Algorithm detecting exposure incorrectly when it was > 4 hours ago

[AdamLeonSmith]

Version

• Type of phone: Android
• OS Version: 10
• Model: Pixel 3a

Steps to reproduce

• Install the application build up location history
• Analyse your location data (I wrote this script to help) and find a point that has the greatest distance from your actual location (point A, at time T)
• Create a HA file that has point of concern just under 20m away from point A on both axes, let's call it point B
• Double check the distance using this script - I get output like this:

Point of concern identified... 16.68193716061866m & 19.721204492528148m & 0:00:00

• Add a test HA URL that reflects your current location showing point B at time T
• Load the URL in the app

Expected Behavior

The app should detect exposure based on the algorithm described here. I am assuming that the point needs to be within 20m on each axis.

Actual Behaviour

App shows no known exposure.

Please note I am happy to provide all the test files / location data to an individual developer, but not on github!

[AdamLeonSmith]

further testing has used pythagoras and confirmed the algorithm is accurate...