title: Magnetic declination in JavaScript / Google Maps
body: <p>In the context of a Google Map JavaScript application, what is the best way to get the magnetic declination for a certain Lat/Lon?</p>
  
  <ol>
  <li><p>There seems to be no "easy" algorithm for that in JavaScript, or am I wrong?</p></li>
  <li><p>Is there a way with Google Maps API to determine this, I haven't found one...</p></li>
  <li><p>A Web Service which can be used. I have found <a href="http://www.ngdc.noaa.gov/geomagmodels/Declination.jsp" rel="nofollow noreferrer">WebSites</a> offering this, but no API.</p></li>
  <li><p>Also see <a href="http://www.geosats.com/webservice.html" rel="nofollow noreferrer">here</a>, there they use a JavaScript class for this (see comment)</p></li>
  </ol>