Specifically to calculate the trip that includes a detour.
This is an interesting question. I’ll follow-up with the FuelCheck APIs team and find out. I’ll provide an update when I know more.
I think I’ve misunderstood the way the app works. It seems if I set the detour to a high number like 10km then it just shows the stations within 10km. It doesn’t actually calculate the detour.
Still would be interesting to know if it uses https://api.nsw.gov.au/fuel-price-check/apis/post/fuelpricesapp/v1/fuel/prices/nearby and which reference points it uses; or if it uses another mechanism that handles distance to line segments.