>>On an Android device you can obtain:
>>
>>(a) From the magnetometer: The device orientation (i.e orientation relative to N).
>>(b) From the GPS : Bearing from current location to a specified other location.
>>
>>Both of the values are returned as the number of degrees E. of North.
>>So they are in the range of +0- +180 or -1 to -179 (-180 might be possible - haven't checked)
>>
>>I want to put an arrow on the screen pointing from the current location to the specified location (in the range of 0-360)
>>What is the most efficient algorithm ?
>>
>>Actually the magnetometer reading if for Magnetic N. and the bearing is True North but I can adjust for that later (same for the device window orientation)
>>
>>I can see a few implementations on the net but I've a feeling that they could be simplified..........
>>
>>Suggestions ?
>
>Christof Wollenhaupt had a session about sensors and how to use them within VFP at SouthWestFox last month. Send me an email if you want me to send you his material.

Christof will do the session on saturday on german devcon. Looks like it's in my track. Anyway I need more the gyro of an Android for now ...