In the context of a Google Map JavaScript application, what is the best way to get the magnetic declination for a certain Lat/Lon?
There seems to be no "easy" algorithm for that in JavaScript, or am I wrong?
Is there a way with Google Maps API to determine this, I haven't found one...
A Web Service which can be used. I have found WebSites offering this, but no API.
Also see here, there they use a JavaScript class for this (see comment)
They have shard this. For Google maps mashup with source see:-