title: Creating a compass on a non-directionally aware device
body: <p>I need to develop a compass for a device we are using. This device is directionally unaware (no gyroscope), but has a GPS module. How can I make a compass, with a needle, that leads from a start coordinate (likely their current position) to an end coordinate?</p>
  
  <p>My current thoughts are:</p>
  
  <ol>
  <li>Poll coordinates on the GPS sensor as quickly as appropriate.</li>
  <li>Record coordinates where the PDOP is within a respectable range (maybe less than 2.0).</li>
  <li>Determine the direction they are facing based on the coordinate changes of them walking.</li>
  </ol>
  
  <p>I have a few issues with this though:</p>
  
  <ol>
  <li>Firstly, the unit has to be moved around to get a sense of where they are.</li>
  <li>Doesn't seem like it would be the most accurate, i.e. how many past points do you use to determine direction change?</li>
  <li>I'm not really sure if this is a feasible solution. Is there some implementation theory I can read on this?</li>
  </ol>
  
  <p>Is there a better way to solve my problem? The scope of the project involves going from a 'current location' to some geo-tagged item in an oil field.</p>
  
  <p>Using a Windows Mobile 6.5 device - C# on VS2008.</p>