Good Day to all who read this,

My name is Benny and I am working on a extracting point elevation spot checks on a subdivision from a topographic point cloud. I have collected a flight with my Mavic 3E while it has been connected to my own RTK system, I collected my GCP's, and defined all of my Horizontal and Vertial Coordinate Reference systems when importing those points. However while I do achieve useable horizontal accuracy, the vertical accuracy is all over the place. Several Check Points have been programmed in but, it appears that while other flights fully match my vertical data when check points are added, this flight is up to 2.2' off of the check points I have.

My best answer is I have made a mistake when configuring my RTK and my GCP file and I should go out and redo the flight but, I wanted to see if there was any way to put more weight on my check points such that DJI Terra would "boot" or "raise" the surface up to them. If not I will go redo the flight but, I wanted to confirm what my options were outside of that.

Thanks so much,
Benny

Is it a consistent 2.2' Z error across your project? If so, it might just be a pole height setting or other error with your base station. If the Z error is all over the place then it may be something totally different. You can debias the Z value in other softwares but I'm not sure if Terra has this tool or not.

Luckily my collector software is kind enough to remember what shots had what heights so I can Isolate that. The elevations are fairly known, the error increases as it gets farther away from my GCP's. I think perhaps I made a mistake on GCP distribution. At this point anything I do to "fix" my data feels like trickery not reporting so I am going to go back and redistribute things. I have the ability to and I want to run a pair of flights and merge the points clouds anyways. I am still in the integration phase to add this to our surveying workflow. The idea that one guy can do a subdivision elevation as-build report to the tenth in a day is pretty nifty to the bosses.

If someone finds this later. I fixed my issue. I only needed to give a more consistent coverage of check points and then uncheck constrain with image POS data when processing things. I was in an area that has been very heavily regraded and the elevation benchmarks were set to a project elevation and needed to move the dataset quite a bit with my GCP and checkpoints since that project elevation was not very close to what observed GNSS was reporting.