Magnetometer how to use it?

[Tiger54]

The compass has a bad resolution (only 1.0 degree step).
So I was thinking: "why not use the magnetometer?"

With the Magnetometer, I want to measure an angle between 2 points (I don't need the cardinal north, it is realtive).

This is my code to get the values from sensors:

class MagnetometerFilter : public QMagnetometerFilter
{
public:
    MagnetometerFilter()
    {
    }
    bool filter(QMagnetometerReading *reading)
    {
        x = reading->x() * 10000.0;
        y = reading->y() * 10000.0;
        z = reading->z() * 10000.0;
        precision = reading->calibrationLevel();
        return true;
    }
    qreal x;
    qreal y;
    qreal z;
    qreal precision;
};

To measure the flux in Tesla, I get a value from 0 to 1 (this is from the help).

But I don't understand something:
- I need to multiplicate the value with 10'000 to see a good value! Don't know why.

And my question is:
- How can I convert the tesla value to degree? If it is possible?