Google Maps - Compass disappointing in car

Discussion in 'iPhone' started by bobbba, Jun 19, 2009.

  1. bobbba macrumors regular

    Jul 7, 2008
    Just travelled back with my new 3gs. The compass worked great on foot with google maps but it was really poor in the car. It struggled to show the right direction and it made the tracking (with diretion) poor by causing pauses as it tried to update(on the 3g, the tracking seemed pretty good).

    Just hope that they improve it with updates or that Tom Tom will be ok when it's released...
  2. Que macrumors 6502

    Apr 5, 2009
    i'd suggest that the tomtom app will solve any problems you have with maps.

    having used maps in the car a few times, it's acceptable at best so a compass wouldn't be expected to fix that. it just means it's crap but at least it knows which direction on the compass it's being crap towards.
  3. javaGuru macrumors 6502a


    Jul 15, 2007
    Did you calibrate the compass? I believe it has to be calibrated first. There should be direction on how to do this.
  4. avaloncourt macrumors 65816

    Oct 18, 2007
    You're probably experiencing what is known as 'magnetic deviation.' This is when the metal of the surrounding structure (your car) creates inconsistent readings as you turn in various directions because the structure is altering the magnetic fields around you. There is more to affect it in some directions than others due to things like the engine ahead of you versus just the doors on the sides. This is why when you are standing in the open you don't experience the same issues.

    Edited to add: JavaGuru is correct. There may be a calibration procedure just as there is for car compasses. Vehicle compasses require that you drive in tight circles many times so that it can develop a correction.
  5. t0mat0 macrumors 603


    Aug 29, 2006
    Google Maps itself works great in a car having tested it a lot. The magnetometer might be getting interference, and it might need calibration.

    TomTom will be fine. It's pretty easy to see which way you're moving on Google Maps with GPS tracking on and zoomed in a bit.
  6. smr macrumors 6502a

    Sep 14, 2007
    Shropshire, UK
    I have just driven to work, and the compass worked OK. The map was generally (within 10 degrees) aligned with the road, and the GPS tracked my position pretty well.

    Do you have one of those heated front screens? The element in the glass can attenuate GPS, and possibly magentic fields as well?
  7. PNutts macrumors 601


    Jul 24, 2008
    Pacific Northwest, US
    As the other posters mentioned a recalibration in the car might do the trick. Historically, magnetic compasses have been problematic in cars.

    Calibration information from Apple's support site:
  8. jmpage2 macrumors 68040


    Sep 14, 2007
    I have tried to use the compass feature in three different vehicles:

    1. Jeep Compass (HAHA!)
    2. Acura MDX
    3. Audi A4

    It doesn't work in any of them. Constantly getting interference. Extremely annoying and really limits the pluses of the compass in the vehicle, which would have been handy for us several times when we were trying to navigate to nearby restaurants.

    All in all the compass seems like more of a gimmick or something useful for pedestrians.

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