Do any one have idea for finding true direction using iPhone? I want to implement such application in which I need to find direction in which iPhone is pointing and want to make application same as compass application in iphone 3GS.
Does iPhone 3G supports compass functionality? And can any one tell me how compass application find directions so accurately like a real magnetic compass?
Please help me for this. I am in a critical situation.
Thanks in advance.
here is a sample code link from apple.com for using magnetometer and Core Location https://developer.apple.com/library/ios/#samplecode/Teslameter/Introduction/Intro.html
you need to be logged in, in case you cant find the page, just look for Teslameter example in Sample Code section of https://developer.apple.com
Here i have given you the simple PDF to get an overview about the Magnetometer, CLLocation and accelerometer functions. make a look about this.,
http://learningiphoneprogramming.com/pdf/The_Sensors_in_your_iPhone.pdf
You can get lot of help from this link http://answers.oreilly.com/topic/1657-how-to-use-the-iphones-digital-compass/
also if you want to search it in Apple look for CLLLocationManager and UIAcelerometer.
You will find the code hopefully.
Taimur.
The iPhone 3GS has a magnetometer for detecting magnetic position, the 3G doesn't so you won't be able to do it on a 3G
来源：https://stackoverflow.com/questions/3675643/finding-direction-in-iphone-like-in-compass