Question

I’m trying to measure the distance between two points (longitude, latitude). My problem is that I get different results on iOS then on Android.

I’ve checked it with this site and the result was that the Android values are correct.

I’m using this MapKit method to get the distance in iOS: distanceFromLocation:

Here are my test locations:

P1: 48.643798, 9.453735
P2: 49.495150, 9.782150

Distance iOS: 97717 m
Distance Android: 97673 m

How is this possible and how can I fix this?

Answer 1

So I was having a different issue and stumbled upon the answer to both of our questions:

On iOS you can do the following:

 meters1 = [P1 distanceFromLocation:P2]
 // meters1 is 97,717

 meters2 = [P2 distanceFromLocation:P1]
 // meters2 is 97,630

I’ve searched and searched but haven’t been able to find a reason for the difference. Since they are the exact same points, it should show the same distance no matter which way you are traveling. I submitted it to Apple as a bug and they closed it as a duplicate but have still not fixed it. I would suggest to anyone who wants this to be fixed to also submit it as a bug.

In the meantime, the average of the two is actually the correct value:

 meters = (meters1 + meters2)/2
 // meters (the average of the first two) is 97,673

Apparently Android does not have this problem.