All maps leave things out. They have to, not merely to fit the information they want to give into a format many thousand of times smaller than the actual stretch of land or sea, but also in order to present it with some selective coherence. Road maps are for people sitting behind steering wheels and greatly exaggerate the width of the roads while often omitting railway lines altogether. Tourist maps of towns represent ancient monuments and shops as unnaturally large while ignoring side streets. The mental maps of taxi drivers in India appear to consist entirely of landmark buildings and tea stalls. If cats had maps they would show a house as a series of desirable warm spots, soft surfaces, hiding places and escape routes.