Zenmuse L1 -> DJI Terra -> PIX4Dsurvey

[seiichi_takayama]

I can get dataset of Zenmuse L1, the latest product of DJI, LiDAR equipmet.

I tried to analyze dataset by ‘DJI Terra’ and output las file.
Next I tried to import las file to PIX4Dsurvey. Well done !
(No need to insert information of epsg code)

Attached image is result of terrain filter.

(Overview)

(Before remove Non-terrain)

(After remove No-terrain)

[Nate_Moore]

Thanks for sharing this @seiichi_takayama ! It looks really nice, and I’m glad the terrain/nonterrain is working so well for you. Did you make a TIN from the smart grid? How did it come out?

[seiichi_takayama]

Hi, @Nate_Moore
Thank you your reply.
Sure, I can make smart grid point.

And after that, I can make TIN.

Seiichi Takayama

[aer]

HI @seiichi_takayama. I recently got the ZL1 and I have already tried the first flights with it. I processed in DJI Terra, but I can’t import to PIX4DSurvey because it points me to PIX4Dsurvey support only projected coordinate systems.

These are my first steps in LIDAR. Can you help me see what I’m doing wrong, please?

[Nate_Moore]

@aer We’ve had some trouble reading the coordinate system info from Terra outputs sometimes, but have been working on it. Could you possibly share the point cloud with me and I’ll try in a draft version of PIX4Dsurvey? Thanks, Nate

[seiichi_takayama]

Hi, ＠aer
I do not know why error had displayed, sorry.
Is your selected coordinate system special ?

if you know epsg code, please try LASTools.
Please check this thread.

Select Coordinate System When Import Las

Greetings. When I import las for new project , error displayed. [image] Imported Las file is Edited by TREND-POINT (The most famous Point-Cloud Editing Tool in Japan.) I know Pix4Dsurcey need coordinate system information in las file. But I don’t know how to write coordinate system information into las file. I want to select coordinate system when import las file. Best regards. Seiichi Takayama.

Best regards.
Seiichi Takayama

[aer]

Hi @Nate_Moore, attached Dropbox link to download a point cloud processed in DJI Terra. Transfer - Dropbox (357.7 MB)

Please, tell me how you find it with PIX4Dsurvey, and thanks for your time.

[aer]

Ty @seiichi_takayama, I will try LASTools.

[Nate_Moore]

@aer You should try pix4dsurvey 1.17.1! In my tests, everything works nicely there. The difference is that we’ve now added coordinate system transformations for imported geographic files like yours. Ideally, import that .las into an existing Survey project.

Let me know how it goes!
Nate

[aer]

Hi @Nate_Moore Nate_Moore, everything worked fine. I used version 1.18, importing the LAS generated in Terra (after adjusting the coordinate system and geoid). Pix4Dsurvey recognizes the coordinate system and imports the file. Here is an example with a low-density point cloud.

[aprflytechstore]

Hello there,

I’m trying to understand if I can use a ZL1 for forestery inventory purpouse, is there anyone that can share some point cloud generated with L1?

It will be really helpfull to know also the acqisition parameters of the flight (height, overlap, repetetive or not and first doble or triple return mode)

Thank you
(@seiichi_takayama @aer @Nate_Moore )

[aer]

Hi @aprflytechstore. We have some files from L1, but it was not our objective to fly over forest biomass. If you are interested, I could share the flight file with you, so you can see if it helps you evaluate what you are looking for.

[duonglq]

The link has been expired, can you reshare again?

[Nate_Moore]

Hi everyone,
Just coming back to the parent topic here of the L1 and other lidar datasets. Did you notice that we brought a lowpass option to the grid of points creation in PIX4Dsurvey?

That shows (in pink) a set of points taken from the lowest decile of an aerial lidar dataset. This didn’t even use the terrain classification as a helper, it was from the full set, and gives a really nice way to separate your ground under forest canopy from the trees. Of course, if it works in a forest, it’ll be good in other scenarios, like patchy grass, under scrubby bushes, tree branches, overhead wires, etc - give it a try!
Nate

[aer]

I don’t have it available. Dropbox account does not save expired links, only in professional accounts

[aer]

Pues, funciona muy bien.