from Apple's Documentation :

```
@property(readonly, nonatomic) CMMagneticField magneticField

```

*Returns the magnetic field measured by the magnetometer. (read-only)*

*The value of this property is the total magnetic field observed by the device which is equal to the Earth’s geomagnetic field plus bias introduced from the device itself and its surroundings.*

```
@property(readonly, nonatomic) CMCalibratedMagneticField magneticField

```

*The CMCalibratedMagneticField returned by this property gives you the total magnetic field in the device’s vicinity without device bias. Unlike the magneticField property of the CMMagnetometer class, these values reflect the earth’s magnetic field plus surrounding fields, minus device bias.*

Which of the two do I need to use if I want to get the device's deviation from the North in degrees? That is,the value a digital compass on the iPhone would display, based on where the device is facing (e.g. 90, 180, 193, etc..)

I know that none of the above return degrees in integer format. The documentation is not clear as to what exactly they return.. I think it's MicroTeslas..

But if they *do* return a MicroTesla value how do I convert this value into an integer representing degrees? Do I have to multiply that MicroTesla value with some constant or something of that nature?

Thanks for any help!