I'm building a dense network of atmosphere sensors using smartphones in order to build a more accurate weather model [1]. Android's APIs allow us to access the raw data, but all of Apple's marketing talks just about "elevation". I'm hoping they give us access to the raw sensor, and not just elevation change.

Humanity ought to have a much better weather forecast than we have now, as we're nearing 1B+ internet-connected barometers. Hopefully Apple's sensors can add to this network!

[1]: http://pressurenet.io

I'm in a very small niche of users, but I'm a skydiver and have an app on my GS3 which tracks freefall speed:

https://play.google.com/store/apps/details?id=com.platypii.b...

Having a barometer was a key feature I looked for in a phone.

I build an avalanche safety app http://www.ullrlabs.com and knowing your elevation is one key aspect of determining the avalanche risk (due to differences in altitude for wind effect, temp, and snow accumulation).

It can be used as a basic altimeter. Which can help pinpoint your location better, they're meant to be accurate to within 10 feet vertically from a base point.

Weather predictions based not on widely spaced weather stations, but millions of individual GPS-capable mobile ones?

It makes GPS locking much quicker by optimising some calculations.

Many people's migraines are correlated to changes in barometric pressure. What's really cool is with thousand (or millions!) of people tracking when they have a migraine while using a barametric pressure tracking device, we'll finally get solid data to see how strong this correlation is and whether it involves other factors.

Medical science can't, for obvious reasons, do a lot of controlled experiments with people. The next best thing is using "big data" collection over millions of people over many dimensions. Knowledge will benefit immeasurable.

It's an interesting environmental variable to track, especially if you get migraines or have mood swings. If it turns out increased pressure is correlated to your headaches, you can take extra precautions to avoid other triggers.

Determine the location within tall buildings more accurately but obviously not 100% accurate. This is one step closer to pinpointing the exact location of the phone within tall buildings.

Dedicated backcountry and backpacking apps can now use the barometer to determine elevation rather than having to use GPS approximation.

I'd be interested in this for tuning carburetor jets. I'm sure there are lots of air-density related uses.

Quicker GPS locks.

Same question here.