title: Get ground altitude in a reliable way
body: <p>How should a  program determine that the Google Earth API has fetched an accurate altitude for a location?</p>
  
  <p>The Google Earth Plugin API has the following method to get ground altitude:</p>
  
  <pre><code>double GEGlobe.getGroundAltitude(double lat, double lon)
  </code></pre>
  
  <p>However, this function returns different results depending on the camera's distance from the targeted latitude, longitude. For example if the true altitude for a location is:  +181.60</p>
  
  <p>Calling the function when the camera is at different distances from the location returns the following altitudes:</p>
  
  <p>Return values of getGroundAltitude at different camera positions:</p>
  
  <p>-19.38   (camera is very far from location)</p>
  
  <p>+06.11   (camera is now closer)</p>
  
  <p>+89.13   (...)</p>
  
  <p>+166.82 </p>
  
  <p>+177.47</p>
  
  <p>+181.53  (camera is now v.close to the location)</p>
  
  <p>The returned value 181.53 is close enough to true altitude of 181.60</p>
  
  <p>The question is, how should the program determine that it has reliably got the most accurate altitude?</p>