title: Getting iPhone geodata
body: <p>I am developing an augmented reality app and I need to use the iPhone sensors to obtain the following information/data:</p>
  
  <ul>
  <li>geographic latitude, longitude and altitude (to provide location relative to earth’s surface and mean sea level)</li>
  <li>phone viewpoint central heading (0°=N, 90°=E, 180°=S, 270°=W)</li>
  <li>phone viewpoint central elevation (0°=horizontal, -90°=vertical downwards, +90°=vertical upwards)</li>
  <li>phone tilt (0°=portrait/upright, 90°=landscape/top points left, 180°=landscape/top points down, 270°=portrait/top points down)</li>
  <li>phone angle subtended vertically (ie. along nominal top to bottom)</li>
  <li>phone angle subtended horizontally (ie. along nominal side to side)</li>
  </ul>
  
  <p>I already know hot to find latitude, longitude and altitude, I was wondering what kind of API or library I could use to find the other data, like the phone angle and the phone viewpoint etc. What API would I use? Some sample code? Links? Discussion? Im just trying to figure out how to find this data!</p>