title: Converting from longitude\latitude to Cartesian coordinates
body: <p>I have some earth-centered coordinate points given as latitude and longitude (<a href="http://en.wikipedia.org/wiki/World_Geodetic_System" rel="noreferrer">WGS-84</a>).</p>
  
  <p>How can i convert them to Cartesian coordinates (x,y,z) with the origin at the center of the earth?</p>