On today’s edition of Weekend America, professor and writer Mark Monmonier is interviewed about mapping errors, beginning with GPS navigation errors — blame the maps, not the GPS signals — and moving on to what, the interviewer asks, the three biggest errors in mapmaking have been.

Previously: Mark Monmonier; Review: How to Lie with Maps; Mark Monmonier Does NPR; Review: From Squaw Tit to Whorehouse Meadow.