In order to better organize/manage the trips in a logbook, a user can add checkpoints from time to time. A user can capture important events and locations too for e.g. fuel fill up or servicing by adding checkpoints.
A checkpoint ascertains that the Odo value in fact equals the value the user wants to record at any point in time. In a way it groups and finalizes the trips precisely. A recalculation occurs i.e the app verifies that all the trips made up to this point in time, or the distances covered in km - in fact matches this value.
One can click on the last Logbook Odo in order to either confirm it as a checkpoint as shown in the figure below:
Or, can click on it in order to edit the value. as shown in the figure below:
On clicking save, a recalculation screen appears as shown below.
Any value that falls short or exceeds during this calculation (current checkpoint value - (old checkpoint value+distance traveled in each of the trips after that) ), is then shown as an error message (in this case, 22.4 km difference marked in red) which must be resolved either by adding/removing trips manually, so the gap is filled.
Checkpoints can be deleted - if the user does not wish to have any of these checks/verifications at a given point in time.