Proving You Turned Up
The commercial case that justifies most field deployments, and the narrow data it actually requires.
Disputes about whether a visit happened are real money in field service, and they are the most defensible reason to collect location data.
The problem it solves
A customer says nobody came.
An invoice is queried because the time on site looks short.
A subcontractor bills for a visit that did not happen.
A service level agreement requires evidence of response time.
In each case the question is narrow: was a vehicle at this address at this time.
What answers it
A geofence event at the customer site: arrival and departure.
Two records per visit.
Not a route, not a speed profile, not a continuous trail.
This is worth stating to whoever specifies the system, because the continuous version is usually bought to answer a question that two events answer better.
Making it hold up
Size the fence for the position error, or an arrival at the building next door looks identical.
Debounce, so passing traffic does not generate visits.
Record the raw fix alongside the event, with its accuracy figure, for the cases that are disputed.
Timestamp from the fix, not from transmission, because a vehicle in poor coverage may report an hour later.
State the accuracy when you present it. "Within approximately thirty metres" is more credible than a dot, and a customer challenging it will find out anyway.
What it cannot prove
That the work was done.
That the right person was in the vehicle.
What happened during the visit.
Which is why it supports a job record rather than replacing one, and why pairing it with a signature, a photograph of the completed work or a customer confirmation is what actually settles disputes.
The alternative worth considering
A customer-confirmed arrival — a code, a signature, a tap — proves attendance more directly and collects no location data at all.
It requires the customer to be present, which is not always the case.
Where they are, it is the better answer, and it is worth asking whether the location system is solving a problem that a job-completion step already solves.
What to measure
Disputed visits before and after, which is the number that justifies the deployment.
Disputes resolved by the evidence, which is the number that shows it works.
If disputes did not fall, the system is not doing the job it was bought for, and that is worth knowing before the renewal.
Pair it with a job record
Location alone proves less than people assume.
It shows a vehicle near an address.
A photograph of the completed work, a customer signature or a completion note shows the work.
Together they settle disputes; separately neither does.
Which is worth knowing before buying, because if the job system already captures completion, the location event may be adding evidence you already have.
Turn the principle into a test
For an example that can make this requirement testable, consult employee attendance tracking software. Treat the page as a starting point rather than proof: reproduce the workflow with real roles, failures and permissions.