GPS technology is a great tool and is highly accurate in most cases.  Still, one should not rely completely on this service will real maps or facilities as noted in the artile.

QUOTE: But GPS only tells you where you are in latitude and longitude — building the visual maps that need to be placed under those pinpoints is a challenging multi-billion-dollar endeavor. Even Google — which stood on the shoulders of mapmakers such as TomTom-owned Tele Atlas and Nokia-owned Navteq when building its remarkable geographical database — can get it wrong every so often.