My GCP file had some property corner shots that were near trees. The accuracy report showed these with a very high delta z of up to 14 ft. However, they were actually very close to the classified Ground surface.
Is there a reason for this?
I’ll remove the odd ones, but it seems the Accuracy is not comparing to Ground
I removed the property corner points that were near trees. How do I rerun to get an updated Accuracy Report?
This is a good question. Sometimes my GCP’s will read like .1 off -.02, .14, and then like 16 feet. The point cloud isn’t off 16 feet in said spot.
@FabreEngineering Sorry I missed this question.
The GCP report will first attempt to compare each GCP to the ground classified points to get the delta z. However, if there aren’t enough ground points near that location then it will run the gcp report against all the points (ground and non-ground). If it does the second processing and the GCP is near a building or a tree then the gcp delta z may include points on the tree or building.
We added a few new features since this question was asked. For GCPs you have the ability to set a GCP as a checkpoint or to disable a GCP. If you set a GCP as a checkpoint then all checkpoints will be grouped together when running the accuracy report. This means that all statistics will be calculated for all GCPs and all checkpoints.
If you disable a gcp or checkpoint, then it will still be displayed on the Accuracy Report, but it wont be included in any of the statistics.