An Approach to leaching Applied GIS: Implementation for Local Organizations

Abstract

Geographic information systems (GIS) is a fairly new and evolving curriculum area within geography and other disciplines at colleges and universities in the United States. The challenge of teaching underlying concepts of GIS functionality, the details of computer operation and software interfaces, as well as the contexts of various applications can be a difficult one. At Indiana University of Pennsylvania, a teaching strategy—Client-Life Cycle GIS Project Learning—has been introduced in which students in an upper level GIS course work with local organizations, faculty from other university departments, and governmental entities. This allows students with some GIS background to work with real clients; utilize and operationalize the concepts of the GIS Project Life Cycle; make the connection between data development, analysis, and applications development; provide expertise and needed data to local organizations; and see the utility and impact of their work. A group pilot project from the spring semester of 1998 is discussed to illustrate how students responded to this method of teaching GIS.     

The role for a geographical information system in a large environmental project

Abstract

A geographical information system (GIS) has proved to be a valuable tool in the Direct/Delayed Response Project—a comprehensive examination of the future, long-term chemical response of surface waters to acidic deposition. The role of the GIS within the project includes aggregation, analysis and display of various forms, scales and projections of environmental data related to acidic deposition. The GIS is particularly valuable for effectively communicating key scientific findings and results of regional, national and international importance to a diverse audience.     

Topographic solar radiation models for GIS

Abstract

Incident solar radiation at the Earth's surface is the result of a complex interaction of energy between the atmosphere and the surface. Recently much progress has been made towards the creation of accurate, physically-based solar radiation formulations that can model this interaction over topographic and other surfaces (such as plant canopies) for a large range of spatial and temporal scales. In this paper we summarize our current work on solar radiation models and their implementation within both GIS and image processing systems. An overview of the effects of topography and plant canopies on solar radiation is presented along with a discussion of various options for obtaining the data necessary to drive specific solar radiation models. Examples are given from our own work using two models, ATM (Atmospheric and Topographic Model), a model based within an image processing framework, and SOLARFLUX, a GIS-based model. We consider issues of design, including GIS implementation and interface, computational problems, and error propagation.     

Research Article. Modelling inside GIS: Part 1. Model structures,exploratory spatial data analysis and aggregation

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.     

Aspects of the implementation of the GEOVIEW design

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.     

Finite-element mesh generation from mappable features

Abstract

A vector-based geographical information system (GIS) is used to generate a variably-sized triangular element finite-element mesh from mappable features. Important digitally-mapped features are automatically linked to nodes in the finite-element model, ensuring an efficient, virtually error-free alternative to the tedious process of mesh design and data-input preparation by other methods. The procedure permits the user to work interactively with graphically-displayed hydrologic information about the study area allowing different mesh sizes to be used as needed, based on hydrologic complexity. The mesh-generaiion programs are stand-alone macros within the GIS that set up the basic data defining a finite-element mesh for many different finite-element model programs.     

Designing a personal guidance system to aid navigation without sight: progress on the GIS component

Abstract

This paper reports on progress towards the development of a personal guidance system for a blind navigator. The system is being developed in light of the unique problems facing the blind traveller, which are discussed first. The system consists of four modules: a locator unit, a detailed spatial database, an algorithm for path selection and a user interface. Suggestions are offered for alternative ways of handling the locator problem using a global positioning system or a database query system. The nature of the geographic information system (GIS) to be used as a host for the database is discussed, followed by brief statement of the criteria for choosing an algorithm for path selection and suggestions on types of user interfaces best suited to the system. A report on a pilot-study GIS is presented. Special problems of database and system design are highlighted.     

HyperArc: a task-oriented hypertext GIS interface

Abstract

The rationale, development and -implementation of a task-oriented hypertext GIS interface (HyperArc) are described. HyperArc is a fully functional interface on an Apple Macintosh computer acting as a client to a host computer running the ARC/INFO GIS. The package has been developed using the HyperCard package, and makes full use of the Apple Macintosh WIMP interface, enabling the user to perform a range of standard ARC/INFO tasks, including a variety of map displays and data queries. The key advantage of this kind of interface is that it permits the creation of tasks or sets of spatial procedures which can be easily customised and executed by the end user without any knowledge of the system command language.     

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.     

Observational Work for Children

Abstract

Geographic information systems (GIS) are computer-based tools for geographic data analysis and spatial visualization. They have become one of the information and communications technologies for education at all levels. This article reviews the current status of GIS in schools, analyzes the requirements of a GIS-based learning environment from constructivist perspectives, and discusses the major issues in the design of a constructivist GIS-based learning environment based on experience from the development of World Explorer, a GIS-based learning environment that provides a theme-oriented data and information base, supports multiple representations and multiple linkages of information, and facilitates interactive learning and knowledge construction.     

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.     

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.     

Spatial video and GIS

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.     

An inductive modelling procedure based on Bayes' theorem for analysis of pattern in spatial data

Abstract

This paper describes an inductive modelling procedure integrated with a geographical information system for analysis of pattern within spatial data. The aim of the modelling procedure is to predict the distribution within one data set by combining a number of other data sets. Data set combination is carried out using Bayes’ theorem. Inputs to the theorem, in the form of conditional probabilities, are derived from an inductive learning process in which attributes of the data set to be modelled are compared with attributes of a variety of predictor data sets. This process is carried out on random subsets of the data to generate error bounds on inputs for analysis of error propagation associated with the use of Bayes’ theorem to combine data sets in the GIS. The statistical significance of model inputs is calculated as part of the inductive learning process. Use of the modelling procedure is illustrated through the analysis of the winter habitat relationships of red deer in Grampian Region, north-east Scotland. The distribution of red deer in Deer Management Group areas in Gordon and in Kincardine and Deeside Districts is used to develop a model which predicts the distribution throughout Grampian Region; this is tested against red deer distribution in Moray District. Habitat data sets used for constructing the model are accumulated frost and altitude, obtained from maps, and land cover, derived from satellite imagery. Errors resulting from the use of Bayes’ theorem to combine data sets within the GIS and introduced in generalizing output from 50 m pixel to 1 km grid squares resolution are analysed and presented in a series of maps. This analysis of error trains is an integral part of the implemented analytical procedure and provides support to the interpretation of the results of modelling. Potential applications of the modelling procedure are discussed.     

An event-based spatiotemporal data model (ESTDM) for temporal analysis of geographical data

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.     

Guidelines for demonstrating geographical information systems based on participatory development

Abstract

The transfer of GIS technology has not met with uniform success in lesser-developed countries. It has been argued that this may be due to many efforts being technology-driven rather than demand-driven. In agricultural development, technology is transferred through a demand-driven participatory approach which incorporates the ultimate recipients of the technology in the design, implementation and evaluation of projects. A project to demonstrate the use of GIS technology for wasteland development in India involving seven Indian research institutes was undertaken by the U.S. Agency for International Development. In the Indian GIS demonstration, technical approaches proposed by each institute were largely technology-driven. To counter this tendency, a set of evaluation criteria or guidelines based on the participatory approach was developed to refine proposals.     

Efficiently implementable algebra for distributed in-network spatial analysis

Existing sensor network query processors (SNQPs) have demonstrated that in-network processing is an effective and efficient means of interacting with wireless sensor networks (WSNs) for data collection tasks. Inspired by these findings, this article investigates the question as to whether spatial analysis over WSNs can be built upon established distributed query processing techniques, but, here, emphasis is on the spatial aspects of sensed data, which are not adequately addressed in the existing SNQPs. By spatial analysis, we mean the ability to detect topological relationships between spatially referenced entities (e.g. whether mist intersects a vineyard or is disjoint from it) and to derive representations grounded on such relationships (e.g. the geometrical extent of that part of a vineyard that is covered by mist). To support the efficient representation, querying and manipulation of spatial data, we use an algebraic approach. We revisit a previously proposed centralized spatial algebra comprising a set of spatial data types and a comprehensive collection of operations. We have redefined and re-conceptualized the algebra for distributed evaluation and shown that it can be efficiently implemented for in-network execution. This article provides rigorous, formal definitions of the spatial data types, points, lines and regions, together with spatial-valued and topological operations over them. The article shows how the algebra can be used to characterize complex and expressive topological relationships between spatial entities and spatial phenomena that, due to their dynamic, evolving nature, cannot be represented a priori.     

Computing aspects of a large geographic information system for the European Community

Abstract

The CORINE programme (Co-ordinaled' Information on the European Environment) has been underway since 1985. Its purpose is to provide information on the environment of the entire European Community in a form suitable for assisting policy making. Such data must be accurate, integrated and readily available to the personnel for whom the system is designed. The system must be capable of dealing with large amounts of spatially-linked data from many different sources, in text, vector or raster form. The use of a geographic information system (GIS) is therefore essential. This paper describes the use of an interim system as a ‘bed’ for beginning the process of acquiring and integrating data. The data sets available are soils, climate, topography and ‘biotopes) (important areas for nature conservation). A data transfer format has been devised to provide for ease of transfer between various sites in the European Community with different mainframe computers. The interim system ensures that the needs of users can be defined and provides valuable user experience before a permanent system is installed. Other issues examined include the use of national and international networks and problems of integrating data when incorporating existing digital data from disparate sources into a large GIS.     

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     

A GIS-based approach to multiple criteria group decision-making

Abstract

The multiple criteria group decision-making problem involves a set of feasible alternatives that are evaluated on the basis of multiple, conflicting and noncommensurate criteria by a group of individuals. This paper is concerned with developing a GIS-based approach to group decision-making under multiple criteria. The approach integrates, within a raster GIS environment, the Technique for Order Preference by Similarity to Ideal Solution (TOPSIS) and Borda's choice rule. TOPSIS orders the feasible alternatives according to their closeness to the ideal solution. It is used to derive the individual preference orderings. Borda's method combines the individual preferences into a group preference or consensus/compromise ranking. The approach is implemented within the IDRISI GIS and illustrated on a hypothetical decision situation.