I just discovered my iPhone "compass" app.

[WheelWalker]

It seems reasonable to assume the feature is not a magnetic compass. I'll have to investigate the magic of the device.

If it's not a magnetic compass, the iPhone does not correct for global magnetic declination. The iPhone displays true north.

If it's not a magnetic compass, any local magnetic attraction is irrelevant it the iPhone's directional display.

Am I understanding this device correctly?

[Ocelot II]

1. It shows magnetic north.

https://www.businessinsider.com/guides/tech/how-to-use-compass-on-iphone#:~:text=Once%20the%20compass%20has%20been,%3E%20%22Use%20True%20North.%22

[WheelWalker]

5. So it does. And subject to local attractions, as well.

Why in the world magnetic north is the default setting escapes me. I can't imagine when I would use a compass that I would want to know where magnetic north is if the device could tell me true north. My sole use of a compass would be over terrain with a map. But then, I don't get out much so there must be the need to know magnetic north more frequently than I can imagine.

Thanks for your help!

[Ocelot II]

12. That's how non-digital, "real" compasses work - they indicate magnetic north.

The app just simulates an ordinary magnetic compass, which was used in all kinds of navigation until the invention of GPS. The advantage of a regular mag compass is that it's self-contained, unlike GPS, which relies on satellite signals and an internal electrical source. So if you want to calculate a true course using a mag compass, you just have to consult a declination chart so you know what the variation between true north and magnetic north is at your location.

[ret5hd]

2. It also has an altimeter and your gps location...

handy functions in the right situations!

[Jerry2144]

3. It is magnetic

And there is a process to calibrate it through spinning it in a figure eight if it is thrown off by environmental things. Just move it in a figure right through the air, tracking a figure eight just like a child pushing a toy car on a race track would. Sound effects are optional

[WheelWalker]

6. So it is. I would never have imagined so. How bizarre.

Why, I ask, would one want to know magnetic north as a default when true north is available? I just can't imagine such compelling uses.

[Jerry2144]

8. It's easier to measure with a couple magnetic coils

True north would rely upon the gyroscopes and a gps calibration to figure orientation. It would take more power. And figuring the offer for magnetic version true takes more computing power since it had to find where you are on the ball of dust and adjust accordingly.

[WheelWalker]

9. Ah, I suspected something along those lines but don't know enough about anything

to hazard a fact-based guess. I appreciate your learned explanation.

[Jerry2144]

11. You're welcome

Not a software or computer engineer. But have used lots of navigational instruments during my time in Uncle Sam’s Yacht Club

[mitch96]

4. I checked the altimeter with a known source and it is a foot or so off..not bad..

Also if you go to the "measurement" app it also has an angle finder.. Great for finding stars..
The altimeter and angle finder is fun to play with on take off and landings on an aircraft.
m

[usonian]

7. I collect lots of apps. I look for the daily "gone free" and discounted apps.

📱So many apps that I recently discovered that the iPhone also makes phone calls. 📱

[WheelWalker]

10. It's almost unbelievable.