How to map and measure Pole and Tower Structures

 
Important: Pole structures such as power lines are difficult to model as they are very thin and tall. Besides, this kind of structures is often made of reflective materials, and therefore they often appear white in the images and very few keypoints can be detected on them.

 

There are 2 main possibilities to map pole and / or tower structures:

 

Images taken from above (nadir)

A very high overlap is required (more than 90%). 

If the structure is not fully reconstructed in the rayCloud, it is possible to digitize it by creating polylines and by refining the vertices of the polylines in the images.

 
Information: For more information about how to draw a polyline: How to draw a Polyline in the rayCloud.

Using a fisheye camera may help to capture the images because of the wide field of view of the lens.

 

(Recommended) Images taken from the side (oblique)

It is recommended to fly close to the structure and as flight plan, there are several possibilities:

  • Turning several times around it while changing the altitude, following a spiral.
  • Making several circles around the object at different altitudes.
  • Making several vertical length from the bottom to the top of the structure, at different positions around the object.

In all cases, it is needed to have a very good overlap between images (at least 85% frontal and side overlap).

The camera should have a 45 degree angle pointing to the ground. By pointing the camera to the ground, less sky content is visible on images which make them easier to match and it provides a better model. For more information:

 

Video Example

 

Video Tutorial

 

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  • Alessandro Bedin

    Hello, I have to map the exteriors of an offshore platform, then in the background instead of the ground there is water. Can the water cause any problem when building the orthomosaic like the sky does? 

    Edited by Alessandro Bedin
  • Kapil (Pix4D)
     

    Hi Alessandro,

    Images that capture only water might not be calibrated (optimize the internal and external orientation of the camera). The reason is that it is very hard to find keypoints on water surfaces (water is very uniform). Even if keypoints are found, it is very hard to match them between images, as these points are not static. This will have an issue as you are expecting. 

    However, you can also edit the unwanted point cloud to clean it in case of any issue. For more information, I would recommend you to go through our support article on How to edit the point cloud in the rayCloud.

    Thanks,

     
  • Dennis Smith

    Is it possible at all with Pix4D to capture distribution and transmission conductors using photogrammetry? I understand it is difficult but impossible? 

  • Dan Harmening

    I too am very interested in mapping the Conductors in Pix4D point cloud.  I am waiting on my data from a large file and will apply the information gathered.  Any further details would be great!

  • Holden (Pix4D)

    Hi Dan and Dennis. This is possible depending on the level of detail desired but requires very high overlap and advanced workflow knowledge to accomplish. You can reference the principals above in order to give the best chance of success and share your results on the community to help others.

  • Jackson Miller

    Hello Holden!  Im happy to know that this is possible! Can you give us some pointers on the workflow? Is there someone with Pix4D who has had success with this who might be able to help us out?  It looks like we should be able to add tie points in the images on the conductors and that will generate point cloud for those points. Is that right? 

     

    Dan, have you had any success with the data you were waiting on? 

  • Marco (Pix4D)

    Hi, Dennis Smith, Dan Harmening, Jackson Miller,

    Have you heard about our last release Pix4Dscan and Pix4Dinspect?
    You might be interested into it:
    https://www.pix4d.com/product/pix4dinspect-inspection-asset-management-software

    https://www.youtube.com/watch?v=sioI-TkWnQQ

    Best

    Edited by Marco (Pix4D)
  • Dennis Smith

    Hello Marco,  I have heard of these new releases and we are very interested in trying them out. However, we are having a difficult time trialing your software.  I would love to be able to speak with someone at Pix4D but have not had any success at all contacting you guys.  I have tried the phone number several times which directs you to submitting an email/ service ticket of some sort that I have filled out but never hear back from your company.  Because of this I have been hesitant to purchase your subscription because I am uncertain I will ever be able to talk with anyone should I have questions. We have a lot of questions concerning your software; we will be flying a matrice 600 with several different payloads including LiDAR and a thermal camera as we also have a thermography certification. We also run a Leica BLK 360 LiDAR scanner on the ground and we are interested to know if we will be able to combine the point cloud data with the point cloud we generate with photogrammetry from the drone. Primarily, we will be flying distribution and transmission lines and substations. We will also be doing some mapping for large ranches in Texas.  I believe we would benefit greatly from using your software, however, it would be great to be able to speak with anyone from Pix4D before we make the decision - if anything we simply need help getting the trial to work! It looks like we need to use Pix4D mapper in conjunction with these new releases but we cant get Pix4D mapper to work - it is telling us the license is disabled. I dont know who else to contact so I am hoping, Marco or Holden, I could possibly talk with one of you or someone you direct us to.  We will be flying a job today and will have to use Drone Deploy, who answers and returns phone calls quickly! I really hope to hear something soon, as we have jobs lined up and need to use capable software. 

  • Marco (Pix4D)

    Hi Dennis,

    For now most of our offices are closed due to the current situation. That's why we might have lost your call.
    As we have released four new products on the 31st, our response time might take longer than usually. However I have asked to our Sales department to get in touch with you.
    As a side note, Pix4Dinspect does not support LiDAR data sets.
    But Pix4Dsurvey does! This is our new vectorizing software that is meant to bridge photogrammetry and CAD.
    https://www.pix4d.com/product/pix4dsurvey
    Only Pix4Dsurvey works in conjunction with Pix4Dmapper, but not only. Any point cloud can be imported however importing a project from Pix4Dmapper gives the opportunity to vectorize on both point cloud and images.
    Best regards


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