The image below is that of an elevation using GCPs. All but the four markers up on the red roofs are survey pegs, -mapped, measured and processed as GCPs. Their xyz are accurate. The markers’ levels within the processed map are more or less spot on and demonstrates that the software used the values I entered through the excel file.
What I can’t for the life of me understand however is how it’s managed to record the heighrlts of the adjacent buildings being up to 1.7m different to what they actually are. It makes no sense at all. What levels are outside the GCP zone I can completely accept their values might revert back to a non-GCP map, but not inside the zone and is why it would greatly assist to be able to correct other known z values of a processed map (or possibly prior to). I can’t be expected to climb up on top of a pitched roof to sit a target map down every time I want to fly. That said, I’d like to be told what I’m doing to cause such a discrepancy. I’d rather not be correcting anything.
I’m aware that I’m beginning to sound like a broken record, but I simply cannot understand how the vertical measurement of four buildings, not one, not two, can be so far out when sited immediately next to GCPs.
Again, I really appreciate the support within the forum and other staff that have emailed me.