FAQ
What are Check Points?
Check Points are surveyed points with known coordinates that are excluded from SLAM correction and georeferencing correction. They are used to validate accuracy after processing by comparing the surveyed positions with the processed dataset. In Aura, these comparisons are reported as residual errors in the accuracy report.
Why use Check Points?
-
Meet surveying and geospatial standards that recommend or require independent accuracy checks.
-
Provide documented proof that your scan meets project tolerances (for example, ±20 mm).
-
Ensure validation is independent of the control points that influence georeferencing.
-
Avoid the need for third-party software or additional workflows to validate accuracy.
Can I use Check Points with control points in the same CSV?
Yes. Both control points and Check Points can be included in the same CSV file. Mark points as Check Points during assignment.
Are Check Points included in georeferencing corrections?
No. Check Points are excluded from the correction process and contribute only to validation and reporting.
How many Check Points should I use?
A minimum of 3–5 well-distributed Check Points is recommended for reliable validation. More may be required for large or complex projects.
Why not use all surveyed points as control points?
Using every surveyed point for georeferencing would remove the independent dataset needed for validation. By keeping some points as Check Points, you maintain an unbiased measure of accuracy rather than letting all points influence the correction.
What is the difference between "Before GCP correction rigid alignment error" and the "Final error?
The Before GCP correction rigid alignment error is reported after survey points are assigned but before SLAM correction is applied. It shows the initial fit between the SLAM trajectory and the survey data and may appear large in complex or extended scans.