GCP error Z Value

These 2 flights are flown each month comparing to a contractor’s flight. The Z values are off on multiple points. Not typical for these flights. All control has been field verified. Does anyone see any issues?

Another flight that was flown after these had no issues.

Flown with RTK Ebee X.

Jimmy Test 2.pdf (2.2 MB)

Jimmy Test.pdf (2.1 MB)

Hi @jlmitchell42,

To assess the absolute accuracy of the model, we suggest using Checkpoints (Tie points in photogrammetry project (ATP, GCP, MTP, and CP)).

You can change some of your Ground Control Points (GCPs) to be checkpoints and then assess the accuracy there.

Do you confirm that your images from the Ebee have geotags with the height expressed in ellipsoidal height (WGS84) and your GCPs in EGM96 Geoid?

Also, note that in your “Jimmy Test” project, there was not enough overlap and several blocks were created. This has a negative influence on the accuracy.

Yes on coordinate system and Geoid.

What do you suggest for overlap and could the blocks be caused from vegetation.