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1.
Abstract

This paper describes a framework for the role of geographical information systems (GIS) in the monitoring and management of hazardous waste sites. Compilation of required information, incorporation of existing strategies for waste monitoring, analysis of these data in a GIS environment and the integration of computerized models for transport processes are discussed. Examples for the analysis of spatial data using techniques of cartographic overlay and the implementation of geo-statistical methods on monitoring data are provided from work in progress by the authors. These examples are set in the context of developing a fully integrated monitoring and management system utilizing GIS technology.  相似文献   

2.
Abstract

The field of geographical information systems (GIS) is reviewed from the viewpoint of spatial analysis which is the key component of the familiar four-part model of input, storage, analysis and output Input is constrained by the limits of manual methods and problems of ambiguity in scanning. The potential for developments in output is seen to be limited to the query mode of GIS operation, and to depend on abandoning the cartographic model. Discussion of storage methods is organized around the raster versus vector debate and the need to represent two spatial dimensions in one. A taxonomy of GIS spatial analysis operations is presented together with a generic data model. Prospects for implementation are discussed and seen to depend on appropriate scales of organization in national and international academic research.  相似文献   

3.
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   

4.
Abstract

This article is an agreed summary of a workshop held in Sheffield between 18-20 March 1991. The focus here is on three of the themes of the workshop: the mutual benefits of closer links between geographical information systems (GIS) and the methods of spatial data analysis (SDA); the specific areas of SDA that should be linked with GIS; how the linkage should be made in practice. Directions for future research are also reviewed. The emphasis throughout is on statistical SDA and principally from the perspective of human rather than physical geography.  相似文献   

5.
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   

6.
Abstract

Although biological diversity has emerged in the 1980s as a major scientific and political issue, efforts at scientific assessment have been hampered by the lack of cohesive sets of data. We describe, in concept, a comprehensive national diversity information system, using geographical information system (GIS) techniques to organize existing data and improve spatial aspects of the assessment. One potential GIS analysis, to identify gaps in the network of nature reserves for California, is discussed in greater detail. By employing an information systems approach, available data can be used more effectively and better management strategies can be formulated.  相似文献   

7.
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   

8.
Abstract

Growth in the available quantities of digital geographical data has led to major problems in maintaining and integrating data from multiple sources, required by users at differing levels of generalization. Existing GIS and associated database management systems provide few facilities specifically intended for handling spatial data at multiple scales and require time consuming manual intervention to control update and retain consistency between representations. In this paper the GEODYSSEY conceptual design for a multi-scale, multiple representation spatial database is presented and the results of experimental implementation of several aspects of the design are described. Object-oriented, deductive and procedural programming techniques have been applied in several contexts: automated update software, using probabilistic reasoning; deductive query processing using explicit stored semantic and spatial relations combined with geometric data; multiresolution spatial data access methods combining poini, line, area and surface geometry; and triangulation-based generalization software that detects and resolves topological inconsistency.  相似文献   

9.
Abstract

The wide variety of research into aspects of geographical information systems (GIS) undertaken at the Natural Environment Research Council's Unit for Thematic Information Systems is described. This includes work on spatial data models, on the application of artificial intelligence to improve the quality of input of remotely-sensed data, on automation of map cataloguing, on improving display and on GIS modelling.  相似文献   

10.
Abstract

Vector data storage has various advantages in a cartographic or geographical information system (GIS) environment, but lacks internal spatial relationships between individual features. Quadtree structures have been extensively used to store and access raster data. This paper shows how quadtree methods may be adapted for use in spatially indexing vector data. It demonstrates that a vector quadtree stored in floating point representation overcomes the classical problem with raster quadtrees of data approximation. Examples of vector quadtrees applied to realistic size data sets are given  相似文献   

11.
Abstract

Research on time and data models for Geographical Information Systems (GIS) has focused mainly in the representation of temporal geographical entities and implementation of temporal databases. Many temporal GIS database structures have been proposed but most of them just provide principles, not the recipe for the design. Owing to the manipulation of the large quantity of geographical information and the slow response time, few implementations exist. This paper presents a relational method of storing and retrieving spatial and temporal topologies. Two-level state topologies are proposed: a state topology for a set of geographical entities and a state topology for a single geographical entity.

From a temporal perspective, these two-level state topologies may also be viewed as two-level time topologies: a time topology for all geographical entities in a GIS database and a time topology for a single geographical entity. Based on these state and time topologies, a detailed storage approach for historical geographical information is provided.  相似文献   

12.
Abstract

Modelling of erosion and deposition in complex terrain within a geographical information system (GIS) requires a high resolution digital elevation model (DEM), reliable estimation of topographic parameters, and formulation of erosion models adequate for digital representation of spatially distributed parameters. Regularized spline with tension was integrated within a GIS for computation of DEMs and topographic parameters from digitized contours or other point elevation data. For construction of flow lines and computation of upslope contributing areas an algorithm based on vector-grid approach was developed. The spatial distribution of areas with topographic potential for erosion or deposition was then modelled using the approach based on the unit stream power and directional derivatives of surface representing the sediment transport capacity. The methods presented are illustrated on study areas in central Illinois and the Yakima Ridge, Washington.  相似文献   

13.
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14.
“面向区域”的GIS控件的设计与使用   总被引：4，自引：0，他引：4  
陈正江 《地理研究》2003,22(2):227-236
本文提出了一个“面向区域”GIS控件的概念———即以特定的地理区域为对象,将基础地理信息连同有关的GIS功能操作融合为一个可重用的程序模块,以Microsoft的COM(即“组件对象模型”)技术为基础,组织为“GIS化”的ActiveX控件。这种GIS控件,将面向对象技术中的“对象”扩展到了整个特定的地理区域空间,其核心思想是不仅封装了GIS的数据模型,必要的功能操作,而且封装了所有的基础地理信息。由于省去了对空间数据的处理,因而这种GIS控件可被广大非GIS专业的信息系统开发者灵活、简便地用于各种管理信息系统、办公自动化系统和决策支持系统的GIS功能扩充,也可用于构建一般的地理信息系统,因而有利于GIS技术应用的普及。文章最后给出了有关陕西省的应用实例  相似文献   

15.
Abstract

Remotely-sensed data constitute a major potential source of input to geographical information systems (GIS)However, these data often have a relatively poor classification accuracy compared with that of the cartographic data from maps with which they may be combined in the course of GIS analysis. The possibility exists of using data sets (in the form of digital maps) resident within a GIS in order to improve this accuracy, before the classified image is incorporated into the GIS. Results are discussed from a British Alvey Information Technology project to develop a system for the knowledge-based segmentation and classification of remotely-sensed terrain images, in which the knowledge contained in digital map  相似文献   

16.
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17.
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18.
Abstract

This is the first of two papers elaborating a framework for embedding urban models within GIS. This framework is based upon using the display capabilities of GIS as the user interface to the conventional modelling process, beginning with data selection and analysis, moving to model specification and calibration, and thence to prediction. In this paper, we outline how various stages in this process based on purpose-built software outside the system, are accessed and operated through the GIS. We first deal with display based on thematic maps, surfaces, graphs and linked windows, standard to any data from whatever source, be it observations, model estimates or predictions. We then describe how various datasets are selected, how the spatial system can be partitioned or aggregated, and how rudimentary exploratory spatial data analysis enables scatterplots to be associated with thematic maps. We illustrate all these functions and operations using the proprietary GIS ARC-INFO applied to population data at the tract level in the Buffalo region. In the second part of the paper, various residential location models are outlined and the full modelling framework is assembled and demonstrated.  相似文献   

19.
Editorial     
Abstract

The analysis of geographical information is compared with other production processes in which a user can only accept an end-product if it meets certain quality requirements. Whereas users are responsible for defining the levels of quality they need to use the results of the analyses of geographical information systems in their work, database managers, experts and modellers could greatly assist users to achieve the quality of results they seek by formalizing information on: (1) data collection, level of resolution and quality; (2) the use of the basic analytical functions of the geographical information system; and (3) the data requirements, sensitivity and error propagation in models. These meta-data could be incorporated in a knowledge base alongside the geographical information system where, together with procedures for on-line error propagation, a user could be advised on the best way to achieve a desired aim. If the analysis showed that the original constellation of data, methods and models could not achieve the aim with the desired quality, the intelligent geographical information system would present a range of alternative strategies—better methods, more data, different data, better models, better model calibration, or better spatial resolution—and their costs by which the user's aims could reasonably be achieved.  相似文献   

20.
Abstract

This paper reports on software to construct alternative weight matrices and to compute spatial autocorrelation statistics, namely the Moran coefficient and the Geary coefficient using Arc/Info’s data structure. As such it is an addition to recent efforts in linking GIS with exploratory spatial data analysis. The software is interfaced with Arc/Info via the Arc Macro Language (AML) so that it can be run in the ARC environment. This allows the user to perform exploratory analysis within GIS which may provide insights in subsequent spatial analysis and modelling.  相似文献   

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