How the odometer works in GpsGate
Odometer setup
An odometer is something that measures the total distance a vehicle has traveled. There are two types of odometers in GpsGate. Device odometer and server/virtual odometer.
Device Odometer
Many but not all GPS trackers have a built-in odometer. The main advantage of having an odometer is accuracy.
If your device supports odometer reading, you can activate it in the Device Mapper.
Server odometer
The server/virtual odometer is a GpsGate accumulator (in the image GPS distance).
GPS distance is the distance between every position update sent from the device to the server.
It will accumulate the distance traveled for a vehicle over time.
Enable the odometer to the vehicle
By default, the Odometer is not enabled when you create a user. To activate it, follow these steps:
1. Edit the user properties.
2. Under Accumulators, right-click on the vehicle and select Edit User. You can set a new odometer value at any time.
Reports and tracks
All reports and tracks will use the enabled odometer. If no odometer is enabled, GPS distance will be used.
Adjusting the odometer value
To edit the odometer, you need to edit the user and introduce a new value and the choice of a date:
When you do a change/modification to an Odometer for a specific date, then the odometer will create a correction for that date and adjust the current value.
Example 1
An example:
| Time | Odometer Value |
|---|---|
| T1 | 0 |
| T2 | 15 |
| T3 | 20 |
Making a correction at T2 and set the value to 10 will correct T3 and the value will be changed to 15 (T3 = Set value on T2 (10) + diff (5) = 15):
| Time | Previous Odometer Value | Correction | New Odometer Value |
|---|---|---|---|
| T1 | 0 | 0 | |
| T2 | 15 | -5 | 10 |
| T3 | 20 | -5 | 15 |
Example 2
Let's try with an example where the value of T3 was 15:
1. We do a correction of T3 and set it to 10
| Time | Previous Odometer Value | Correction | New Odometer Value |
|---|---|---|---|
| T1 | 0 | 0 | |
| T2 | 5 | 5 | |
| T3 | 15 | -5 (new correction) | 10 |
| T4 | 20 | -5 (from T3 correction) | 15 |
2. We later set the value of T2 > 10, so the status of the odometer at T4 will be as follows:
| Time | Previous Odometer Value | Correction | New Odometer Value | |
|---|---|---|---|---|
| T1 | 0 | 0 | 0 | |
| T2 | 5 | +5 | 10 | |
| T3 | 15 | -5 | 10 | The value doesn't change since we have set the value at T3 to be 10 |
| T4 | 20 | -5 (from T3 correction) | 15 | Change at T2 doesn't affect this, since at T3 we said it was 10 |
This means that if you do a correction anytime between T2 and T3, it will be reflected from that time until T3 (not until T4), where we have a set value. That way, the system can get historical values for accumulators at any given time in the past.
Effect upon changing the odometer in the device mapper
If you change the odometer, you need to reprocess reports and tracks for the change to effect on historical data. New data will always use the currently selected odometer.