Thanks for the support. This is actually part 3 of a much larger project. With GCP the project looks fine. We always use GCP and we put extra points on both sides of the corridor for the overlap area. We make the overlap area more than 1000’ long with 6-8 extra GCP. We also profiled the roadway with a vehicle as a rough check and we are very happy with the resuls. We do lots of corridors for volume measurement, pre and post construction. I have probably done 30+ projects and have never seen one process like this before.
One problem noted in the processing was the Absolute Geolocation Variance was really large in the Y value ( +250’). The other two phases of the project were all less than 10’ for the X and Y values. Elevation differences are usually large but usually consistent between phases of a project. I believe that this would have to be a problem with the EXIF from the drone.
We have saved some contractors a lot of money on several projects by having accurate topography when there is a dispute over volumes. After catching a volume error worth several million dollars, the contractors are much more willing in invest in using this service.
Again, thanks for your support.