We want to develop a technique to be able to measure water levels in archipelago and lake areas and compare over time.
I don’t know if this at all would be possible and appreciate any input what you guys think?
Question:
From the initial testing we have done (se attached image) I see the first problem we run in to is that Map Engine does not interpret the water as a level surface which I think we can assume it actually is This makes it har to accurately monitor the level. What can we do to make the DSM read the water as a flat surface?
The equipment we are testing with is a Phantom 4 Pro and we use polarizing filters to minimize glare from the surface. We don’t have the option to use GCPs.
The goal is to be able to measure the change in water level with a ± 10 centimeter/4 inches accuracy (we don’t need to measure water level in reference to absolut elevation)
Could you explain a little more about what you are trying to collect? When I do water levels, since water is level, you just read the level at the bank. It should be the same all the way around. Next step is that I bring the point cloud into an editing software and cut out the area inside of the perimeter of the bank. In reality it is this way, but with a drone flight errors that occur will make it appear that the water level might be different around the bank. I don’t see why you couldn’t sit gcps and just over fly the perimeter of the water a little bit. This would at least give you a corrected surface overall. Another thing that I have seen someone do is to drive a pole into the water if it is not too deep with a small placard on the top. A smaller pole is inserted and a placard is mounted at the top. If the right materials are used the placard will float on the water surface this would give you checkpoints, but would still not completely level the model from photogrammetry.
This makes it har to accurately monitor the level. What can we do to make the DSM read the water as a flat surface?