The best way to keep up to date is feedback from our community of users. Users can report when one-way streets change direction, or edit street names that no longer match those on road signs. Many people do just that, insisting that the facts be straightened out, even though there is no economic incentive in it for them.
Companies now appear to be looking at popularizing "geo-tagging", which means going beyond the altruism of the few and appealing to the baser urges of millions whose main "point of interest" is themselves.
Non-commercial OpenStreetMap is perhaps the most ambitious "geo-tagging" scheme of all : it aims to map highways, streets and footpaths over the whole globe and give away the maps on the Internet to anyone who wants them.
It is closely related to Wikipedia, the online encyclopedia which survives on a little money and a lot of community spirit, but instead of trying to record all human knowledge, is dedicated to recording and describing the world's land surface.
Contributors to OpenStreetMap take handheld GPS (Global Positioning System) devices with them on journeys, or go out specially to record GPS tracks. They record street names, and other landmarks using notebook, digital cameras and voice-recorders and enter these on the website by hand.
Marco Polo, Christopher Columbus and captain James Cook would be amazed at how easy it is for untrained people like you and me to help chart the globe in the 21st century.
Welcome Globe-trotters with modern explorers gadgets. Keep your own body compass healthy and never lose your wealth bearing. Bon-voyage . . .