I’m trying to map a forest in its winter state. I want to capture the contours of the trees. I flowed twice with my mavic pro. The first time I flew at an altitude of 150 meters and the second time at 100 meters. During both flights I applied more than 80 percent overlap.
The problem is that the branches are difficult to see in both the drone photo and the developed orthophoto. This is probably because the color of the branches resemble the background. See the drone photo below.
Anything less than about a 10cm width is going to be hard to capture with photogrammetry. Especially with a 12MP Mavic Pro. What is the purpose of capturing the level of detail you are describing? I believe 150m is a violation of airspace regulation almost anywhere that has regulations and even 100m is far to high to capture anything smaller than the size mentioned unless you have a custom rig or a long focal length lens. IMO it’s not feasible to capture even smaller branches and produce usable data. Maybe if you were at an altitude of 50m but I think the best you are going to get is some undiscernible points and the mesh is going to ruin the orthomosaic.
I want to be able to trace the outlines of the tree crown. Perhaps you are right and is mapping this forest is not possible for my purpose. I will try two more times this week at 70 meters and at 50 meters. I will post the results on this forum.
I flew again at 50 and 70 meters altitude. I was not very pleased with the end result. It remains difficult to get a good picture of the branches of trees, in which you can see which branch belongs to which tree. maybe it’s time for a better drone.