|Dorling, D. (1991) The Visualization of Spatial Structure, PhD Thesis, Department of Geography, University of Newcastle upon Tyne|
Introduction: Human Cartography
|I||Two images from the infinity of the Mandelbrot set (Colour).|
|II||Land use close-up of Northern Britain (Colour).|
|III||Journey to work flows of over ten people between wards from the 10% sample.|
|IV||The changing distribution of housing by price, attributes and sales, 1983-1987.|
|V||Migration flows between all regions in 1976 — flows sorted by contiguity order.|
|VI||Yearly migration flows between English and Welsh wards 1980/1981.|
|VII||The changing distribution of age and gender in Britain 1971-1981 (Colour).|
|VIII||Voting composition on the electoral cartograms of Northern Britain (Colour).|
|IX||Voting composition on the electoral cartograms of Southern Britain (Colour).|
|X||The distribution of employment by industry, status and gender (Colour).|
1 The advantage of maps is simple — they provide context:
Maps frown upon the isolation of single items. They preserve the continuity of the real world. They show things in their surroundings and therefore call for more active discernment on the part of the user, who is offered more than he came for; but the user is also being taught how to look at things intelligently. One aspect of looking at things intelligently is to look at them in context. [Arnheim R. 1976 p.5]
2 [a] The search for a definition of "maps" never ceases:
The current definition of cartography is inadequate largely because it does not define clearly the focus of the subject, namely maps. The description of maps is circular — "maps may be regarded as including all types of maps, charts, sections ...". This implies two types of maps, namely a subclass of specific forms, called maps, and a superclass of generic forms also called maps. The subclass of maps is defined as a "representation, normally to scale and on a flat medium, of a selection of material or abstract features on, or in relation to, the surface of the earth or of a celestial body" (ICA [International Cartographic Association], 1973, p.7). This second definition makes it clear that the subclass differs from its generic class in some ways. But, the two definitions taken together do not identify the common properties shared by all maps, which set them apart from artefacts which are not maps. [Visvalingam 1989 p.26]
[b] The most important aspect of definition concerns visualization:
For the ICA, oblivious to the contradiction inherent in its own definition, the end 'product' or cartographic process (the map) is to be 'visual, digital, or tactile'. Yet how can numbers, the constituents of what has been called, appropriately enough, the 'invisible map' be described as a map before they have been processed into an image (the visual map)? In following the politics of expediency rather than linguistic logic, and anxious to ward off (in the words of one President of the ICA) the threat of 'rapid submergence' by the new GIS-based technology, the ICA has managed to shoot itself in the foot. It has given the non-map parity with the map! [Harley J.B. 1990 p.16]
[c] An old definition is surprisingly apt:
One of the definitions of the word "map" that appears in the Oxford Dictionary dates from a source of 1586, where it was used to describe "a circumstantial account of a state of things ("circumstantial" is defined as "full of circumstances, details or minutiae"): not a bad objective 400 years later! [Bickmore D.P. 1975 p.328]
3 The term and philosophy of visualization did not appear overnight:
The medium of graphics has long been used to create two-dimensional representation of spatial phenomena for the primary purpose of visualization and, for many, this has also been the essence of "cartography". [Muehrcke P. 1972 p.27]
4 It is the great wealth of pattern and variation that is of interest in many of the pictures drawn in this dissertation:
The dismissal of geographical diversity as merely 'noise' or 'residuals' is a betrayal of what geography is. [Taylor P.J. 1991 p.24]
5 [a] The cartographic basis of physical geography dates from a time when land was all important and people had few rights:
Traditional cartography is seen as an optimal response to a highly constrained technology based largely on pen and paper. Although many of the conventions of manual cartography appear to be intelligent choices, they have nevertheless been made in an extremely restricted environment which imposes a limited view of reality. Early digital technology did little to broaden the constraints, and led cartography, map analysis and spatial analysis in different directions. More recent hardware and the results of intensive research have produced a digital cartography which can successfully emulate its analogue parent. However, its true potential lies in less conventional methods of analysis and display and in the degree to which it can escape its traditional constraints. [Goodchild M.F. 1988 p.311]
[b] Putting the argument less gracefully:
In physical geography, only that which has an effect on mankind is studied. Now that men are much less dependent on the countryside than on cities, why have geographers not followed mankind? Why have geographers left their minds back on the farm? [Bunge W. 1975 p.177]
[c] New computer systems often fail practically as well as theoretically:
There seems to be an inverse law where, as the sophistication of GIS software grows, the attention to basic principles of graphic design lessens. The emphasis is on getting something on the screen quickly rather than getting something on the screen that is meaningful. [Medyckyj-Scott D. 1991 p.21]
6 [a] The geographical features most of us recognise are not physical — we do not live near mountains:
Base data is so traditional that it invites a critical review. Consider the use of rivers on base maps. With the invention of bridges to cross them and railroads to compete with transportation on them, it could be argued that rivers have become unimportant enough to be eliminated from the map. They might be replaced by major railroad lines. In general, the traditional base map data is especially unsatisfactory to human geographers. Terrain features might be profitably dropped in favor of a surface of population density. The "continents" of population clusters on the Eastern shores of the United States, Western Europe, China and elsewhere are many times more important to the economic geographer than the distinction between land and water traditionally shown and memorized. Major cities are more important "islands" for many purposes than the atolls of the Pacific. It is probably true that of all the degrees of latitude and longitude shown on the map, only the equator and the poles are on the mental map and, therefore, the other degrees might be dropped as superfluous. Much of what has become traditional base map material might have been selected for no better reason than the ease with which the material could be gathered by early explorers. It is much easier to plot the continental outlines, rivers and mountain peaks than to obtain a census of population or an accurate map of arable land. [Bunge W. 1966 pp.45-46]
[b] A more human-based geography is being called for:
The inspiration may come not only from the field of geography / cartography but also from different fields of artistic endeavour, and lead to the design of maps of human activities which are much more vital than the thematic maps of today. Paradoxically, developments in computer technology may lead to the creation of maps which, when it comes to spontaneity and liveliness, have more in common with the popularly-admired and beloved, hand-drawn maps of the middle-ages and the renaissance than with strict, formalized cartography of the modern day.
However, certain conditions must be fulfilled for this to happen. Suitable cartographic data must be made available, and computers must be adapted to user needs in such a way that the technology does not impose itself between the user and his future map. An additional precondition is a revived interest in working with spatial / geographical problems, and a renewal of the skills involved in solving such problems by graphic means as well as in presenting these solutions in a creative way.
If these requirements are fulfilled — and the geographer / cartographer must assume a great deal of responsibility for this — a new era will be initiated for human cartography. [Szegö J. 1987 p.231]
7 [a] There are many sources of digital information about people in Britain:
The only nation-wide count of the population in Britain occurs at census year; the last two censuses were held in 1971 and 1981. With no 1976 or 1986 mid-term censuses, this information is currently produced only once every ten years. However, during the inter-censal years there are a number of other sources which can provide information on the changing socioeconomic, demographic and manpower characteristics of the population at the local scale ... [McKee C. 1989 p.1]
[b] Pre-eminent in all these data sets is the decennial census:
Some information on other characteristics of the population such as house-hold structure, employment status, ethnic composition and housing situation can be gleaned from the annual General Household and Labour Force surveys, but the problem of small sample size virtually rules out their use at scales below the Standard Region. As a result, the Population Census is not just the best, but in practice the only, source of reliable data on a reasonably wide range of demographic and socio-economic characteristics at sub-regional scale. Moreover, it has the advantage of providing data down to the level of the individual enumeration district covering roughly 500 inhabitants, which, even if too small for certain purposes, can be treated as a building block for areas specially defined by the user (Rhind, 1983). [Champion A. G. 1989 p.113]
[c] National and local election results also provide information:
In many ways elections are a positivist's dream. Millions of people go through the process of voting in numerous countries every year and these decisions are put together and published by areal units ready for analysis by social scientists. [Taylor P.J. 1978 p.153]
[d] We use whatever information is accessible:
In this book, votes receive rather more emphasis than other activities only because they have become the currency of political sociology rather than because they are more "special" or necessarily more legitimate than other activities. [Agnew J.A. 1987 p.6]
8 [a] The fundamental cartographic questions are:
"What to map?" "How to map?" "What to do with the maps?"
These three questions sum up the main problems connected with the mapping of population phenomena and statistical data generally. Each question gives birth to a brood of lesser questions, the lesser questions to a third generation, and so on. The outlines of this genealogy will be traced in the present paper.
I. WHAT TO MAP?
The offspring of "What to map? are (1) "What has been mapped?" (2) "What can be mapped?" and (3) "What should be mapped?" ... [Wright J.K. (ed.) 1938 p.1]
[b] Yet fewer and fewer people are asking these crucial questions:
Eavesdropping in the conference bar, the cartographer's chatter is of the virtuoso Macintosh rather than the question of why and what we map. Are the mechanics of the new technology so preoccupying that cartographers have lost interest in the meaning of what they represent? And in its social consequences? And in the evidence that maps themselves can be said to embody a social structure? If material efficiency is allowed to dominate the design and construction of maps, we can see why the ethical issues tend to pass unnoticed. The technology of Geographic Information Systems (GIS) becomes the message, not just the new form or medium of our knowledge. [Harley J.B. 1990 p.7]
[c] Questions can often be more important than answers:
It is surprising to learn that such a seemingly perverse world view is embraced by modern physicists. In the words of John Wheeler, one of the grand old men of physics, "No elementary phenomenon is a phenomenon until it is an observed phenomenon." By this, Wheeler means that the rise of quantum mechanics has demolished the view that the universe sits "out there" while we sit back and observe it. The kinds of questions one asks — and the order one asks them in — has a profound influence on the answer one gets, and on the world view one builds up. [Rucker R. 1984 p.193]
[d] What are we doing this for?:
The analytic power to order data has potential equally for control or liberation. It is all a matter of questions asked and interpretations made. [Taylor P.J. 1991 p.30]
9 [a] Many eminent cartographers have called for a change of approach:
A second challenge requires a greater effort by cartographers to escape from the constraints of euclidean space and to exercise more imagination and originality in producing maps. Barbara Petchenik (Chapter 3) makes a plea that we "... move our consideration from the domain of rationality and analysis to an exploration of the domain of synthetic intuition". The map is a designed object and in our concern with the "scientific basis" of cartography in recent years we may have lost sight of the need for more imaginative design. Here cartographers may have to learn from graphic arts. An increasing number of thematic maps are being produced by graphic artists, not by cartographers.
Part of the reason for this is that cartographers are a fairly conservative group and are still largely prisoners of euclidean space. Kishimoto (1980) recently drew attention to this fact. We are increasingly coming to accept the essential difference between the thematic map and the topographic map but have not yet accepted that locational accuracy is not always a basic requirement of the thematic map. We can more effectively and imaginatively map other "spaces" and give more emphasis to map content than to geographic location.
Here again, cartographers should take note of the work of psychologists like Arnheim (1975) and Norman and Rumelhart (1975) who argue that what a cartographer would regard as a "distortion" of the "real" euclidean space may in fact lead to an increase in map clarity.[Taylor D.R.F. 1983 p.288]
[b] Computer cartography could aid, rather than set back, this new approach:
Cartography in the information age will centre about a multifaceted model of geographic reality, the spatial data base. The challenge facing cartographers will be to devise the theories, methods, and techniques needed to collect, load, manage, and transform the data items into useable information. The new cartographic process will form a continuum of information flow that can be described in terms of the various generic functions of a spatial data processor. Technological advances will provide the potential for collection of vast quantities of basic spatial data. The distillation of the data into descriptions of geographic reality that we can understand will require a conception of the abstract modelling process used by a human to comprehend spatial entities. Processes to manipulate the data must bridge the gap between a user's perception and a computer's representation of spatial reality. Automated cartography will expand from its robot draftsman roots to a spatial information system using artificial intelligence techniques to allow the cartographer not only to produce cartographic products but also to convey the user-designed view of geographic reality. [Guptill S.C. & Starr L.E. 1984 p.14]
[c] What ever we do, we must always keep the basic reason we draw maps in mind:
If the student already carries in his mind's eye the image of a base map showing the boundaries of the administrative units by which statistics are tabulated, he may derive from a table of statistics a hazy idea of the form of a distribution. If no such picture is present in his mind he can gain no such concept whatever without the aid of a map. How many of us could picture the distribution of population in our own state by studying the census tables alone? Hence statistical maps are tools for the discovery of new truth. [Wright J.K. (ed.) 1938 p.16]
|SASI Group, Department of Geography, University of Sheffield, Winter Street, Sheffield S10 2TN, UK.
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