Mobile Geolocation and Atmospherics

Air density affects the path of the bullet, so you will want to know the temperature and pressure at your location. Humidity too, although that is less important.
Hardware location: You can get a Kestrel meter for about US$200, but some phones have a built in barometer or pressure sensor. Something to consider when you go phone shopping. You can get a digital weather station for about US$50 which will measure the temp/pressure/humidity directly, although some of these thing are meant for you porch rather than your pocket.








Web-based location:
You can get your location and altitude based on your location easily on the web, but accuracy may suffer, and you may not have Internet in the woods. The web may get your location wildly wrong. GPS is accurate, other methods of location may use silly things like your IP address and you really need to check.

Google Weather is a browser gadget which tells you the weather at your favourite locations, and there are moble phone apps which do the same. Your location must be accurate of course.

If all you have is your phone, you can still estimate your local atmospheric conditions if you have an Internet connection or a built in pressure gauge.

See also: Two kinds of pressure