Comment by lazide
It depends a lot on the terrain type - highly repetitive terrain requires higher overlap. It does sound like they have some broken setting somewhere though.
It depends a lot on the terrain type - highly repetitive terrain requires higher overlap. It does sound like they have some broken setting somewhere though.
Just curious, why do you have to survey repeatedly? Are you monitoring something changing?
The area was partially clearcut about a decade back. Some areas are due for brush management and some for commercial thinning. Additionally, because it is alpine and contains a stream used by fish for spawning, it is interesting to see the variations in snow load and water flow in the stream year over year.
So there's at least a reason to get out each winter (snow load), spring (melt/brush growth/flowers), and summer/fall (stream health/identify trees once brush loses leaves).
I also like seeing if there's trees in stands dying at an unusual rate, which might indicate pine beetle infestations or sickness that I'd need to take care of.
Also, it's a fun hobby and a cool dataset to flip through.
It's heavily pine forested mountain areas. With a 65-75% overlap, the SFM algorithms struggle to produce sufficient details. Additionally, because of the verticality of the terrain and very tall pine trees there's a need to have multiple angles to generate a good orthophoto. So the grid is denser than other environments for a reason. I'm continuously updating my flight plan based on the results generated -- squeezing density up/down based on observed results.
The 4 hours is an overestimate, it's probably genuinely closer to 3 hours flight time.