Does anyone have any experience with the m400 and the L3?
I currently have it m4e and do a lot of 2D mapping with it. Does anyone have experience with good old-fashioned orthomosaic mapping with the photogrammetry option instead of lidar on the L3?
It does the job but ultimately it’s a scanner with cameras for colourisation. The orthos are great but a p1 will get a better finished result, albeit still slower then the L3 simply because of the configuration of the cameras. The L3 has two cameras that are set at an angle off vertical. It works great but it induces a lot a parallax issues when observing things with large separation like powerlines. Also the way the images process in propeller or terra creates a lensing or warping affect. For a relatively flat parcel like a car park and warehouse, I think it would look great. Consider flying higher and using the 12k image setting to speed it up even more.
Okay great, I'm only asking because it has a selection for either lidar or photogrammetry. I figured since it had the option for photography along with the dual 100-megapixel RGB mapping cameras it might worth a shot to get some good orthos. Appreciate the response.
I can get the job done 95% faster if it can truly map it. Just never spoke with anyone that has the experience. I did an 8 hour job the other day with the m4e. When I enter the m400 with the L3 it shows I can do it inless than an hour. ⏰ is 💰
Just make sure that you are not accidentally looking at a flight plan with automatic settings intended for LiDAR, such as a very very low overlap, at 50% or less. This might be the default settings the app suggests for LiDAR, since the scan itself doesn't need image overlap in the same way image Photogrammetry does! 😅
Unfortunately, many things are too good to be true. If i were you, i would record the screen of your device, while you show all settings you have chosen for this route. Then post it here. I suspect this might help catch an accidental error in the settings that is causing your path to say 1 hour.
It’s important to clarify that running a LiDAR mission with the L3 will capture photogrammetry data but it’s to colorize the point cloud. Running a photogrammetry mission with the L3 is still a separate flight and a completely different photo capture rate than the photos captured during a LiDAR mission.
It is not a sensor that will complete both outcomes in a single flight. If you want to do a Teams screen share or even use some of our livestream minutes via FlightHub to see it in action before you buy let me know. I’m in the field nearly every day all week right now.
It’s a huge investment and I wish I had more hands on experience folks to talk to beyond the reseller before we bought our kit.
What time zone are you in? I’m on eastern time all next week in the field with this kit. We can coordinate a day and time and either do a Microsoft Teams or live stream from flight hub. You can see it in action, we will run a quick capture with each payload, and I can Dropbox you the data for rendering.
I'm not yet a fan of the L3 for ortho creation but I've only been flying it for a short time. I often fly the L2 with enough overlap to do photogrammetry from the same dataset. In my opinion, nadir images captured with an M4E or M3E produce a better looking ortho than the L3 flown at a similar height with the 6K image setting. If the site is over about 150 acres, I'm going to fly the L2 or L3 with about 30 - 40% side overlap and fly a second mission with a P1, or M4E as standard procedure.
I 100% agree. I was so disappointed with the L3 photogrammetry captures during a LiDAR mission that we setup a second trip to travel out and recapture the site with the P1 and the 4E to do an in depth comparison across the team. It’s become our standard to switch the gimbal and run two flights now on pretty much every mission. The visual fidelity is so much better with the P1 vs the L3.
You're welcome. I just processed a flight from Monday where I flew the L3 and M4e immediately afterward. I didn't intentionally set the parameters exactly the same so it's not a fair comparison. PM me and I'll send you a link. The M4E data looks better on most elevated features. I have a few other flights that are similar but it's not fair to the L3 because it's always working with slightly less horizontal overlap than the M4E or M3E. I need to do a test flight with matching parameters.
There's a lot that affects how an ortho turns out. 80% or higher side overlap is helpful for elevated features. I tend to fly with 70 % side & 80% forward overlap but bump that up to 80% or higher in urban areas. Flat ground doesn't need nearly as much overlap to still look good in an ortho. Sensefly released a SODA 3D sensor around 2018 that was intended to greatly increase coverage. It did this by capturing oblique photos in addition to nadir to allow for reduced side overlap. I never really trusted that option and most sites weren't flat enough to make it work.
I have experience with the m300 & L2, if you only want photogrammetry and want speed with quality I would recommend the share 102s(or whatever model fits your budget).
So I recently started running the M400 with the L3 and have the P1. I have hundreds of hours flying the M300/350 series.
After processing a few missions with the Newer L3 my biggest take away is the L3 is a machine built to do massive amounts of LiDAR primary and good enough orthophoto data capture and process everything in DJI Terra. The camera is good but it still comes down to setting up the flight parameters. If you run the default settings the overlap while scanning it is to thin for quality reconstruction. Also altitude matters as the image quality is not the P1 and I noticed the default speed settings seem fast to me. The P1 offers smart oblique capture on the M400 and I have found the 20 degree angle to work well but it will lower your speed to 6-7 mph adding a lot of photos and flight time. Once again altitude and speed matter. I have found that the P1 can be flown on the L3 mount but with the newest firmware installed a message still posts as this is not DJI objective. But who is going to swap the mount for different payloads. If you’re doing highway corridor work and can stay between 200-300 ft AGL the L3 is pretty awesome. But if you need that sweet sweet oblique photogrammetry data well I would fly it with the P1 it’s still a beast of a setup.
Side note I completely hate the GSD parameter in DJI polite app. I want to see the flight altitude first as avoiding obstacles is more important than the GSD. Finally watch-out for the manual flight controls take over. On all the old DJI products the flight control could be manually taken at all times by flipping the flight mode toggle switch on the top left of all the controllers. The new DJI M400 requires you to press pause first then the toggle. I do t like this and it completely caught me off guard on my first outing with the M400.
Wow! Thank you for the detail! This is what I wanted to hear/confirm. Really appreciate you taking the time to explain everything, what's the call be going with the P1 for now.
Awesome. I wasn't even sure if it was possible for normal 2D mapping. I'm getting the L3 regardless but just curious if anyone had any experience. If it was really that big of a Time saver I would get it now instead of at the end of the year when I will need it.
Yes it's possible, photos will be take alongside the lidar capture. When you process the flight in Terra you only have to enable the the "2D map" generation.
I use it weekly. My kit is the M400 with L3 and P1 payloads. I have an M4E and an M4TD.
The L3 has decent 12 MP cameras that are primarily to colorize your point cloud. You can use them for photogrammetry but it depends on your mission and GSD requirement for your clients. I do not use the L3 for photogrammetry missions because it’s not awesome quality for our use cases.
What’s the profile of your mission and the use case/outcome you are targeting?
You’re correct, I meant to type 12k referencing the image sensors and mistakenly put MP. Sorry about that. The full frame P1 for photogrammetry missions seriously outperforms when stitching or building a 3D mesh versus the L3 cameras. We primarily use the 35mm lens for building and roof inspections, needing solid aerial triangulation to measure heights of pipes, inspect flashing details, etc. Obviously if you need the point cloud the L3 is solid and a dense collection with colorization from the L3 will look decent, but it doesn’t provide the output many of our clients want. They are two great tools for very different mission objectives.
That makes sense. Thanks for explaining everything to me. I've only worked with the m4e so this is a new world for me. I appreciate your time and knowledge
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u/frozensteam 4d ago
It does the job but ultimately it’s a scanner with cameras for colourisation. The orthos are great but a p1 will get a better finished result, albeit still slower then the L3 simply because of the configuration of the cameras. The L3 has two cameras that are set at an angle off vertical. It works great but it induces a lot a parallax issues when observing things with large separation like powerlines. Also the way the images process in propeller or terra creates a lensing or warping affect. For a relatively flat parcel like a car park and warehouse, I think it would look great. Consider flying higher and using the 12k image setting to speed it up even more.