Showing papers in "International Journal of Geographic Information Systems in 1990"
TL;DR: Kriging is the method of interpolation deriving from regionalized variable theory that depends on expressing spatial variation of the property in terms of the variogram, and it minimizes the prediction errors which are themselves estimated.
Abstract: Geographical information systems could be improved by adding procedures for geostatistical spatial analysis to existing facilities Most traditional methods of interpolation are based on mathematical as distinct from stochastic models of spatial variation Spatially distributed data behave more like random variables, however, and regionalized variable theory provides a set of stochastic methods for analysing them Kriging is the method of interpolation deriving from regionalized variable theory It depends on expressing spatial variation of the property in terms of the variogram, and it minimizes the prediction errors which are themselves estimated We describe the procedures and the way we link them using standard operating systems We illustrate them using examples from case studies, one involving the mapping and control of soil salinity in the Jordan Valley of Israel, the other in semi-arid Botswana where the herbaceous cover was estimated and mapped from aerial photographic survey
1,632 citations
TL;DR: The underlying types of sensitivities for suitability analysis are delineated and ways to measure these sensitivities are derived and how to undertake geographical sensitivity analyses given a generic geographical information system is shown.
Abstract: The theory and methods for attribute error and sensitivity analysis associated with map-based suitability analysis are developed. In particular, this paper delineates the underlying types of sensitivities for suitability analysis and derives ways to measure these sensitivities. Additionally, it shows how to undertake geographical sensitivity analyses given a generic geographical information system. The uses of these methods include understanding the relationship of the attribute errors in the output map generated by errors in the input maps for a given geographical analysis. This information provides a means to assess the quality and reliability of conclusions inferred from the output map created by such an analysis.
312 citations
TL;DR: The applicability of an object-oriented design methodology to the design of geographical information systems is demonstrated and standard cartographic primitives are represented using IFO, which are used in the modelling of some standard administrative units in the United Kingdom.
Abstract: 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 r...
184 citations
TL;DR: The inadequacy imposed upon geographical information representation by classical set theory is explored and a fuzzy relational data model is defined which is more representative for geographical information.
Abstract: 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 analysi...
150 citations
TL;DR: In this paper, the authors used a modified measure of Euclidean distance to interpolate mid-slope positions from the stream and ridge lines by using a modified version of the standard geometrical distance metric.
Abstract: Terrain position (e.g., ridge, mid-slope, valley) is a potentially useful variable with which to model environmental parameters and processes using geographical information systems. Digital elevation data spaced on a regular 30 m grid were generated over an area of flat to moderate topography in south-east Australia. Streams and ridges were mapped from the digital elevation model using a new algorithm that utilizes basic geographical principles. Ridge and stream lines closely followed the original contour map and improved upon the results from three alternative algorithms. Mid-slope positions were successfully interpolated from the stream and ridge lines by a modified measure of Euclidean distance.
141 citations
TL;DR: A comprehensive national diversity information system is described, in concept, using geographical information system (GIS) techniques to organize existing data and improve spatial aspects of the assessment.
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.
132 citations
TL;DR: This work has reviewed available data models and concluded that the hybrid extended network model is appropriate for use in an SDSS context and designed a logical database structure for a locational analysis S DSS.
Abstract: The selection of a data model is an important step in designing a spatial decision support system (SDSS) because the database is the foundation of the system, and other system components must draw upon the database to perform analysis and display functions. The diversity of representations that must be maintained to support these functions often results in a complex database. One way to simplify the implementation of a complex database is to exploit features of a data model embedded in database management software. A methodology for SDSS conceptual database design was developed using the Entity-Category-Relationship approach. To accommodate this conceptual structure in database management software, we reviewed available data models and concluded that the hybrid extended network model is appropriate for use in an SDSS context. To illustrate this methodology, we designed a logical database structure for a locational analysis SDSS.
114 citations
TL;DR: The relative merits of five orderings (row, row prime, Hilbert, Morton and Gray code) are assessed empirically for four paradigmatic geographical data-processing tasks in spatial analysis and data management as discussed by the authors.
Abstract: Many spatial analysis algorithms for cellular representations and data structures are based on an ordering of cells or objects to transform a two-dimensional problem to a one-dimensional one. Several orderings are available and their differing properties influence the performance of the data structures and algorithms. The relative merits of five orderings (row, row prime, Hilbert, Morton and Gray code) are assessed empirically for four paradigmatic geographical data-processing tasks in spatial analysis and data management. It is concluded that the Hilbert ordering deserves further investigation.
109 citations
TL;DR: In this article, the authors present a system for exploring exploratory statistical analysis of spatial data using statistical graphics as further views of the data, which can be made active and thus provide alternative means of querying the data.
Abstract: Interactive statistical graphics are reviewed in the contexts of spatial data and geographical information systems (GIS). GIS provide the user with an active geographical view of the data—a map that can be used as an entry point to the data base. Prototype software—SPIDER—illustrates the possibilities of using statistical graphics as further views of the data, which can be made active and thus provide alternative means of querying the data. These views can be cross-referenced by 'linking'. It is argued that such a system can provide a very rich environment for pursuing exploratory statistical analysis of spatial data.
109 citations
TL;DR: The epsilon band model of digitizing accuracy is used to make estimates of the levels of positional uncertainty and measurement error that is due to digitizing polygon outlines, and results prompt a general discussion of the nature of error in spatial databases.
Abstract: This paper discusses the issues of positional accuracy and measurement error in the context of a large empirical study of landscape change in England and Wales. The epsilon band model of digitizing accuracy is used to make estimates of the levels of positional uncertainty and measurement error that is due to digitizing polygon outlines. The degree of error expected had the same polygons been captured in raster format is then determined. These results prompt a general discussion of the nature of error in spatial databases.
105 citations
TL;DR: The original environmental sensitivity index (ESI) mapping concept for oil spills was developed to assist spill response coordinators in evaluating the potential impact of oil along a shoreline and the allocation of resources during and after a spill as discussed by the authors.
Abstract: The original environmental sensitivity index (ESI) mapping concept for oil spills was developed to assist spill-response coordinators in evaluating the potential impact of oil along a shoreline and the allocation of resources during and after a spill. This paper describes enhancements to the ESI concept which includes: (1) a planimclric basemap derived from SPOT multispectral and/or panchromatic data resampled to 10 × 10 m spatial resolution within ± 5 m root mean square error; (2) information for a shoreline ESI derived from a combination of visual and digital image processing techniques applied to remotely-sensed data; (3) information on oil-sensitive wildlife placed in a geographic information system (GIS) for rapid retrieval and querying; and (4) placing all access and protection information in the GIS and interfacing it with a relational database for rapid access and query. These enhancements to the ESI mapping concept make it more effective for developing contingency plans before an oil spill and ma...
TL;DR: QUILT is a prototype geographic information system (GIS) that uses the quadtree data structure as the underlying representation for cartographic data and provides a simple attribute attachment system which associates non-spatial data with geographic objects.
Abstract: This paper describes QUILT, a prototype geographic information system (GIS) that uses the quadtree data structure as the underlying representation for cartographic data. While QUILT contains many features typically available in a GIS, its primary purpose is to serve as a testbed for the design and testing of new data structures and algorithms for use in computer cartography. Quadtree variants for region, point and line data are implemented using the linear quadtree, organized on disk by a B-tree. QUILT provides a simple attribute attachment system which associates non-spatial data with geographic objects. The user views QUILT as an augmented LISP environment. QUILT's geographic functions include conversion of rasters to and from quadtrees; subset operations to select specified geographic objects; map editing, display, windowing, intersection and union operations; polygon expansion; and computation of geographic object properties such as the centroid, area, perimeter and bounding rectangle for sets of geog...
TL;DR: This paper represents an attempt to combine a geographical information system (GIS) and satellite imagery within a numerical model for the simulation of regional urban growth in France.
Abstract: This paper represents an attempt to combine a geographical information system (GIS) and satellite imagery within a numerical model for the simulation of regional urban growth. The area under study is located in the southeast of France, between the cities of La Ciotat and Toulon. It covers 1600 km2. The spatial resolution of the GIS as well as of the remote sensing data is better than one hectare (80 x 80 m2). Seven environmental parameters are defined by pixel and originate from the content of the database, namely, land use, topography, road network, forest properties and forest fire characteristics. The initial state (year 1976) and the simulated states for the years 2000 and 2025 are compared and the differences are discussed briefly.
TL;DR: A statistical characterization of positional error in manually-digitized and map-registered point data, the relative contribution of point type and operator to digitization error, and the effects of map media type on the positional uncertainty associated with registration are reported on.
Abstract: Digital map coordinates represent the locations of real world entities. As such, differences can exist between the ‘tru’ and digital database coordinates of those entities. This paper reports on a statistical characterization of positional error in manually-digitized and map-registered point data, the relative contribution of point type and operator to digitization error, and the effects of map media type on the positional uncertainty associated with registration. Manually-digitized point data were collected by four operators from mylar and paper maps. Point locations for a number of different feature types were sampled from United States Geological Survey (USGS) 1:24 000 scale maps. Linear models were used to estimate the variance components due to among-operator, map media, point type and registration effects. The statistical distribution of signed distance deviations for manually-digitized data was leptokurtic relative to a random normal variate. Unsigned deviations averaged 0-054 mm. Squared distance ...
TL;DR: The objective is to search digital map databases for the presence of geographical relationships that may be useful for descriptive purposes, as a pointer towards areas for further investigation, and as a means of generating hypotheses for subsequent testing.
Abstract: The paper describes a exploratory procedure for data analysis for use within GIS. The objective is to search digital map databases for the presence of geographical relationships that may be useful for descriptive purposes, as a pointer towards areas for further investigation, and as a means of generating hypotheses for subsequent testing. A prototype Geographical Correlates Exploration Machine (GCEM) is demonstrated by searching for possible linkages between children with leukaemia and a selection of environmental coverages. Arc Info is used for the GIS parts and a Cray X-MP/48 supercomputer for the analysis. Ultimately, it is envisaged that GCEM will be able to run entirely within a GIS workstation environment.
TL;DR: The results show that the best overall techniques are the ones which take advantage of spatial relationships inherent in the data sets and these were the Scan Line algorithm for vector to raster conversions and the Boundary Linking algorithm for raster to vector conversions.
Abstract: This paper examines the common methods for converting spatial data sets between vector and raster formats and presents the results of extensive benchmark testing of these procedures. The tests performed are unique in this field since: (1) they used both synthetic and real test data sets; (2) they measured conversion quality, accuracy and efficiency, not just how fast the procedure operated; and (3) they were conducted in a generic geographic information system (GIS) environment without the aid of specialized computer hardware. The results show that the best overall techniques are the ones which take advantage of spatial relationships inherent in the data sets. These were the Scan Line algorithm for vector to raster conversions and the Boundary Linking algorithm for raster to vector conversions.
TL;DR: The simple method of storing and processing temporal graphical data by the addition of time-encoding attributes to data elements as required to assist a broad range of space/time-related studies is examined.
Abstract: With an ever-increasing number of land information systems being developed, there is a growing demand by users for systems which support the use of temporal data for time-based studies. System managers, however, may have difficulty responding to these calls because of the lack of available research to guide them in their task. This paper examines the simple method of storing and processing temporal graphical data by the addition of time-encoding attributes to data elements as required. To illustrate the technique, a historical digital cadastral database has been created which al lows users to display and report on the cadastral parcellation of a region at any time in the past. The method can also be widely applied to other data to assist a broad range of space/time-related studies.
TL;DR: The problems in teaching a course on geographical information systems in higher education are reviewed and a possible syllabus that will be most relevant to needs in the United Kingdom is suggested.
Abstract: The problems in teaching a course on geographical information systems in higher education are reviewed and a possible syllabus that will be most relevant to needs in the United Kingdom is suggested. The syllabus is divided into six major sections relating to the context, cartographic and spatial analytical concepts, their realization in a computing environment, operations, applications and institutional issues. A particular feature is an attempt to maintain a rigid distribution between underlying theory which is relatively stable and its more volatile operationalization on computers. The paper results from a symposium held in Leicester (U.K.) late in 1988 that brought together nine specialists in the held.
TL;DR: The design, development, implementation, evolution and use of GIMS for land management decision support are described, and tests of the system's ability to predict real-time fire behaviour are provided.
Abstract: A generic geographical information and modelling system (GIMS) has been developed and implemented for 6 million hectares of fire-prone rural land in eastern Australia. Viewed initially as a land management decision support system rather than as a geographical information system (GIS) per se, GIMS provides extensive capabilities for estimating and recording patterns of vegetation and fuel dynamics, analysing the behaviour of fire and its environmental effects, and reviewing strategies for fire control and related issues. The software operates on personal computers via linkage to an indexed, direct access, grid data base. The design, development, implementation, evolution and use of GIMS for land management decision support are described, and tests of the system's ability to predict real-time fire behaviour are provided. The relationship between commercial GIS packages and locally-developed dynamic modelling GIS programs is discussed.
TL;DR: Remedies to the problems of tiles provide a basis for specifying the requirements for sheetlessness in a truly sheetless database, reviewed in a companion paper.
Abstract: A geographic information system (GIS) provides access to information for potentially large areas. Traditionally, cartographers have divided maps into sheets for technical reasons. While such units survive in digital databases, they serve a different function. The 'tile' system has limitations and deficiencies which must be understood by software developers and users. Remedies to the problems of tiles provide a basis for specifying the requirements for sheetlessness. A truly sheetless database depends on indexing algorithms, reviewed in a companion paper.
TL;DR: This paper illustrates how a simple spatial problem, formalised using predicate calculus, may be readily implemented as a rule base in which the production rules represent Horn clauses, a high-level mathematical language capable of expressing the spatial relationships and queries typically handled by a GIS.
Abstract: The application of applied artificial intelligence techniques to geographical data processing has attracted considerable interest in recent years as reflected in the research agendas of major GIS research institutions. This paper illustrates how a simple spatial problem, formalised using predicate calculus, may be readily implemented as a rule base in which the production rules represent Horn clauses. The theoretical significance of this exercise is the search for a high-level mathematical language capable of expressing, in a generic and implementation-independent syntax, the spatial relationships and queries typically handled by a GIS. Of more practical interest is the example it provides of mapping a conventional algorithm into a production rule knowledge structure.
TL;DR: The economic evaluation of implementing a GIS should be considered as a guide to the design and implementation of the system as a whole and not as an excuse for not implementing it.
Abstract: (1990). Concerning ‘The economic evaluation of implementing a GIS’. International Journal of Geographical Information Systems: Vol. 4, No. 2, pp. 203-210.
TL;DR: The principal conclusion is that achieving a widely-accepted method of defining geographic data formats should be an important objective of efforts at standardization.
Abstract: Transferring data from one geographic information system to another commonly requires a sequence of interfaces, software packages that convert data from one format to another. Construction is described of a model interface that uses a relational database management system and compiler-building tools that work from a machine-readable definition of a data format. Parallels are drawn with conversion and translation problems in other areas from which software tools might be obtained for automation of interface construction. Three interfacing strategies are examined. In particular, the advantages and limitations are discussed for the strategy of using a standard interchange format. The principal conclusion is that achieving a widely-accepted method of defining geographic data formats should be an important objective of efforts at standardization.
TL;DR: A regional geographical information system for some Mediterranean benthic communities is described that all its layers describe the same theme but as seen at different moments with different scales and techniques used by different oceanographers.
Abstract: This paper describes a regional geographical information system (GIS) for some Mediterranean benthic communities. The area covered by the GIS lies between the cities of La Ciotat and Giens in southeast France. The distinctive characteristics of this GIS compared with others usually described in the literature, are that all its layers describe the same theme but as seen at different moments with different scales and techniques used by different oceanographers. A method was devised to synthesize, on a pixel basis, the content of all these layers. Each pixel within each layer is weighted with a function relating to the year of survey, the sampling technique and the scale of the original map corresponding to that layer. The synthesis map is composed of the highest weighted values found in the set of layers. Also at each pixel, conflicts between the contents of layers are quantified and mapped.
TL;DR: A reactive data structure is presented here as a modification of the binary space partitioning tree that includes the levels of detail, one of the few spatial data structures that does not organize space in a rectangular manner.
Abstract: We present a reactive data structure, that is, a spatial data structure with detail levels. The two properties, spatial organization and detail levels, are the basis for a geographic information system (GIS) with a multi-scale database. A reactive data structure is a novel type of data structure catering to multiple detail levels with rapid responses to spatial queries. It is presented here as a modification of the binary space partitioning tree that includes the levels of detail. This tree is one of the few spatial data structures that does not organize space in a rectangular manner. A prototype system has been implemented. An important result of this implementation is that it shows that binary space partitioning trees of real maps have O(n) storage space complexity in contrast to the theoretical worst case O(n2 ), with n the number of line segments in the map.
TL;DR: Six currently-available GIS-oriented videotapes are reviewed and an evaluation is made of the usefulness of each in classroom-based GIS instruction.
Abstract: Abstract. The growing interest in teaching about geographic information systems (GIS) raises a number of issues concerning the effectiveness of conventional instructional methods. To convey basic GIS concepts and applications better requires much more emphasis upon visual media. One such medium is that of VHS (or Beta) videotapes. Six currently-available GIS-oriented videotapes are reviewed for this purpose. Their contents are summarized and an evaluation is made of the usefulness of each in classroom-based GIS instruction.
TL;DR: A regression technique is described for obtaining estimates of the manual digitizing effort required during a mapping project and is applied with good results to a set of five maps of varying dimensions and complexity.
Abstract: A regression technique is described for obtaining estimates of the manual digitizing effort required during a mapping project. This technique is then applied with good results to a set of five maps of varying dimensions and complexity. The technique was derived from experience with one geographical information system but may be applicable to others since it has its basis in the physical dimensions of the map.