One of the most useful approaches to the study of cartography is to view maps as a form of visual communication--a special-purpose language for describing spatial relationships. Although it is perhaps unwise to draw a direct analogy between cartography and language, concepts such as "grammar" and "syntax" help to explain, at least metaphorically, the sorts of decisions cartographers make as they compose maps. Cartographers seek to make use of visual resources such as color, shape and pattern to communicate information about spatial relationships. The analogy with language also helps explain why training in principles of effective cartography is so important--it allows us to communicate more effectively. Without a knowledge of some of these basic principles, the beginning cartographer is likely to be misunderstood or cause confusion.