Keep invalid coordinates from appearing as real vans
Missing coordinates are coerced to zero, placing a depot van in the ocean. Validate telemetry before rendering and explain vehicles with no usable position.
- Focused work estimate
- 1h 15m + prerequisites
- Priority in the scenario
- High
- Engineering practice
- Input validation · Geospatial data · Data quality
Estimated field mix
- Data engineering40%
- Real-time systems30%
- Frontend30%
Field percentages are editorial estimates of the ticket's engineering focus. They total 100%; they are not measured time, proficiency scores, or ownership evidence.
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Project context
The fictional Cedar delivery depot dispatches vans through a browser map and accessible list. Synthetic telemetry arrives through a gateway with device sequence numbers. This is operational fleet software practice; no real driver tracking, employee scoring, or routing safety guarantee is part of the project.
Setup prerequisites
- Synthetic vehicle telemetry with device sessions and sequence numbers
- Dispatch assignment and authorized region API contracts
Preceding work
No earlier ticket is required. Complete the project setup above.
Acceptance criteria
- Latitude and longitude must be finite numeric values within documented geographic bounds.
- Missing or rejected position data produces an unknown-location state in the list.
- A valid zero coordinate remains valid and is not treated as a missing value.
Implementation constraints
- Keep vehicle identity separate from location availability; rejecting one fix must not delete the vehicle.
Verification to include
- Render valid zero latitude and a normal depot position correctly.
- Send null, a numeric string, an out-of-range value, and non-finite coordinates; none becomes a plausible marker.
Deliverables
- Telemetry coordinate parser and invalid-position fixtures
Rollout and recovery
Validate traces before map display; hide invalid markers while retaining unknown-location list rows.
Value of the work
For the engineer: Practice geospatial boundaries, stream ordering, snapshot recovery, and concurrent operational commands.
For the team: Inspect whether a developer keeps dispatch decisions grounded in current authorized data and exposes uncertainty during outages.
Evidence boundaries
Outcome Evidence: Tests, patches, and runbooks are requested deliverables. They become Outcome Evidence only through a qualified Mission and immutable Evidence IDs.
Ownership Evidence: Independent adaptation must be observed under a declared verification policy and cite immutable Evidence IDs. Completing a planning ticket establishes no Ownership Evidence.