I recently took a first aid course in order to have some sort of current certification, and our instructor mentioned that, if making a 911 call, it was preferable to use a land line, rather than a cell phone, since the operator would have your address automatically displayed on the screen.

We didn't discuss this in detail, so I am curious...Is this true throughout the
USA, common in the developed world, or just about everywhere? Cell phones do have a sort of GPS capability (pinging from towers in the system)...How easily accessible is this information to first responders? or do they have to contact NSA first (just kidding, mods!)?