The power of maps as a means of persuasion derives from the presumption that they are true. This advertisement from Rand McNally demonstrates the point. "As a background for culture and a basis for business judgment, a set of Rand McNally Maps is of paramount importance . . . . and invariably accurate." Maps can be counted on to provide the "learning" one needs.
For another example of the presumption, from 300 years ago, see ID #1016, "Thus Men Go Safely” (1714). See also ID #2408, "Everything is on the map! You need only look." (1926).