GIS, MAPS AND VISUALISATION van Der Merwe, F. Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria. E-mail:
[email protected] “The modern age has a false sense of superiority because of the great mass of data at its disposal, but the valid criterion of distinction is rather the extent to which Man knows how to form and master the material at his command. Goethe, 1802” ABSTRACT Whereas cartography is concerned with the representation of static geographical and spatial data, GIS is more concerned with visualisation and analysis tools. GIS does not produce maps in the true sense of the word, while the theory of geographic visualisation is not sufficiently developed to give direction to the GIS development. The difference between maps and visualisation is indicated and the dichotomy of expanded reasoning and personal construction inherent in visualisation is described. Finally a plea is made for a more theoretical approach to visualisation in the cartographic community as opposed to the technology-driven approach forced by the present development of GIS. 1.
INTRODUCTION
Traditional Cartography was, and still is, concerned with the presentation and visualisation of static geographical, or spatially analogous data. The visualisation aspect addresses only the visio-cognitive interpretation of mapping symbols by the cartographer, and users, and the concerns that the interpretations should match. The trend in the literature is to predict that the next steps in the development of more sophisticated tools for cartographic visualisation will come from the use and usefulness of Geographic Information Systems (GIS). (1; 2; 3.). “GIS is popularising cartography… The ‘old’ map in new forms will become a principal medium for communication…” (4) In this essay I will firstly look at conventional maps and cartography, as opposed to the so-called “maps” of GIS and their production. I will show that GIS images are not maps and consequently, due to the constraints and uses of the technology, GIS have contributed very little to map creation. Some future possibilities and directions in which GIS may develop will be considered against the theory of visualisation and the agenda of the ICA Commission on Visualization and Virtual Environments. I will conclude by drawing together the present state of GIS visualisation tools and future development to show that GIS visualisation development should be theory driven. 2.
MAPS, CONVENTIONAL CARTOGRAPHY AND GIS
2.1 Maps The best way to ensure that the description of a spatial relationship evokes a similar image in the listener’s mind, “is to provide a visual representation of the image. This graphic representation of the geographical setting is what we call a map.” (5). Foote and Crum (6) state that “(maps) are the pre-eminent means of recording and communicating information about the location and spatial characteristics of the natural world and of society and culture.” A map, however, is not just an image: Wood (7) explains: “The map image is accompanied by a crowd of signs: titles, dates, legends, keys, scale statements…How these signs come together is the province of a presentational code, which…offers…a structured, ordered, articulated and effective display…” (Emphasis added) Foote and Crum (8) describes a large number of map elements, some that are found on all maps, some that are context sensitive and some that will enhance effective communication. Furthermore, they discuss aesthetic and visual communication elements like balance in the visual hierarchy.
Proceedings of the 21st International Cartographic Conference (ICC) ‘Cartographic Renaissance’ ISBN: 0-958-46093-0
Durban, South Africa, 10 – 16 August 2003 Hosted by The International Cartographic Association (ICA) Produced by: Document Transformation Technologies
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Figure 1. Map Elements and Visual Balance (From Foote and Crum, 1995: Basic Elements of Map Composition). The maps in figure 1 are illustrative of the point and are taken from the article mentioned. Maps consist of a large set of Extrasignificant and Intrasignificant codes (9; 10), the purpose of which is to convey the message of the map overtly and covertly. “(I)t serves as a visual analogue of phenomena, attributes, and spatial relations…”, but also, “…it refers to itself and to its makers and to a world seen quite subjectively through their eyes.” (11). The purpose of the map then, is to use all the powers bestowed upon it by the science and art of cartography, to show the reader as clearly as possible, what the cartographer had in mind. It is, however, a static phenomenon—a rationalised, time bound, graphical representation of a geographical or analogous reality, with explanatory narrative and symbolisation. This explanatory narrative and symbolisation enables us to speak of a road map (analogy to the real roads), mind map (analogy to cognitive schemata) or a website map (analogy to site topology). 2.2 Conventional Cartography Robinson et al (12) sees conventional cartography as “…a series of information transformations, starting with environmental data and ending with an image of the environment in the mind of the map user.” They continue to define the scope of cartography by four processes (13): ! Collecting and selecting the data for mapping. ! Manipulating and generalizing the data, designing and constructing the map. ! Reading or viewing the map. ! Responding to or interpreting the information.” Cartography is therefore a linear process—from interpretation and selection by the cartographer, to selection and interpretation by the user. The theory of cartography, and there is no mean volume of it, is concerned with the process between the end points. To ensure that the user sees what the cartographer intended. Apart from the technology of map-making, the first attempts at theorising about cartography as a science started in World War 2 as part of the military action when an awareness of the functionality of maps became apparent. By the mid 1950’s the science of cartography was seen as analogous to the science of communication and the communication paradigm was established. (14; 15; 16). See Figure 2.
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Figure 2. A Generalised Communication System from Lambrick et al (2002: sect 1 p. 17) also in MacEachren (1995) Studies into vision and visual cognition by, amongst others, S.M. Kosslyn, David Marr and Steven Pinker and the study of the principles of scientific visualisation, of which Edward Tufte is a great exponent, led to the realisation that modern cartography is more than a communication process. Alan M. MacEachren and Menno-Jan Kraak mostly pioneered the new information-processing paradigm of cartography. Figure 3 attempts to crystallise the work of MacEachren (17) in a simple diagram.
Figure 3. A Simplified version of MacEachren's (1995) Information Processing Paradigm of Cartographic Communication. While the information processing view of cartography does not invalidate the older communication process, it augments it to incorporate the workings of the human mind, as it is presently understood, into the process. The purpose of understanding the process is still to enable the user to derive the same meaning from the map as was originally intended by the cartographer. That, after all, is the purpose of a good map. 2.3 Geographical Information Systems (GIS) The history of GIS is well documented from its origins in automated or computer-assisted cartography in the mid 1960’s and can be researced in any reputable GIS textbook. Suffice to say that some of the reasons for GIS’s virtual instantaneous success include “…the early beginnings in a large-scale, very visible, …application; major institutional and commercial interest… the compatibility with the highly respected cartographic tradition in geography; the strong visual orientation and the intuitive appeal of the overlay model in GIS operation…” (18) Definitions of GIS abound and vary from the toolbox type of definition to the organisational emphasis type (19). Most of the definitions include—amongst the hardware, software, data capturing, management, transformation and analysis parts—the display of the data. It is this display, the “…strong visual orientation…” (20), that is the lure in GIS, for laymen and cartographers alike. But what is this display? GIS displays are either of the primary data, or the result of some analysis done with one or more sets of primary data, against a spatial system of reference. GIS display discrete features using points, lines or polygons (Fig.4), or images and sampled grids in raster format (Fig 5), or surfaces in either raster or vector format (Fig.6), or combinations of these. (21)
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Figure 4. Discrete Features.
Figure 5. Images and Sampled Grids.
Figure 6. Surfaces in Raster or Vector Format. These displays are not maps. They are the visual product of some data gathering process or some process of overlay and analysis and, as such, only interpretable by the operator who produced them. They lack all the communicative elements of a map, and, what is more, the software that produced them has very little capability to turn them into maps. “Most GIS have limited capacity to display symbols” (22). “Ordinal and higher scales (of measurement) require magnitude to be displayed and this is where many GIS fall down.” (23) “Texture density is difficult to control is often not available on GIS…” (24) “GIS have limited typographic facilities.” (25) “The summary… of GIS cartographic capabilities shows that, at present, GIS are, in general, far from being able to meet the standard of conventional cartography.” (26) The prospects of incorporating the GIS images into maps are becoming increasingly better with “…many vendors developing special mapping tools which are linked to or integrated within the GIS database. The results are maps of high cartographic quality” (27) (emphasis added). It can only be concluded that GIS do not produce maps and contributed very little, if anything, to the advancement of map creation. The theory of GIS lies in planning and quantitative geography. The theory and science of maps are firmly grounded in cartography, not in GIS. Lambrick et al (28) state in their introduction to section 7 that “(s)omething like 90% of maps may now be being (sic) produced by non-cartographers.” I contend that very few of those are maps, or conform to the standards of a map. Most are simply GIS images. If not a map, what then are these GIS images? I contend that they are a form of graphic depiction of the data, enabling the user to think about the data better. A form of scientific visualisation. 3.
THE NATURE OF VISUALISATION
MacEachren (29) offers “…a three dimensional model of human-map interaction space that defines what might be considered prototypes for visualization and communication. The dimensions of the interaction space are defined by three continua: from map use that is private (tailored to an individual) to public (designed for a wide audience); map use
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that is directed toward revealing unknowns (exploration) versus presenting knowns (presentation); and map use that has high interaction versus low interaction.” Figure 7 is from that source and copied from Keightly (30).
Figure 7. MacEachren's Human-map Interaction space. While MacEachren’s model may be sufficient to depict human-map interaction, it may be a submodel of a larger set governing the total field of visualisation. That activity of humans that enable them to display thoughts, data, information and even stories in images, whether it be in the mind’s eye or in physical format. Intuitively one can feel that there must be basic visualisation principles common to looking at a statue, a painting, a map, an interactive multimedia presentation, a graph, a GIS image of a DEM and a mental vision of what a room will look like after a new coat of paint. The continuum of visualisation, from public to private use, in a geographical context, can be depicted as in Figure 8. Although the categories, static images, interactive visualisation and mental visualisation are depicted as separate, the boundaries between them are fuzzy and the range is actually continuous and interactive. The diagram indicates the main uses of the different categories, although the boundaries are also fuzzy.
Figure 8. Categories of Visualisation. Visualisation is the mental and physical process of graphically representing a set, or sets, of data and using the very broadband channel of human visual information flow, the human pattern recognition abilities and the human access to a rich cognitive structure for imparting hypotheses, explanations and theories pertaining to the causal processes inherent in the data. Visualisation can be used to inform, to inquire or as part of the thinking process itself. (31; 32; 33)
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Visualisation is about “…pictures of numbers…pictures of nouns…pictures of verbs, the representation of mechanism and motion, of process and dynamics, of causes and effect, of explanation and narrative” (34) Encyclopaedia Britannica (35) sees one of the elements of computer graphics as “scientific visualization, in which simulations of scientific events—such as the birth of a star or the development of a tornado—are exhibited pictorially and in motion so as to provide far more insight into the phenomena than would tables of numbers. (emphasis added) “It is important to differentiate between scientific visualization and presentation graphics. Presentation graphics is primarily concerned with the communication of information and results in ways that are easily understood. In scientific visualization, we seek to understand the data. However, often the two methods are intertwined.” (36) 3.1 The Epistemology of Visualisation The epistemology of scientific, and for that matter, cartographic visualisation, is essentially constructionist. MacEachren, inter alia, describes how each individual’s understanding of what is seen is the product, or construction, of the interaction between vision, cognition and the individual’s own cognitive schemata. See figure 3. Each person’s interpretation, or knowledge gained from a map or graphic, is therefore to a large extent dependent on available schemata or prior knowledge, which again is a product of culture and acculturation. This constructionist approach is also a limiting factor in the visualisation of new knowledge, since most of what is seen will tend to be grouped or categorised into existing knowledge schemata. The same argument holds for the creation of maps or graphics. It is easier to design graphical outputs along known lines than to produce unique, insightful visualisations. Because of the limitations it is imperative that the same modus operandi, which is evident in scientific thinking, be brought to bear on visualisations. These include “…documenting the sources and characteristics of the data, insistently enforcing appropriate comparisons, demonstrating mechanisms of cause and effect, expressing those mechanisms quantitatively, recognizing the inherently multivariate nature of analytic problems and inspecting and evaluating alternative explanations.” (37) 3.2 Modes of Reasoning Although inference in visualisation uses the normal modes of reasoning, i.e. deduction, locating pre-defined patterns, and induction, generalising from examples, a third mode of reasoning namely abduction is added. (38). Abduction, first coined by C.S. Peirce, the father of Pragmatism in 1878, is the “…creative formulation of new statistical hypotheses that explain a given set of facts,” (39) (emphasis added) Abduction is seen as the initial approach in especially exploratory visualisation, since it “…is flexible because it is not restricted to using existing knowledge structures (e.g. categories) but is instead free to create new structures that help to explain the data presented.” (40) It is also the method used for generating Tufte’s alternative explanations. Visualisation for scientific (geographic) enquiry is therefore an expansion of our existing scientific method, but it is also uniquely personal and therin lies a dichotomy. Visualisation is not just an expansion of cartographic principles. The theory of visualisation is a larger set of principles, probably encompassing cartography, much like Einstein’s relativity theory encompasses Newton’s laws of motion (41), but not necessarily deducible from the principles of cartography. 4.
FUTURE DEVELOPMENTS OF GIS
GIS is not in the business of cartography, but it is firmly settled in the business of visualisation. “The use of GIS is the next logical step toward increasing a more user specific application where analysis and exploration of a more specific data set foster increased private thinking and the uncovering of unknowns.” (42) A “… recent (and continuing) development is the increase in speed of PCs, as well as the reduction in cost of high end workstations. This is bringing the world of Scientific Visualization to every possible user.” (43.). Statements like those above abound in the literature on the development of scientific visualisation and GIS. Lambrick et al (44) cite better rendering, animation, 3-D visualisation and virtual reality as important developments for GIS in the future, and especially for improving their visualisation capabilities. While it is an undeniable fact that technological advances have brought much more powerfull computing and graphics display tools to the toolbox, and will continue to do so with increasing rapidity in the foreseeable future, it is also an undeniable fact that our understanding of our interaction with the tools is limited.
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Keightley (45) contends, “(v)isualisation in the digital world is clearly more complex than with the paper map.” Added to this complexity are the intricacies of data manipulation, transformation and analyses in GIS. A research spearhead that may address the problem in the visualisation area is the research into Geographic Visualisation (GVis) principles and tools. MacEachren and Kraak (46) state that “The current model deemphasizes the tension between a communication and visualization approach to cartography by treating geographic visualization (GVis) as a superset that includes attention to effective presentation, but expands the bounds of geoinformation use well beyond … cartographic communication”, which confirms my earlier thesis. Although their definition may be limiting, it may be adequate for GIS development. Another field of research which I consider of prime importance in the context of GIS, maps and visualisation, is that of GIS/Visualisation integration. “Traditional GIS environments have treated visual display as an output, thus an endpoint of a query or analysis process. GVis,…emphasizes information exploration and hypothesis generation, thus it is as likely to produce queries as be the result of one. For GVis to reach its potential, a new view of both GIS and GVis system design is required. Research must address the range of issues associated with merging the goals and functions of GIS and GVis.” (47) See also Fairbairn et al, (48); Cartwright et al, (49) and Slocum et al, (50) Thus, while “(t)he ‘old’ map in new forms will become a principal medium for communication…” (51) may still be true, the main thrust of GIS will most likely not be presentation, but visualisation and enquiry, especially if one considers the proliferation of GIS in disciplines other than traditional geography, geology and planning fields. 5.
CONCLUSIONS
GIS have never been used to produce maps in the true sense of the word. The true maps that are being produced using GIS output, are presently being produced with auxiliary software like desktop publishing packages or computer cartography software. In the light of the development of GIS thus far, I do not see GIS developing competent cartographic display packages. Technical, as opposed to technological, research takes us into animation, 3-D images and space-time representations; in the direction of visualisation tools for enquiry, but haphazardly so. Therein lies the catch. In our delight with Couclelis’ strong visual orientation combined with our confusion between presentation graphics and scientific visualisation, of which GVis is a subset. Keightley (52) realises that “… throughout all techniques it is the deconstructed format of single theme data that inhibits exploratory visualisation.” Tufte talks about “recognizing the inherently multivariate nature of analytic problems and…inspecting and evaluating alternative explanations.” Gahegan et al talks about an expanded paradigm of the scientific method. Just when we become elated at all this new science MacEachren and Kraak (53) puts a damper on it: “There is little systematically collected empirical evidence to either support or refute the claim (that visualization will facilitate science) and we know relatively little about how scientists actually use sophisticated visualization tools and methods.” My argument is, as I have shown, that visualisation is a complex subject with an inherent epistemological dichotomy, an expanded mode of reasoning and a continuous thread with sharp changes of focus between the eminently physical and the mentally abstract. GIS are inherently complicated systems with a myriad skills required from the operator, from data capture to intelligent analyses. A marriage of the two without a proper theoretical foundation will be tantamount to willy-nilly trying out haphazard technical advances in graphics. We must strive “…to develop fundamental ideas leading to general tools for real applications.” (54) (emphasis added) 6. [1] [2] [3] [4] [5]
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Foote, E. and Crum, S., 1995: Cartographic Communication, The Geographer’s Craft Project, Department of Geography, University of Colorado at Boulder. http://www.colorado.edu/geography/gcraft/notes/cartocom/cartocom_f.html Wood, D., 1992: The Power of Maps, The Guildford Press, New York, p. 131. Foote, E. and Crum, S., 1995: Cartographic Communication, The Geographer’s Craft Project, Department of Geography, University of Colorado at Boulder. http://www.colorado.edu/geography/gcraft/notes/cartocom/cartocom_f.html MacEachren, Alan M. 1995: How Maps Work: Representation, Visualisation and Design, The Guildford Press, New York. Wood, D., 1992: The Power of Maps, The Guildford Press, New York. Wood, D., 1992: The Power of Maps, The Guildford Press, New York, p. 116. Robinson, A.H., Morrison, J.L., Muehrcke, P.C., Kimerling, A.J. and Guptill, S.C., 1995: Elements of Cartography, 6th edition, John Wiley and Sons Inc., New York, p. 9. Robinson, A.H., Morrison, J.L., Muehrcke, P.C., Kimerling, A.J. and Guptill, S.C., 1995: Elements of Cartography, 6th edition, John Wiley and Sons Inc., New York, p. 18. MacEachren, Alan M. 1995: How Maps Work: Representation, Visualisation and Design, The Guildford Press, New York. Robinson, A.H., Morrison, J.L., Muehrcke, P.C., Kimerling, A.J. and Guptill, S.C., 1995: Elements of Cartography, 6th edition, John Wiley and Sons Inc., New York. Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria. MacEachren, Alan M. 1995: How Maps Work: Representation, Visualisation and Design, The Guildford Press, New York. Couclelis, H., 1998: Geocomputation in Context, in Longley, P.A., Brooks, S.M., McDonnell, R. and MacMillan, B. (eds.), Geocomputation: A Primer, Wiley, Chichester, p. 19 Burrough, P.A. and McDonnell, R.A., 1998: Principles of Geographical Information Systems, Oxford University Press, Oxford. Couclelis, H., 1998: Geocomputation in Context, in Longley, P.A., Brooks, S.M., McDonnell, R. and MacMillan, B. (eds.), Geocomputation: A Primer, Wiley, Chichester, p. 19 Zeiler, M., 1999: Modeling Our World: The ESRI Guide to Geodatabase Design, ESRI Press, Redlands. Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7, p. 2 Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7, p. 2. Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7, p. 3. Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7, p. 4. Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7, p. 5. Burrough, P.A. and McDonnell, R.A., 1998: Principles of Geographical Information Systems, Oxford University Press, Oxford, p. 92 Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7. MacEachren, Alan M. 1995: How Maps Work: Representation, Visualisation and Design, The Guildford Press, New York, p. 358. Keightley, E., n.d.: The Cube http://www.gisca.adelaide.edu.au/~ekeightl/vis/05cube.html, The National Key Centre for Social Applications of GIS (GISCA), University of Adelaide, Adelaide. MacEachren, Alan M. 1995: How Maps Work: Representation, Visualisation and Design, The Guildford Press, New York. Gahegan, M, Wachowicz, M, Harrower, M and Rhyne, T, 2000: The Integration of Geographic Visualization with Knowledge Discovery in Databases and Geocomputation, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/icavis/pdf/knowledge0900.pdf
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Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria. Tufte, E.R., 1997: Visual Explanations: Images and Quantities, Evidence and Narrative, Graphics Press, Cheshire, Connecticut, p. 10. Encyclopaedia Britannica, 2002: De Luxe edition CD ROM, Encyclopaedia Britannica, Inc. Scientific Visualisation Tutorials, n.d.: Scientific Visualization Laboratory, Educational Technologies Directorate, OITGeorgia Institute of Technology. http://www.cc.gatech.edu/scivis/tutorial/linked/infuture.html Tufte, E.R., 1997: Visual Explanations: Images and Quantities, Evidence and Narrative, Graphics Press, Cheshire, Connecticut, p. 53. Gahegan, M, Wachowicz, M, Harrower, M and Rhyne, T, 2000: The Integration of Geographic Visualization with Knowledge Discovery in Databases and Geocomputation, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/icavis/pdf/knowledge0900.pdf Flew, A., 1999: A Dictionary of Philosophy, Revised Second Edition, Gramercy Books, New York, p. 1. Gahegan, M, Wachowicz, M, Harrower, M and Rhyne, T, 2000: The Integration of Geographic Visualization with Knowledge Discovery in Databases and Geocomputation, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/icavis/pdf/knowledge0900.pdf , p.5. Einstein, A., 2002 (1916): Relativity, Routledge Classics, Routledge, London. Keightley, E., n.d.: Mapping Technology http://www.gisca.adelaide.edu.au/~ekeightl/vis/07maptec.html, The National Key Centre for Social Applications of GIS (GISCA), University of Adelaide, Adelaide. Scientific Visualisation Tutorials, n.d.: Scientific Visualization Laboratory, Educational Technologies Directorate, OITGeorgia Institute of Technology. http://www.cc.gatech.edu/scivis/tutorial/linked/infuture.html Lambrick, D., Van Helden, P. and Booysen, I., 2002: Visualisation and Spatial Thinking, UNI 790 Course Notes in HTML and PDF formats, Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria, Section 7. Keightley, E., n.d.: The Digital World http://www.gisca.adelaide.edu.au/~ekeightl/vis/06dig.html, The National Key Centre for Social Applications of GIS (GISCA), University of Adelaide, Adelaide. MacEachren, A. M. and Kraak, M., 1999: Terms Of Reference 1999-2003, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/sites/icavis/agenda.html MacEachren, A. M. and Kraak, M., 1999: Terms Of Reference 1999-2003, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/sites/icavis/agenda.html Fairbairn, D., Andrienko, G., Andrienko, N., Buziek, G. and Dykes, J., 2000:Representation and its relationship with cartographic visualization: a research agenda, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/sites/icavis/agenda/PDF/Fairbairn.pdf Cartwright, W., Crampton, J., Gartner, G., Miller, S., Mitchell, K., Siekierska, E. and Wood J., 2000: Geospatial Information Visualisation User Interface Issues, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/sites/icavis/agenda/PDF/Cartwright.pdf Slocum, T.A., Block, C., Jiang, B., Koussoulako, A., Montello, D.R., Fuhrmann, S. and Hedley, N.R., 2000: Cognitive and Usability Issues in Geovisualization, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/sites/icavis/agenda/PDF/SlocumLong.pdf Robinson, A.H., Morrison, J.L., Muehrcke, P.C., Kimerling, A.J. and Guptill, S.C., 1995: Elements of Cartography, 6th edition, John Wiley and Sons Inc., New York, p. 311. Keightley, E., n.d.: Geographic Information Systems http://www.gisca.adelaide.edu.au/~ekeightl/vis/08gis.html, The National Key Centre for Social Applications of GIS (GISCA), University of Adelaide, Adelaide. MacEachren, A. M. and Kraak, M., 1999: Terms Of Reference 1999-2003, ICA Commission on Visualization and Virtual Environments: Research Agenda, http://www.geovista.psu.edu/sites/icavis/agenda.html Scientific Visualisation Tutorials, n.d.: Scientific Visualization Laboratory, Educational Technologies Directorate, OITGeorgia Institute of Technology. http://www.cc.gatech.edu/scivis/tutorial/linked/infuture.html
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GIS, MAPS AND VISUALISATION van Der Merwe, F. Department of Geography, Geoinformatics and Meteorology, University of Pretoria, Pretoria. E-mail:
[email protected] Biography Fritz van der Merwe was born in the Free State town of Ficksburg. He matriculated at Grey Colledge in Bloemfontein in 1969. After school he joined the SA Navy where he served for a couple of years before commencing his studies at the University of Pretoria for a B.Land Surveying degree. In 1982 he registered as a professional Land Surveyor and worked in private practise until 1989 when he joined a survey instrument marketing company. As technical director of the company he was instrumental in getting the first GPS survey receivers operational in South Africa and resposible for getting a number of the first GPS surveys done. He joined the University of Pretoria in 1991 as a lecturer in Land Surveying and in 1996 became part of the Center for Geoinformation Science at the University. He currently lectures in Cartography and Spatial Data Analysis, while his research interests are Visualisation and Cognitive Maps.
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