Quality
How the work is checked.
Quality in survey work is a chain of checks that runs from the reference frame to the issued drawing. This page describes the checks SEC applies and what is recorded alongside a result.
A measurement without a check is an opinion. The checks below are the ones the service records describe, gathered in one place: they are procedural, they are visible in the deliverable, and none of them depends on a certificate to be worth doing.
In practice
The check chain
Where each check sits in a job, and the services it is visible in.
01
Accuracy class agreed before work starts
The accuracy class, coordinate system, datum and deliverable formats are settled at scoping. A check has no meaning until there is a stated requirement to check against.
02
Control before capture
A designed control network tied to the project datum is established first, so every later method — GNSS, total station, UAV, scanner, sounder — is registered to the same framework rather than to itself.
03
Redundant measurement
Closed traverses, repeated observations and overlapping coverage produce more measurements than the solution strictly needs. The surplus is what makes an error detectable instead of invisible.
04
Independent check against control
Processed results are compared against points that were held out of the solution — checkpoints for photogrammetric and scan work, control comparison for survey work — and the residuals are recorded rather than absorbed.
05
Corrections applied and documented
Where a measurement needs correcting before it means anything — sound velocity, draft and water level on a hydrographic job, calibration on a locator — the correction is applied and written down with the result.
06
Scope and limits issued with the result
A deliverable states what was surveyed, in what system, and what the survey did not cover. A detection drawing that does not state its limits invites the reader to assume the area is clear.
Principles
What is recorded
The paper trail a survey deliverable carries.
Datum and coordinate system
Stated on the deliverable, not assumed from context.
Control and monument records
Network schedules and point records issued with the survey.
Residuals and check results
Recorded as measured, including where they are larger than expected.
Survey extent and exclusions
What the campaign covered, and what it did not.
Ask what the checks will be before you award the work.
Tell us the accuracy class the design needs and we will set the check plan against it.