13

Does anybody know how to convert results from the magnetic-field sensor from an android device to coordinates using the World Magnetic Model? Is there a webservice that does that?

blahdiblah
  • 33,069
  • 21
  • 98
  • 152
Buda Gavril
  • 21,409
  • 40
  • 127
  • 196
  • 3
    Think about it: why would they go through the trouble of getting satellites to orbit if it was that easy? – mensi Apr 24 '12 at 11:36

2 Answers2

22

You cannot do this. First of all you want co-ordinates which means 2 values. Only one what magnetic field provides is not enough. Second - even if you catch it correctly you will only know that you are on one of those isolines. That's not too much. You can be in Europe or Africa as well. Third and final - it's real magnetic field around you. Nearby passing car which is heavy metallic object object will change your field dramatically. Other magnetic sources like your phone ringing or electric wiring around will tell you that you travel from Brasil to Egypt when you come form Bathroom to Living room.

Alex
  • 4,457
  • 2
  • 20
  • 59
  • As said, you cant work it that way round, you can use the WMM the orther way round to get the magnetic field based on your lat and long and time - http://developer.android.com/reference/android/hardware/GeomagneticField.html – Symeon Breen Apr 24 '12 at 10:34
2

Actually, the finnish company IndoorAtlas claims it can do at least indoor navigation based on the geo-magnetic field.

There's also a WhitePaper about the technology used.

But as said, it's only for indoor-navigation, so not a replacement for GPS.

Ridcully
  • 23,362
  • 7
  • 71
  • 86