Ground control and RTK for accuracy

Photogrammetry reconstructs the shape of a site very well on its own. What positions that shape correctly in the real world — the absolute accuracy — is your control.

RTK / PPK

A drone with RTK (or post-processed PPK) tags each photo with a survey-grade position. For most mapping work this alone gives strong, repeatable accuracy with no ground work.

Ground control points (GCPs)

GCPs are marked, surveyed points on the ground. They anchor the model to a known datum and let you verify accuracy independently. Use them when a deliverable will be relied on for design, legal, or as-built purposes.

Checkpoints

Surveyed points you don't use in processing are checkpoints — they measure how accurate the result actually is. DroneFlow's checkpoint tool reports the residuals so you can prove the number, not just claim it.