I don’t hear this so much from cartographers and GIS professionals as I do from nearly everybody else who has to read our maps, “I didn’t even read the text on the map’. Matt Baker’s recent post addresses one of the most common causes, overly wide paragraphs, and I’ll cover another here, which is the size of text.

A paragraph of text on a map has a tendency to look like a block of graphical noise if the type size is too small. Think about how many poster-sized maps you’ve seen with blocks of text using 11 or 12 point type. I certainly made that mistake a number of times, and I specifically remember thinking, “I can fit it all on the map if I reduce the font size to 10.5.” The problem is that this text is too small to read and there is too much of it to read while you are standing there with two or three people waiting behind you. Text blocks on poster-size map pages need to be extremely concise and legible.

There are (at least) two things you should ask yourself, as a mapmaker, before you put text blocks on your map:

  1. Does somebody need to read this text to understand the map? If so, make the text large enough to be immediately recognized as ESSENTIAL READING. If not, consider eliminating the text.
  2. Is the gist of this text to explain, qualify, elaborate, or to meet publication or submission guidelines? If so, you probably do need to include the text but remember that guidelines are only guidelines. Make anything really important large enough to read. Information of secondary importance can be eliminated from the page by way of reference to another source with that info – for example, a publication or Web site. Publishing your maps on the Web is liberating for this sort of stuff—all you need is a “More Info” hyperlink to the information that anybody who is passionate about your topic will be looking for anyway.

A third question you might need to ask relates to required text blocks on your map page.

Does the text allow your publication to meet legal obligations? Disclaimers, required source citations or credits, agency or publication details, or contact information are required for some maps. For these text blocks, make the text smaller; we all know the purpose of “fine print”, and when we need it we know where to look.

Last, a few design guidelines:

  • Large blocks of text should be in serif font (like Times New Roman) as the serifs make the text in the blocks easier to read. You can use sans serif fonts for small text blocks, titles and subtitles, and other small strings of text.
  • Full justification is harder to read – while it might make your text blocks look nice and rectilinear, it is actually easier on the eye to have the same amount of spacing between each word in a line of text. In addition, the irregular shape of the right edge of the text block is less structured and allows the eye more freedom of movement. (A text block is like a box, and it boxes the eye in.)
  • Uppercase lettering is more visually prominent but harder to read, so avoid using it, even for titles.