Distance Calculations
Distance is calculated using coordinates on the server. It's in meters in the database. If it's incorrect, it means that something is wrong with the data. One possibility is that data is not reporting in correct order.
Would this be caused by the vehicle being out of GPRS signal, and the tracker unit reporting buffered GPS fixes newest first when it gets back into GPRS range?
Yes, it can be.
Shall I raise a Github issue for this?
You can, but that's how it's designed to work at the moment.
I have Teltonika FM1100 tracker units in our vehicles and am trying to compare distance values as reported by the Teltonika units and those given by Traccar.
For example, Traccar report gives distance as 133.43km, Teltonika gives 225.5km - and to add to confusion if I sum the "distance" values stored in attributes I get 4575.4km (presuming it to be metres)!
What is stored in the "distance" element of attribute and how does Traccar convert it, and why should it differ so much from the Teltonika value (which is correct).