MAP TYPOLOGIES: 20TH CENTURY USAGE REVISITED

摘要

The ways in which maps were categorized evolved in interesting ways in the 20th century. A major typology was the reference/thematic dichotomy. The term thematic map came into use in mid-century, although the distinction between reference maps and the maps eventually labeled thematic had been made decades earlier. The question of whether it was the maps, their manner of use, or the mental processes employed was a matter of some discussion. Within these two divisions, subcategories had labels. Thematic were divided into subcategories such as choropleth, dasymetric, isarithmic, and dot maps, categories that were conceived of in varying ways. Some were relabeled, not always with terms that were lasting. Distinctions blurred between others. By the end of the century, geographic information systems that took a procedural approach to constructing maps were devoid of some of the traditional category labels, though the literature of the maps themselves was not. There was also criticism of terms like reference and thematic as meaningless labels, with maps conceived of as social constructs creating reality rather than representing it. Some typologies have probably outlived their usefulness. Others are developing and are likely to be useful temporarily as well. (This paper is inspired by, and is an expansion of, a short piece on map typologies written for the 20th Century Volume of History of Cartography, founding editors David Woodward and Brian Harley.) Typologies consist of categories of phenomena that share common characteristics. Map typologies are based on various criteria including content, data measurement, physical or conceptual form of the distributions mapped, and the form of the symbols on the map. Ideal typologies include all instances of a phenomenon (they are exhaustive) and categories that are mutually exclusive (no individual example belongs in more than one category). Maps, however, are notoriously difficult to categorize and we find some maps straddling categories in a typology or fitting no category. Yet, typologies have facilitated communication about maps and it is difficult to imagine teaching a class, conversing with a fellow cartographer or map reader, or writing about maps without using terms for categories of them. On the other hand, typologies also channel thinking, and looking their definitions and the uses of typology vocabulary can potentially clarify our intellectual history and perhaps even facilitate clearer thinking in the present or future. Cartographers in the 20th century most commonly dichotomized maps into "reference" and "thematic." Reference maps, often called "general reference," include, most universally, such maps as topographic, place-name wall maps, and general atlas maps. Their description may include terms and phrases such as multi-purpose, showing a variety of phenomena, and showing locations of specific features. Thematic maps are exemplified by population, resource, and crop maps and have been described with phrases such as special-purpose, showing a distribution, or showing form. The term "thematic" was not coined until the 1950s (Creutzburg 1953, Fabrikant 2003), even though they had undergone considerable development in the 19th and early 20th century and had roots well before that (Robinson 1982). Descriptions of both categories presented problems, given that some distributional information is present to some degree in all maps and likewise with locational information. The user of an atlas map may see patterns of mountains or of major cities; the user of a population map may be observing which political units border one another. Interestingly enough, the nature of the difference between the two categories, and the problem of what information is obtained from which maps, was a thread in the Nature of Maps (Robinson and Petchenik 1976), and the authors argue that the differences are cognitive rather than inherent in the maps themselves. A further problem is that some maps defy classif