My organization uses drones for measuring stock tanks. Stock tanks are impoundments that catch water runoff for livestock. Our goal is to determine the maximum water a stock tank can hold during monsoon events.
We have flown hundreds stock tanks, most using GCPs, and I am trying to confirm whether we should be using them or not. The way these areas are set up we often have to carry GCPs and surveying equipment long distances. Using GCPs typically adds an 30 minutes or two per stock tank (highly dependent on tank size and site conditions.
I have attempted to find discrepancies between no GCPs vs GCPs in projects and the changes often seem to be negligible for my projects. The stockponds are typically between 0.5 and 4 acres in area and I usually run two separate flights with DJI GS Pro at 150 feet with 75%-80% overlap. The projects are flown with Phantom 4 Pro V2s. One flight is normally flown with the gimble at 90% and another flight at 60%. The projects normally finish with about 600+ pictures. Also to note, we don’t care about the stock tank being accurately geolocated and only worried about the volume.
The results are so accurate that I can look up the dimensions for our vehicles and measure them in Pix4D and they are spot on.
Does anyone have any suggestions? Our projects have deadlines and we want to fly as many stockponds as we can, but using GCPs can slow down a day by hours and hours and don’t seem to give us any meaningful changes. Is there a certain flight area where the error from not using GCPs becomes significant? For example, maybe we could start using GCPS on flights over 6 acres or so? Any help on this would be greatly appreciated!