We would like to share with you very simple find we did during our operations. Making reusable Ground Control Points (GCPs) for aerial photography and photogrammetry.
We spend a lot of time testing and tuning our Universal Ground Control Software U[g]CS in a real world scenarios.
For aerial photography and photogrammetry you can rely on modern software like Pix4D, Acute 3D and other to produce good results without ground control points. If good is not enough and accurate 3D model or digital map needs to be rendered you always need GCPs.
We started from “classic” crosses made from painted plates of cardboard, wood and plastic, but they proved not to be practical in every situation and all weather conditions we encountered.
And finally we found that best material for small GCPs is simple ceramic tiles:
For each GCP you need 2 black and 2 white tiles with mat surface. Glossy has reflections and does not work well.
They are absolutely water (rain/snow), wind and mud resistant. Can be easily transported in car and reused almost forever. Until human error takes its toll and you drop them on rocks or hit hard against a car.
Tiles with 40X40 cm size proved good for making shots from up to 100 meters.
This is a shot taken from approx. 50 meter altitude with GoPro:
Zoomed in part of the frame above:
Good luck and safe flights,