Hey Droners,

I have a question about measuring tree height in dense rainforest using drone-mounted LIDAR. We have a Matrice 300 in my laboratory, where we use it on research involving collecting the tippy-tips of tall trees. It's a miracle-- it gets done in minutes safely what used to take us days with all the risks involved in climbing tall trees in remote locations.

Here at my institute in Mexico, we oversee several protected areas of dense rainforest on rugged terrain. For various reasons, we need to identify the tallest trees in our parcels of land. Doing this on foot is extremely time-consuming and it's hard to know if you have thoroughly canvassed an area. I am wondering if we could use our Matrice to help locate candidate tallest trees. We would then visit the candidate trees and measure them directly.

Unfortunately, our remaining rainforest patches aren't large, but the terrain is rugged and getting into them is a whole expedition. We would need to cover maybe a square kilometer using LIDAR every 6 months or so. We are hoping to find trees >80 meters (>250 feet) tall in some of the steeper and more inaccessible canyons protected from winds.

Would the Matrice lend itself to this? We can get up to the edges of most of our rainforest patches on dirt roads or in pastures, so launching into them should be doable. Any suggestions on whether this would be feasible, and if so, what gear and software you would recommend? Thanks

That would be easy with LiDAR. Which LiDAR system do you have?

If we had to do such operation, we won't be using DJI Matrice but a fixed wing EVTOL. In particular the Quantum Systems Trinity : https://quantum-systems.com/use-case/guatemala/

PS: we are not reseller or commercially bound to QS. "Just" a UAV operator.
Why Trinity vs Matrice:
- better endurance and speed
- ease of use
- high quality Lidar

Price is...the main pain point, it's near double/triple the Matrice.

+1 for the QS Trinity Pro w/ the Yellowscan/Qube LiDAR. Not cheap and has its quirks, but a better system & not bound to sub-par processing workflows.

Taking a guess here, but unless you (the drone operator) have the correct local authorisations you couldn't fly the fix wing further than 500m from you anyway (obviously check your aviation authority regs).
So the bigger question is, can you actually/compliantly fly the Trinity Pro, if you could afford it? If you're doing 1km square twice a year might be better paying a local company to do it for you.
The Zenmuse L2 lidar is apparently compatible with the M300, but you are initially tied to DJI Terra to produce a .las file. You can use the free version for that though, but you'll still then have to pay for some other software to process, like LidarViewer Pro by Routescene. The L2 is no-where near as good as the Yellowscan, but it's about a third of the price! You get what you pay for, but it is a decent entry level lidar. I fly it on an M350 RTK.

MappingPro Posted at 9-16 12:49
That would be easy with LiDAR. Which LiDAR system do you have?

That's great. The question I posed in my post was "what [LIDAR] gear and software you would recommend?"

AR_AirPrecision Posted at 9-19 01:02
If we had to do such operation, we won't be using DJI Matrice but a fixed wing EVTOL. In particular the Quantum Systems Trinity : https://quantum-systems.com/use-case/guatemala/

That's great for you, but not what I was asking. I was asking what LIDAR hardware and software folks might recommend given that I am using a Matrice for my own reasons that don't require explanation/ discussion with anyone. So, I'd appreciate any replies to the question I asked.

Jubba Gash Posted at 10-10 08:27
Taking a guess here, but unless you (the drone operator) have the correct local authorisations you couldn't fly the fix wing further than 500m from you anyway (obviously check your aviation authority regs).
So the bigger question is, can you actually/compliantly fly the Trinity Pro, if you could afford it? If you're doing 1km square twice a year might be better paying a local company to do it for you.
The Zenmuse L2 lidar is apparently compatible with the M300, but you are initially tied to DJI Terra to produce a .las file. You can use the free version for that though, but you'll still then have to pay for some other software to process, like LidarViewer Pro by Routescene. The L2 is no-where near as good as the Yellowscan, but it's about a third of the price! You get what you pay for, but it is a decent entry level lidar. I fly it on an M350 RTK.

Thanks for the suggestions!

If you only care about the elevation of the tops of the tallest trees, you don't really need LiDAR. A photogrammetry DSM or point cloud will give you the data you're after. Now if you want to see through canopy, and map understory/bare earth, LiDAR will provide something that photogrammetry can't.

Podeitor Posted at 12-16 06:56
That's great for you, but not what I was asking. I was asking what LIDAR hardware and software folks might recommend given that I am using a Matrice for my own reasons that don't require explanation/ discussion with anyone. So, I'd appreciate any replies to the question I asked.

Would the Matrice lend itself to this?
-> not optimal, VTOL are better
We can get up to the edges of most of our rainforest patches on dirt roads or in pastures, so launching into them should be doable. Any suggestions on whether this would be feasible, and if so, what gear and software you would recommend? Thanks
-> I told you what gears are better
If the answer you expect is based on what you have : there is no question here, you just look to validate your POV.

AR_AirPrecision Posted at 12-18 02:14
Would the Matrice lend itself to this?
-> not optimal, VTOL are better
We can get up to the edges of most of our rainforest patches on dirt roads or in pastures, so launching into them should be doable. Any suggestions on whether this would be feasible, and if so, what gear and software you would recommend? Thanks

To be fair, he asked if he could accomplish his goal using his existing Matrice 300, and advice on sensors and software. You offered a better solution using another platform, which could be helpful if he has the budget to consider that option. But perhaps he has no or a very limited budget, and must do what he can with the platform he has.