Basic low level photogrammetry flight

I'd like to test out a low level mapped mission for some basic photogrammetry. No higher than 30feet with my DJI MINI 2. Could someone please tell me if that sounds feasible. Flying over a smallish lake.
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Comments

13 comments

  • Comment author
    Martin Reading Dronelink Expert Dronelink Expert
    • Edited

    I would say no personally, for several reasons, the main one being at that type of height you are going to get terrible reflection off of tthe lake surface which will cause major problems when processing, this was shot with my mini2 from 285 feet and I'm you can the imperfections

    Here's a link to an online version of the Tiff https://map.openaerialmap.org/#/-0.8717090000000005,51.558863047931325,18/user/634fce5e71072f000580f871/64ca48b63473010001ab8dbe?_k=oxk9y2

     

    Any chance you can share a link to the mission you're thinking of

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  • Comment author
    Barry Houldsworth Dronelink Expert Dronelink Expert
    • Can the drone fly a mission at 30 ft? - yes
    • Will the results be useful?   Probably not.  If you are flying over a lake there will likely be frames that contain nothing but water, and stitching those into an image is generally not good. 

    But, if the lake is small enough that there will be structures that it can latch on to then it might work.  However, 30ft is pretty low so I would suggest running the mission in "verification mode" first to make sure that you are not going to hit trees or other obstacles.  This video will give info on that if you don't already know how to do that https://youtu.be/kGjG8V6XkaQ

     

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  • Thank you Martin, I really appreciate your time with looking. I'll definitely take your advice with a few practice runs. Can't really share the mission at present. Could you possibly advise on some processing software to stitch the photogrammetry please for PC

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  • Thank you Barry, excellent advice and all noted.

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  • Comment author
    Ken Kroeker

    All the comments have been spot on. The main issue is the lack of features for the postprocessing software to find matches in.  I have done photogrammetry at altitudes significantly lower than 30 feet but only when there was an object. You will need a lot of photographs as well. Here is an example model I did a few days ago processed in webodm. This was assembled from 297 photos - I have done a 2 acre site with fewer photos and this flower bed is 30 feet across.

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  • Comment author
    Martin Reading Dronelink Expert Dronelink Expert

    Thank you Martin, I really appreciate your time with looking. I'll definitely take your advice with a few practice runs. Can't really share the mission at present. Could you possibly advise on some processing software to stitch the photogrammetry please for PC

    Understood on not being able to share, as Barry said be very careful flying near trees when flying at that height, they tend to be taller than you think,,,,lol

    for processing my maps I use WebODM, the native windows installer is about £50, however if you are ok with installing manually its free

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  • Thank you Ken, this will be extremely helpful. As I have plans for similar flights to the one you describe.

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  • Comment author
    Barry Houldsworth Dronelink Expert Dronelink Expert

    Peterborough Geological Paleontological Group

    Some videos to help get you started - end to end.

    https://www.youtube.com/playlist?list=PLK_joCFfIhJ84Uu5n6EML4VHDsSpjp4qs

     

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  • Ken, did you use the Advanced Mapping - Grid (Crosshatch) Pattern and Oblique Gimbal Pitch settings.

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  • Thank you Barry, I'll take a look at those today.

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  • Comment author
    Barry Houldsworth Dronelink Expert Dronelink Expert

    Peterborough Geological Paleontological Group

    Once you are done with those, you might like to check out my Five Minute Friday series - which is a collection of videos going into tips and techniques put out on (no surprise) Friday that are (no surprise) under 5 minutes long.

    Check them out here:  https://www.youtube.com/playlist?list=PLK_joCFfIhJ8Tvsk51zHJWDtVnJ7S0Vln

    Don't forget to subscribe - I have a new one coming out tomorrow.

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  • Thank you Barry, I've subscribed and picking my way through them. That's a lot of useful information you've composed.

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  • Comment author
    Barry Houldsworth Dronelink Expert Dronelink Expert

    That's a lot of useful information you've composed.

    I often surprise myself how much I have put out there LOL.  You would think DL were paying me!

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