Just a little more info for those that are interested.
In general, it is extremely frustrating having to recreate a solution to a
problem which has clearly been solved already many times. I can list several
iOS apps which I use personally that appear to give reasonably accurate
measures of
Hi Graham,
PS The only test data I have been able to find for the XCode Simulator is a
bike ride in California which runs along giving a succession of GPS . It is
quite useful, but naturally it doesn’t involve anomalies.
You can make your own location simulations to run in the iOS simulator.
Thanks Alan and Bob - I was beginning to think I was alone on this one…
Yes, I do look at horizontal accuracy. I found out the following using my
iPhone XS.
1. Horizontal accuracy tends to be rather poor for the first 10 to 20 readings
after activation, typically 65 metres. In context, a test
Seems to me if you are tracking linear movement, you need to average the
trending values, say the last 5 or 10 reads, against a time base, and reject
the ones outside an acceptable tolerance. You may reject some good data here
and there, but something grossly outside tolerance should be pretty
Hi Graham
Are you checking the horizontal accuracy of each reading? (It's part of the
array of data with your lat-longs, as well as speed, etc - though not on every
phone).
If not, try that and see if the anomalous readings are hugely out. From my
experience, that's normally the case. If so,
