Typography, as an aspect of cartographic design, is the craft of designing and placing text on a map in support of the map symbols, together representing geographic features and their properties. It is also often called map labeling or lettering, but typography is more in line with the general usage of typography. Throughout the history of maps to the present, their labeling has been dependent on the general techniques and technologies of typography.
History
For most of the history of Cartography, the text on maps was hand drawn, and Calligraphy was an essential part of the skill set of the cartographer. This did not change with the advent of printing in the 15th Century, because the dispersed placement of the text did not lend itself to the use of Movable type. Instead, printed maps, including text, were drawn, engraved, and printed using the Intaglio or "copperplate" process. It was typical for the cartographer to not label the map himself, but to leave it to the master engraver. Text styles frequently changed with the tastes of the time, but were often very ornate, especially in non-map elements such as the title.
The development of Photoengraving, Zincography, and wax engraving in the mid-19th Century significantly changed the production of maps and their labels, enabling the addition of printed type to maps using stamps, but map lettering still required a great deal of skill; this remained the state of the art until the development of Photolithography in the 1950s. The photographic platemaking process meant that type could be produced on paper in a variety of ways, producing map labels of the same quality as book text. That said, as late as 1960, Arthur H. Robinson still advised new cartographers to be skilled in freehand lettering, and mechanical lettering tools were still in common usage through the 1980s, encouraging a very simplistic functional style over any aesthetic character.
A significant turning point was "Die Anordnung der Namen in der Karte", a 1962 essay (re-published in English in 1975) by Swiss cartographer Eduard Imhof, considered the greatest European cartographer of his day. Imhof analyzed the best maps he could find, such as the Swisstopo topographic maps, deriving a set of general principles and guidelines for type design and placement, which subsequent research has largely corroborated and further developed, and which forms the core canon on the topic found in modern cartography textbooks. In 1972, Pinhas Yoeli began to codify Imhof's guidelines mathematically, setting the stage for Automatic label placement. In 2000, Clifford Wood extended Imhof's guidelines, based on the intervening 25 years of research and practice.
The rise of Desktop publishing around 1990, including graphics software, laser printers, and inkjet printers, combined with the improving design capabilities of Geographic information systems, greatly increased and facilitated the more thoughtful design and use of type on maps. A wealth of typefaces became available, and it became easy to place text anywhere on the map. This completed the shift of skill in map typography from construction to design.
Purposes and goals of map labels
Text simultaneously serves several purposes on maps. In 1993, D. J. Fairbairn introduced a taxonomy of the purposes of text on maps, identifying fourteen types of text role. Since then, others, such as cartography textbooks, have described the variety of roles of text, with the following generally being the most common:
Identifying unique features, such as "The United Kingdom" Categorizing features into groups, such as "Smith Park" Describing or explaining information that cannot be directly derived from the map symbols or corroborating the symbolized information, such as "Box Lake (dry)," a note on the history of a building, or varying the size of city labels according to population to the size of the city symbols. Locating features that are not shown by a distinct symbol, such as "Arabian Sea" or "Rocky Mountains." Prescribing or Proscribing action, such as "No Camping." Organizing the conceptual structure of the map as a whole, such as strengthening the visual hierarchy. Beautifying the map as a whole. Characterizing the map with a particular aesthetic feel, such as using a typeface that looks playful, modern, or historical.
Aims and goals of cartographic typography In 1929, Ordnance Survey cartographer Captain John G. Withycombe, in a critique of the state of map lettering, listed five essential aims of cartographic typography. Legibility: readers must be able to read the text, especially, as Withycombe states, "when superimposed upon the detail of a map." Reproducibility: this may not be as problematic as in 1929, but even modern technologies (especially computer screens) can have difficulty with the relatively small sizes of map labels, especially in colors other than solid black. Style: Withycombe points out that careful choice of "alphabet" (typeface) contributes not only to aesthetic appeal, but also to the two aims above. Contrast: labels for different kinds of features should themselves look different. Harmony: the various typefaces and styles used should work and look good together, and should produce an overall look of order and professionalism.
In his 1962 paper, Imhof reiterated the primary importance of legibility, and added the following requirements (listed here with modern terminology); he then showed how most specific guidelines and practices are derived from these principles: Association: the reader must be able to clearly connect each label to the feature it is labeling. Withycombe's contrast is an important part of this. Conflict avoidance: many of the above aims can be aided by placing labels so they do not overlap too many map features, especially other labels. Extent: labels should help to indicate the spatial extent of the features they label, as well as their distinction from other features Hierarchy: like the symbols for each feature, Withycombe's contrast in lettering can be used to strengthen the Visual hierarchy of features in the map. Distribution: "Names should not be evenly dispersed over the map, nor should names be densely clustered."
In subsequent literature, textbooks, and the GIS&T Body of Knowledge, legibility, association, and hierarchy are typically listed as the most crucial of these aims, while conflict avoidance is one of the core foundations of Automatic label placement.Guidero, E. (2017). Typography. The Geographic Information Science & Technology Body of Knowledge (3rd Quarter 2017 Edition), John P. Wilson (ed.). DOI: 10.22224/gistbok/2017.3.2
Type styling
Many of the aspects of type styling can be chosen and controlled by the cartographer when designing a particular label to serve the above purposes. In this sense, they are akin to the visual variables of map symbology; in fact, Jacques Bertin extended his own visual variable system to including type styling in 1980 (in French). This work has largely been ignored in English-speaking countries, although similar ideas have been developed by others. The most commonly cited and used typographic variables include:
Form is akin to shape in the original visual variables, and serves much the same purpose, to differentiate nominal variables, most often to distinguish different classes of features (city vs. river vs. mountain vs. country). In addition to the following, Bertin also includes other shape variations, such as width (condensed, compressed, extended, etc.) and texture or patterned fills, which are used less often in maps due to their effect on legibility. Typeface ("type shape variation" in Bertin 1980), in addition to its common use to differentiate feature type, has a major influence on the aesthetics of the map. Posture (which Bertin likens to orientation), whether roman, italic, or oblique, is typically used like typeface to differentiate feature types. Wood mentions the common use of italics for labeling hydrographic features, due to its curving form that suggests water flow. Case ("sign shape variation" in Bertin 1980) has a more ordinal sense than typeface or posture, and many cartographers use ALL CAPS to indicate larger features or special types such as national capitals. Its role in visual hierarchy is debatable: at times, upper case seems to stand out because the characters are larger, but at other times it seems to recede because the characters are less interesting than Title Case. Orientation, the direction the characters are aligned, is used much more commonly with type than with map symbols. The most common reason to have text not be horizontal is to follow linear features, and sometimes elongated area features (which Imhof calls "ribbon-like"). Size (usually measured by the block height in points) is usually used for a piece of text in a similar fashion as the map symbol it is labeling: to indicate the geographic extent of the feature, to fit into the visual hierarchy, or to represent some quantitative variable. Spacing between characters (tracking), words, and lines (leading) is often varied on maps for a variety of purposes. For example, Imhof suggests using character spacing to spread an area label over the entire area feature, but counsels against doing the same for line labels. Weight, whether bold, black, light, or something in between, was considered by Bertin as a value-like variable, suggesting that it has an ordinal representation and a strong influence on visual hierarchy. Hue, one of Bertin's original visual variables, is rarely used in type to carry information on its own, although there are exceptions, such as using red (with its connotation of danger) for warnings. Instead, hue is usually used to match the text to the hue of the symbol it is labeling, strengthening its association. Value, also one the core visual variables, is typically used to match the value of associated symbols, although often darker, because lighter text can be less legible and have reproducibility problems, especially when printed. It is also commonly used for emphasis in the visual hierarchy. Decoration, additional symbols attached to the text, is used differently on maps than in block text. Common decorations such as underline and strikeout are rarely used, but a halo or mask, hiding the underlying features around a label, is often used to increase legibility where there are many features that cannot be avoided.Peterson, Gretchen N. GIS Cartography: A Guide to Effective Map Design (2nd ed.). Boca Raton, FL: CRC Press (2015). 89-90. A callout box or leader line are forms of decoration that are added to aid feature association when a label cannot be placed adjacent to the feature. Another form of decoration are highway shields, symbols attached to route numbers, usually to make them look like the signs seen along the highway.
Placement Determining the ideal location for each label that needs to be on the map is a complex process, with hundreds or thousands of labels competing for space, in addition to the map symbols which are usually more important. It is not a purely subjective decision process; for each label, some locations meet the aims above (especially legibility and association) better than others. An understanding of what makes some placement better than others thus streamlines the process of creating an effective map.