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All Outputs (21)

The Visvalingam algorithm metrics, measures and heuristics (2016)
Journal Article
Visvalingam, M. (2016). The Visvalingam algorithm metrics, measures and heuristics. The Cartographic journal, 53(3), 242-252. https://doi.org/10.1080/00087041.2016.1151097

This paper provides the background necessary for a clear understanding of forthcoming papers relating to the Visvalingam algorithm for line generalization, for example on the testing and usage of its implementations. It distinguishes the algorithm fr... Read More about The Visvalingam algorithm metrics, measures and heuristics.

A computer science perspective on the bendsimplification algorithm (1999)
Journal Article
Visvalingam, M., & Herbert, S. (1999). A computer science perspective on the bendsimplification algorithm. Cartography and Geographic Information Science, 26(4), 253-270. https://doi.org/10.1559/152304099782294177

The primary aim of this study was to evaluate whether the use of bends provides a better basis than point elimination for research on line structuring. These investigations were undertaken using Arc/Info 7.1.1. Comparative experimental results sugges... Read More about A computer science perspective on the bendsimplification algorithm.

Deconstruction of fractals and its implications for cartographic education (1999)
Journal Article
Visvalingam, M. (1999). Deconstruction of fractals and its implications for cartographic education. The Cartographic journal, 36(1), 15-29. https://doi.org/10.1179/caj.1999.36.1.15

The research reported here was designed for two reasons: firstly, to involve anyone with an interest in cartographic visualization to participate in eliciting cartographic knowledge and to provide them with the opportunity to contribute their practic... Read More about Deconstruction of fractals and its implications for cartographic education.

A cognitive approach to road recognition with novel feature indicators (1996)
Journal Article
Varley, D., Visvalingam, M., & Wright, C. (1996). A cognitive approach to road recognition with novel feature indicators. Computer Journal, 39(9), 751-756. https://doi.org/10.1093/comjnl/39.9.751

This paper outlines a simple strategy for recognition of prototypical cases of urban roads from their outline forms alone. Two new form indicators, namely exits and occupancy, are used together with average width to label regions as roads. They prove... Read More about A cognitive approach to road recognition with novel feature indicators.

Simplification and generalization of large scale data for roads : a comparison of two filtering algorithms (1995)
Journal Article
Visvalingam, M., & Williamson, P. J. (1995). Simplification and generalization of large scale data for roads : a comparison of two filtering algorithms. Cartography and Geographic Information Science, 22(4), 264-275. https://doi.org/10.1559/152304095782540249

This paper reports the results of an in-depth study which investigated two algorithms for line simplification and caricatural generalization (namely, those developed by Douglas and Peucker, and Visvalingam, respectively) in the context of a wider pro... Read More about Simplification and generalization of large scale data for roads : a comparison of two filtering algorithms.

Line generalisation by repeated elimination of points (1993)
Journal Article
Visvalingam, M., & Whyatt, J. D. (1993). Line generalisation by repeated elimination of points. The Cartographic journal, 30(1), 46-51. https://doi.org/10.1179/000870493786962263

This paper presents a new approach to line generalisation which uses the concept of ‘effective area’ for progressive simplification of a line by point elimination. Two coastlines are used to compare the performance of this, with that of the widely us... Read More about Line generalisation by repeated elimination of points.

Cartographic Algorithms: Problems of Implementation and Evaluation and the Impact of Digitising Errors (1991)
Journal Article
Whyatt, J. D., & Visvalingam, M. (1991). Cartographic Algorithms: Problems of Implementation and Evaluation and the Impact of Digitising Errors. Computer graphics forum : journal of the European Association for Computer Graphics, 10(3), 225-235. https://doi.org/10.1111/1467-8659.1030225

Cartographic generalisation remains one of the outstanding challenges in digital cartography and Geographical Information Systems (GIS). It is generally assumed that computerisation will lead to the removal of spurious variability introduced by the s... Read More about Cartographic Algorithms: Problems of Implementation and Evaluation and the Impact of Digitising Errors.

The Douglas-Peucker algorithm for line simplification: Re-evaluation through visualization (1990)
Journal Article
Visvalingam, M., & Whyatt, J. D. (1990). The Douglas-Peucker algorithm for line simplification: Re-evaluation through visualization. Computer graphics forum : journal of the European Association for Computer Graphics, 9(3), 213-225. https://doi.org/10.1111/j.1467-8659.1990.tb00398.x

The primary aim of this paper is to illustrate the value of visualization in cartography and to indicate that tools for the generation and manipulation of realistic images are of limited value within this application. This paper demonstrates the valu... Read More about The Douglas-Peucker algorithm for line simplification: Re-evaluation through visualization.

Trends and concerns in digital cartography (1990)
Journal Article
Visvalingam, M. (1990). Trends and concerns in digital cartography. Computer aided design, 22(3), 115-130. doi:10.1016/0010-4485(90)90070-s

Digital cartography is the technology concerned with the construction and use of computer-based systems for the practice of cartography and its applications. The paper starts with a brief introduction to cartography and cartographic maps. It then pro... Read More about Trends and concerns in digital cartography.

Cartography, GIS and maps in perspective (1989)
Journal Article
Visvalingam, M. (1989). Cartography, GIS and maps in perspective. The Cartographic journal, 26(1), 26-32. doi:10.1179/caj.1989.26.1.26

The signed Chi-score measure for the classification and mapping of polychotomous data (1981)
Journal Article
Visvalingam, M. (1981). The signed Chi-score measure for the classification and mapping of polychotomous data. The Cartographic journal, 18(1), 32-43. https://doi.org/10.1179/caj.1981.18.1.32

Several polychotomous characteristics, when expressed in chi-score form, exhibit distributions in property space which deviate from the inherent assumptions of the more commonly used methods of cluster analysis. This paper suggests a novel approach t... Read More about The signed Chi-score measure for the classification and mapping of polychotomous data.

Making a national atlas of population by computer (1980)
Journal Article
Rhind, D. W., Evans, I. S., & Visvalingam, M. (1980). Making a national atlas of population by computer. The Cartographic journal, 17(1), 3-11. https://doi.org/10.1179/caj.1980.17.1.3

This paper describes the conceptual and practical problems encountered and solved in producing a multi-colour atlas of population characteristics in Great Britain. The atlas itself is in A4 format; it consists of some thirty-four maps of Great Britai... Read More about Making a national atlas of population by computer.

The signed Chi-square measure for mapping (1978)
Journal Article
Visvalingam, M. (1978). The signed Chi-square measure for mapping. The Cartographic journal, 15(2), 93-98. https://doi.org/10.1179/caj.1978.15.2.93

When interest extends beyond purely univariate considerations there is no fixed rule governing the ordering of spatial samples for mapping and statistical analysis. Ratios and numerical differences have conventionally been the basis for comparing sam... Read More about The signed Chi-square measure for mapping.

Indexing with coded deltas—a data compaction technique (1976)
Journal Article
Visvalingam, M. (1976). Indexing with coded deltas—a data compaction technique. Software: Practice and Experience, 6(3), 397-403. https://doi.org/10.1002/spe.4380060313

The paper describes the coded delta scheme, which is one of the methods used by the Census Research Unit, University of Durham, for compacting the 1971 U.K. census data. It evaluates the merits and limitations of the technique in relation to the char... Read More about Indexing with coded deltas—a data compaction technique.

Well-point techniques and the shallow water table in boulder clay (1974)
Journal Article
Visvalingam, M., & Visvalingam, M. (1974). Well-point techniques and the shallow water table in boulder clay. The Journal of soil science, 25(4), 505-516. https://doi.org/10.1111/j.1365-2389.1974.tb01145.x

The reliability of water-table measurements in clay soil is currently under review (Twocock, 1971; Bonell, 1971; Visvalingam, 1972). This paper summarizes some of the experimental results from a boulder clay catchment in East Yorkshire. The experimen... Read More about Well-point techniques and the shallow water table in boulder clay.

The neutron method for measuring soil moisture content - a review (1972)
Journal Article
Visvalingam, M., & Tandy, J. D. (1972). The neutron method for measuring soil moisture content - a review. The Journal of soil science, 23(4), 499-511. https://doi.org/10.1111/j.1365-2389.1972.tb01680.x

THE various methods of measuring the soil moisture content and its variations in space and time have been reviewed by many authors (Taylor, 1955; Marshall, 1959; Todd, 1960; Ballard and Gardner, 1965; Cope and Trickett, 1965). The moisture content is... Read More about The neutron method for measuring soil moisture content - a review.

Deviation of the Sungei Mulia (1970)
Journal Article
Visvalingam, M. (1970). Deviation of the Sungei Mulia. Geographica : journal of the Department of Geography, and Geographical Society, University of Malaya, Kuala Lumpur, 6, 123-129

Changes in land use triggering the instability of canalised river channels in padi fields in the Gombak Valley, Selangor, Malaysia.