Editorial

Abstract

Introduction

The Issues

Dynamic mapping tools

cdv

Alternatives to choropleth maps

Conclusions

Future directions

Acknowledgements

References

Case Studies Index

9. Select Bibliography

Anselin, L. (1995) Local indicators of spatial association - LISA. Geographical Analysis, 27: 93-115.
A key paper for anyone interested in local indicators.

Bailey, T.C. and A.C. Gatrell (1995) Interactive Spatial Data Analysis. Harlow: Longman.
Not primarily about visualisation, but an excellent introduction to the statistical methods that are nowadays applied to spatial data.

Baxter, R.S. (1974) Some methodological issues in computer drawn maps. The Cartographic Journal, 13: 145-155.
An early paper that covers much of the ground covered in this Case Study.

Bertin, J. (1983) Semiology of Graphics. Madison: University of Wisconsin Press.

Borden D. Dent (1985) Cartography: Thematic Map Design. Dubuque IA: Wm.C.Brown:
Of the very large number of basic cartography texts, this is highly recommended. Chapter 6 provides a detailed account of the problems in choropleth mapping.

Brewer C.A., 1994, Colour use and guidelines for mapping and visualization. In MacEachren, A.M., & Taylor, D. R. F. (eds) Visualization in Modern Cartography, Oxford: Pergamon, p. 123-147.
A very careful analysis of colour use on maps and graphics, highly recommended.

Census Research Unit (1980) People in Britain: a census Atlas. London: HMSO
This was a very innovative product for its time, making use of the signed chi-square to show area value relative to national expectations and what at the time was very new high resolution laser colour printing technology. Such technology is now commonplace.

Crawford, P.V. (1973) The perception of graduated squares as cartographic symbols. The Cartographic Journal, 10: 85-88.
This is typical of the literature dealing with how map users 'read' symbol types.

Dobson, M.W. (1973) Choropleth maps without class intervals?: a comment. Geographical Analysis, 5: 358-360.
Presents the view that choropleth maps should classify their data into bins.

Dobson, M.W. (1974) Refining legend values for proportional circle maps. Canadian Cartographer, 11: 45-53.

Dorling, D. (1995) A New Social Atlas of Britain. London: John Wiley and Sons.
An extended essay in cartographic visualisation making very effective use of a population area cartogram base to map various social indicators. The philosophy and some code for this are both detailed in:

Dorling, D. (1996) Area Cartograms: Their Use and Creation. Concepts and Techniques in Modern Geography, 59, 69 pages. Norwich: Geobooks.

Dykes, J.A. (1996) Dynamic maps for spatial science: A unified approach to cartographic visualization. In Parker, D. (ed) Innovations in GIS 3, London: Taylor & Francis, London, 177-187.
An introduction to Tcl/Tk for dynamic cartography.

Dykes, J.A. (1997a) Exploring spatial data representation with dynamic graphics, Computers and Geosciences , 23: 345-370
A WWW based paper addressing dynamic means of representation, with interactive examples of dynamic cartography.

Dykes, J.A. (1997b) cdv: a flexible approach to ESDA with free demonstration software. Proceedings, British Cartographic Society, 34^th Annual Symposium, L:eicester, 100-107
Includes a WWW-based interactive example demonstrating Bertin's visual variables in Tcl/Tk.

Evans, I.S. (1976) The selection of class intervals. Transactions of the Institute of British Geographers, 2: 98-124.
An absolutely classic paper that should be compulsory reading for all would-be choropleth mappers. Evans draw attention to the need to make the classification scheme used suit the statistical, possibly also the spatial, distribution of the data being mapped.

Ferreira, J., Jr., and Wiggins, L.L., 1990, The density dial: A visualization tool for thematic mapping. Geo Info Systems, 10: 69-71.
An example of the use of interaction better to design choropleth class intervals.

Flannery, J.J. (1977) The effectiveness of some common graduated point symbols in the presentation of quantitative data. Canadian Cartographer, 8: 96-109.
In order to correct for the perceptual underestimation of the size of large circles, 'Flannery's law' suggests an adjustment to the relationship between the area of a circle symbol and the value it represents.

Fotheringham, A.S., Charlton, M.E. and Brunsdon, C. (1996) The geography of parameter space: an investigation into spatial non-stationarity. International Journal of Geographical Information Systems, 10: 605 - 627.

Getis, A. and Ord J.K. (1992) The analysis of spatial association by use of distance statistics. Geographical Analysis, 24: 189 - 206.

Both the above deal with extensions to the LISA idea.

Kennedy, S. (1994) Unclassed choropleth maps revisited: some guidelines for the construction of unclassed and classed choropleth map. Cartographica, 31: 15-25.

Langford, I (1994) Using empirical Bayes estimates in the geographical analysis of disease risk. Area, 26: 142-190.
A clear, how to do it, account of using Bayes' theorem to modify mapped values according to how well they are known.

Langford, M and Unwin, D.J. (1992) Generating and mapping population density surfaces within a geographical information system. The Cartographic Journal, 31: 21-26.
Shows how careful use of ancillary information can enhance choropleth mapping by allowing dasymetric mapping.

MacEachren, A. M., 1995, How maps work: representation, visualization and design. New York: The Guildford Press.

McCormick, B.H., DeFanti, T.A., and Brown, M.D. (eds) (1987) Visualization in Scientific Computing, Computer Graphics, 21(6), special issue.

Marshall, R.J. (1991) Mapping disease and mortality rates using empirical Bayes estimators. Applied Statistics, 40: 283-294.

Martin, D. (1989) Mapping population data from zone centroid locations. Transactions, Institute of British Geographers, 14: 90-97

Mersey, J.E., 1990, Colour and thematic map design: the role of colour scheme and map complexity in choropleth map communication. Cartographica, 27, Monograph 41, 157 pages.

Monmonier, M. (1989) Geographic brushing: enhancing exploratory analysis of the scatterplot matrix. Geographical Analysis, 21: 81-84.
Early examples of geographic brushing where polygons and scatter plots are linked.

Monmonier, M. (1991) How to Lie with Maps. Chicago & London: Chicago University Press
Based on Huff's well-known book How to Lie with Statistics, this shows how cartography can be used to create false impressions. Chapter 10, Color: Attraction and Distraction should be compulsory reading for those new to the field.

Moore K.M, Wood, J.D. & Dykes, J.A., 1997, Using java to interact with geo-referenced VRML within a virtual field course, ICA Visualization Commission, Gavle, Sweden, June 1997, http://www.geog.le.ac.uk/mek/usingjava.html

Muehrcke, P. (1990) Cartography and geographic information systems, Cartography and Geographic Information Systems, 17: 81-84.

Muller, J.C. (1979) Perceptions of continuously shaded maps. Annals, Association of American Geographers, 69: 240-249
Examines how users perceive continuous choropleth maps and concludes they are able to understand them.

Ord, J.K. and Getis, A. (1995) Local spatial autocorrelation statistics: distributional issues and an application. Geographical Analysis, 27: 286-306.

Ousterhout, J.K. (1994) Tcl and the Tk Toolkit, Addison-Wesley, Reading, Ma., 480p
Tcl/Tk creator and guru introduces the Tcl scripting language and Tk graphical toolkit.

Petersen,M.P (1979) An evaluation of unclassed cross-line choropleth mapping. American Cartographer, 6: 22-23.

Stuetzle, W., 1988, Plot windows. In Cleveland, W.S. and McGill, M.E. (eds), Dynamic graphics for statistics. Belmont CA: Wadsworth Inc., p. 225-245.

Tobler, W.R. (1973) Choropleth maps without class intervals. Geographical Analysis, 5: 26-28.

Tobler's paper first introduced classless choropleth maps of the sort that are nowadays often the default option in software. Petersen's paper evaluates their use in practice.

Unwin, D.J. (1981) Introductory Spatial Analysis. London: Methuen
A dated account of basic spatial statistical analysis that deals with visualisation issues.

Wegman, E.J. (1990) Hyperdimensional data analysis using parallel coordinates. Journal of the American Statistical Association, 85: 664-675.
Excellent introduction to and account of using parallel co-ordinates to analyse and interpret multidimensional data distributions.

Wright, J.K (1933) A method of mapping densities of population with Cape Cod as an example. Geographical Review, 26: 103-110.

10. Other Related Resources.
There are significant additional resources available from the JISC/NTI Project ARGUS, notably a set of WWW pages hosted on the MIDAS service and some other public domain map/Visc packages such as MANET (from University of Augsburg), X-Gobi (from USA) and X-LISP-STAT (see Brunsdon, 1997). A further Case Study in this volume by Wise, Haining and Signoretta reviews and evaluates some of these.

List of WWW Locations