formulations; (ii) develops a unified mathematical framework; (iii) identifies feasible computational strategies that can be implemented within a GIS framework, and; (iv) discusses potential GIS-based solution algorithms.  相似文献   

8.
Abstract

Recent changes in information technology offer the opportunity to explore alternative architectures for geographical information systems (GIS) which might better support advanced applications. This paper describes the architecture and implementation of the environmental decision support system (EDSS), a prototype GIS tool kit. The architecture is based on a simple yet powerful systems model using only data collections, views and operations as the basic entity types. The design of the user interface, data management and data analysis within the model are outlined, with particular emphasis on the advanced facilities for which implementation is simplified by the architecture. A prototype applications system, BANKSIA, is also described.  相似文献   

9.
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10.
Abstract

Many spatial decision-making problems, such as site selection or land use allocation require the decision-maker to consider the impacts of choice-alternatives along multiple dimensions in order to choose the best alternative. The decision-making process, involving policy priorities, trade-offs, and uncertainties, can be aided by Multiple Criteria Decision making (MCDM) methods. This paper presents a framework for integrating geographical information systems (GIS) and MCDM methods. In this framework the MCDM methods are classified and matched with choice heuristics used by the decision-makers in the presence of competing alternatives and multiple evaluation criteria. Two strategies for integrating GIS with MCDM are proposed. The first strategy suggests linking GIS and MCDM techniques using a file exchange mechanism. The second strategy suggests integrating GIS and MCDM functions using a common database. The paper presents the implementation of the first strategy using PC-ARC/INFO, a file exchange module, and four different MCDM computer programs.  相似文献   

11.
Abstract

Progress in technical database management systems offers alternative strategies for the design and implementation of databases for geographical information systems. Desirable extensions in the user data types and database management are reviewed. A prototype geographical database tool-kit, SIRO-DBMS, which provides some spatial data types and spatial access methods as external attachments to a kernel relational database management system, is described. An ability to fragment a large set of entities into several relations while retaining the ability to search the full set as a logical unit is provided. Implementation of the geometric data types is based on mapping the types of data into a set of attributes of the atomic types supported by the kernel and specifying the relational designs for the set of atomic attributes.  相似文献   

12.
Abstract

The National Science Foundation will soon establish a National Center devoted to geographical research and education based on geographical information systems (GIS). The Center will be located at a university chosen on the basis of competitive proposals that will be evaluated primarily on the quality of their research agendas. The winning institution will be expected to involve government agencies and private firms in Center operations and programmes, and it will be expected to serve the national GIS community. The Center arose from a suggestion made by a member of the GIS research community. A large-scale database initiative and a Foundation commitment to Science and Technology Centers provided an institutional environment hospitable to the Center. There are similarities and differences in the approach taken toward GIS research, policy and applications in the United Kingdom (UK) and in the United States (US). Those similarities and differences offer promising topics for collaborative research on GIS itself and on GIS as an information technology affecting the discipline of geography. Cross-national UK-US research would be a productive step toward the globalization of GIS and GIS research.  相似文献   

13.
Abstract

Implementation of geographical information systems (GIS) involves a substantial commitment of resources by the sponsoring agency. Economic evaluation of the proposed GIS is an important step in the implementation process. This article discusses the traditional benefit cost analysis and suggests alternative approaches which may prove useful in situations where the benefit cost model may not be appropriate. A case study of an actual implementation of a GIS which illustrates the approaches discussed is also presented.  相似文献   

14.
This article addresses the issue of linking temporal and spatial information into a GIS database structure to investigate the land-use changes in a rural-urban region over a thirty-five-year period. More specifically, it describes the application of a programming package developed to build temporal topology in an historical land-use GIS database to efficiently perform spatiotemporal queries. The program was created within the MapInfo environment using MapBasic language. Different types of information, such as the rate of change, the relationship between the change of land use and zoning regulations, and land-use succession were extracted from the database. A user-friendly interface was also developed to easily address spatiotemporal queries to the database. This approach represents a flexible and performing tool for scientists and planners who need to efficiently capture essential spatiotemporal information required for geographical inquiry and decision-making.  相似文献   

15.
Abstract

A raster/quadtree geographical information system (GIS) was established For a 932 ha natural area in central Missouri. The GIS contained map layers depicting vegetative cover from 1939 to 1982, soils, topographic aspect and distance from a forest seed source. Discriminant function analysis was used to quantify and describe ecological succession on the area during this period. The calibration of discriminant functions is discussed, as are the statistical and spatial validations of the model. It was concluded that this approach provides a useful technique to examine long-term temporal phenomena in a spatial context.  相似文献   

16.
Abstract

In state-of-the-art GIS, geographical features are represented as geometric objects with associated topological relations and classification attributes. Semantic relations and intrinsic interrelations of the features themselves are generally neglected. In this paper, a feature-based model that enhances the representation of geographical features is described. Features, as the fundamental depiction of geographical phenomena, encompass both real world entities and digital representation. A feature-based object incorporates both topological relations among geometric elements and non-topological (semantic) relations among features. The development of an object-oriented prototype feature-based GIS that supports relations between feature attributes and feature classes is described. Object-oriented concepts such as class inheritance and polymorphism facilitate the development of feature-based GTS.  相似文献   

17.
Abstract

The space-time Of time geographical framework is a powerful perspective from which to analyse human behaviour. One of the central concepts in this framework is the space-time prism, which models individual accessibility to an environment. In this paper, the derivation and manipulation of space-time prism concepts within a geographical information system (GIS) are discussed. The required system inputs and desired outputs are identified and a generic GIS based procedure is presented Given these basic requirements, issues are discussed which can determine the feasibility of current GIS technology to handle the derivation of space-time prism concepts.  相似文献   

18.
This article addresses the issue of linking temporal and spatial information into a GIS database structure to investigate the land‐use changes in a rural‐urban region over a thirty‐five‐year period. More specifically, it describes the application of a programming package developed to build temporal topology in an historical land‐use GIS database to efficiently perform spatiotemporal queries. The program was created within the MapInfo environment using MapBasic language. Different types of information, such as the rate of change, the relationship between the change of land use and zoning regulations, and land‐use succession were extracted from the database. A user‐friendly interface was also developed to easily address spatiotemporal queries to the database. This approach represents a flexible and performing tool for scientists and planners who need to efficiently capture essential spatiotemporal information required for geographical inquiry and decision‐making.  相似文献   

19.
Abstract

A geographical information system (GIS) based study was carried out in a densely-populated watershed in Nepal. An evaluation of land use change between 1972 and 1990 indicated that there has been an increase in forest and agricultural land area and a decrease in shrubland and grassland area. GIS techniques were used to produce single and composite fertility index maps, which can be used for problem identification and planning. These maps indicate that forest soil fertility is generally poor in the watershed. GIS was found to be very beneficial in addressing critical resource issues in small watersheds in developing countries.  相似文献   

20.
《The Journal of geography》2012,111(6):285-295
Abstract

The purpose of this article is to describe a capstone course in undergraduate student geographical research in which GIS and other geospatial tools were used to teach undergraduate students basic geographical principles. The course uses the “cooperative learning” pedagogical approach to address one of a number of client-supplied research projects, chosen on the basis of logistical difficulty, time, student ability, and project importance. In the connection of primary data with existing data, students confronted a number of important research issues such as mapping ethics, database design and management, time management, group dynamics, and research limitations.  相似文献   

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