>> * Barometric sensors >You mean like current air pressure? Are there common devices out there with these? (None of my computing devices have anything like thi

>> * Barometric sensors >You mean like current air pressure? Are there common devices out there with these? (None of my computing devices have anything like this, for example.) (and what would I want this for?) Most modern phones have a barometric (yes, air pressure) sensor included. Having semi-accurate altitude data helps the GPS receiver obtain a faster location fix, but it can be used for other things as well.