Remotely-sensed data as an information source for geographical information systems in natural resource management a review

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.     

Resource utilization and regional planning information systems (RURPIS) in Botswana

Abstract

Problems with data organization for increasingly complex resource utilization and regional programmes have encouraged Botswana to turn to a geographical information systems approach. A major project to carry this out, based in the Department of Environmental Science, University of Botswana, is outlined in this paper. The paper documents the design of the programme and lists its modules and variables. It also reports on important considerations that have been taken into account in evaluating the programme's data sets and gives results from an illustrative pilot project that has been undertaken.     

Mapping glacier velocities on Svalbard using ERS tandem DInSAR data

The results presented show how glacier velocities can be measured and calculated from Earth Resources Satellite (ERS) tandem interferometric synthetic aperture radar (InSAR) data by the use of geographical information systems (GIS) and non-interferometric software. A semi-automatic algorithm using existing and newly implemented modules in ESRI's GIS software Arc has been developed to unwrap existing height differentiated interferometric SAR (DInSAR) data. The algorithm is applied to a data set covering glaciers from the arctic archipelago Svalbard. Estimated DInSAR velocities are decomposed into the glacier surface flow direction using a digital elevation model (DEM). Velocity fields for the glaciers Isachsenfonna, Akademikerbreen and Nordbreen on Svalbard are presented.     

Environmental decision support system project: an exploration of alternative architectures for geographical information systems

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.     

A review of temporal database research and its use in GIS applications

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.     

The use of digital map data in the segmentation and classification of remotely-sensed images

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     

An information systems approach to the preservation of biological diversity

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.     

Performance evaluation and work-load estimation for geographic information systems

Abstract

Agencies acquiring GIS hardware and software are faced with uncertainty at two levels: over the degree to which the proposed system will perform the functions required, and over the degree to which it is capable of doing so within proposed production schedules. As the field matures the second concern is becoming more significant. A formal model of the process of acquiring a GIS is presented, based on the conceptual level of defining GIS sub-tasks. The appropriateness of the approach is illustrated using performance data from the Canada Land Data System. It is possible to construct reasonably accurate models of system resource utilization using simple predictors and least squares techniques, and a combination of inductive and deductive reasoning. The model has been implemented in an interactive package for MS-DOS systems.     

A spatial analytical perspective on geographical information systems

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.     

Interactive GIS for environmental risk assessment

Abstract

Geographical Information Systems can be used for processing spatial data to assess the risks of environmental contamination. Their use depends upon the amount and quality of available data, the models for interpolation and calculation of health risk, data processing procedures and interactivity. In this study, it is shown that interactive use of GIS is important for obtaining physically relevant results. Three forms of interactivity are distinguished: interactivity by means of user interfacing, interactivity requiring additional information outside GIS and interactivity when changing the use of GIS. Three stages in which interaction with GIS are crucial can be distinguished: application of geostatistics, choice of appropriate models, and decision making. This study focuses on three cases in The Netherlands dealing with soil contamination and soil stress analysis and with implications for risk assessment in which interactivity within GIS is analysed. Emphasis is given to contour volumes of polluted soil, to combine GIS with deterministic models and to apply land use scenarios. Finally, there is a discussion of how some forms of interactivity could be replaced by expert systems.     

Requirements and principles for the implementation and construction of large-scale geographic information systems

Abstract

This paper provides a brief survey of the history, structure and functions of ‘traditional’ geographic information systems (GIS), and then suggests a set of requirements that large-scale GIS should satisfy, together with a set of principles for their satisfaction. These principles, which include the systematic application of techniques from several sub-fields of computer science to the design and implementation of GIS and the integration of techniques from computer vision and image processing into standard GIS technology, are discussed in some detail. In particular, the paper provides a detailed discussion of questions relating to appropriate data models, data structures and computational procedures for the efficient storage, retrieval and analysis of spatially-indexed data.     

Data integration through region-based nominal filtering

Abstract

Resource models integrating disparate nominal or class grid-cell data can be implemented by using spatial filters. Most modelling procedures do not adequately handle noise created during the process of merging and integrating multiple grid-cell data sets. Data integration can be best accomplished in an environment where ready access to statistical and database management systems support the reclassification of noise grid-cells. These systems provide access to functionality and information which support the design of the spatial filter and the evaluation of the result of the spatial filter and the resource model.     

The economic evaluation of implementing a GIS

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.     

Teach yourself geographical information systems The design,creation and use of demonstrators and tutors

Abstract

Abstract In the United Kingdom, as in many other countries, interest is growing rapidly in the nature and capabilities of geographical information systems (GIS). Given the relatively small number of systems currently in use and, in particular, the very restricted number of individuals who have used GIS for a wide range of applications, a conflict of interests arises. It is desirable that education and training are provided on demand and that ad hoc queries are answered: yet the provision for this advice and teaching falls at present upon the most skilled and expert proponents and diminishes their capability to develop or exploit GIS in other ways. The increase in demand for training can, in principle, be satisfied by the creation and use of a computerized tutor which deals with the fundamental concepts of GIS. ARCDEMO is a demonstrator, a primitive tutor, developed to show the capabilities of the ARC/INFO GIS, and its design and implementation arc described. The system contains both text and multicolour graphics, sections of which can be viewed in sequence or selectively from a menu. Operations covered by the demonstrator include: automatic validation and correction of data; change of projection; selective retrieval of spatial data; map overlay; and network analysis. A second demonstrator, called ECDEMO, was developed from the basic structure of ARCDEMO but illustrates an environmental data base established for the European Community. We describe the extent of use and successes and failures of these demonstrators and, on the basis of this experience, we set out desiderata for fully-fledged tutors, suggest the contributions which could be made by knowledge-based systems, outline the machine and human resources needed for running such tutors and conjecture the merits of an international collaborative project to set up a GIS tutor with appropriate national data sets.     

Fuzzy information representation and processing in conventional GIS software: database design and application

Currently used methods for representing geographical information are inadequate because they do not tolerate imprecision. This leads to information loss and inaccuracy in analysis. Such expressive inadequacy is largely due to the underlying membership concept of classical set theory. To improve information processing in GIS research and application, an alternative membership concept is required. In this paper, we explore the inadequacy imposed upon geographical information representation by classical set theory and address the problems of information loss. A fuzzy relational data model is defined which is more representative for geographical information. A GIS database for agricultural land resource management is created by using the data model and a new technique for assessing land suitability is developed. The fuzzy representation largely facilitates data analysis in this GIS. The methods are tested with data from North Java, Indonesia using a vector-based GIS software package, Arc Info, and the analysis results are presented.     

Forthcoming events

Abstract

This is the second of two papers which elaborates a framework for embedding urban models within GIS. In the first paper (Batty and Xie 1994), we outlined how the display functions of a proprietary GIS could be used to organize a series of external software modules which contained the central elements of the modelling process, namely dataset selection and analysis, and model specification, calibration, and prediction. In that paper, we dwelt on display and data analysis functions whereas here we outline the model-based functions of the system. We begin by reviewing residential location models based on population density theory, stating continuous and discrete model forms, and calibration methods. We then illustrate a pass through the software using data for the Buffalo urban region, showing how observed data and model estimates can be evaluated through graphic display. We present ways in which the system can be used to explore and fit a variety of models to different zoning systems and in so doing, show how subset selection and aggregation can be used to find models with good fit. Finally we draw conclusions and outline an agenda for further research.     

The research agenda of the European Science Foundation's GISDATA scientific programme

Abstract

In January 1993 the European Science Foundation launched a four-year scientific programme on geographical information systems. The programme aims at overcoming the existing fragmentation of GIS research in Europe and addresses three key areas: European-wide data base design, data integration, and social and environmental applications. In each of these areas a number of priorities have been identified which provide the focus of the initiatives and collaborative ventures envisaged by the programme. This article describes the programme's research agenda and sets it in the context of the activities of the European Science Foundation.     

Research related to geographical information systems at the Natural Environment Research Council's Unit for Thematic Information Systems

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.