Lots of holes in the finished map

Data Processing - Discussion and Q&A
1

Seem to be getting quite a few holes in my maps and less photos used then uploaded? using a brand new Phantom 4 pro with new fast sd cards reformatted each time. Last map was really bad… and I had increased overlap to 75% as I understand that is better for shooting green spaces, max speed 25mph, also increased altitude to 310ft. Anything else I could be missing? also can you retry the upload?

2

btvmark,

Can you post a photo of the ortho or share the map? Without seeing at the final product it’s really hard to say. Most often “holes” happen when the stitch process can’t recognize any distinct features in that area, such as can happen when flying over water, etc.

You also might check this out: https://blog.dronedeploy.com/improving-the-image-quality-of-your-drone-maps-499b26e62494

Thanks,
C3

3

Hi C3,

Thank you for responding! I have uploaded (I hope) 3 photos that should explain the mission properly. Any tips would be much appreciated!!! Other than the first flight not taking any pictures the system has worked flawlessly for flight automation & taking photos, the photos seem to all be there…

image

4

Hey @btvmark,

Looks like the holes in the map are in regions of dense tree cover - this is a particularly difficult surface to map well, however there are some things you can do to (possibly) improve the result:

  • increase altitude (even) further: this helps get larger features in each image, making it easier for the photogrammetry to tie the images together; this is particularly important if the trees are very tall, or on higher ground than the takeoff point, as the drone needs to be much higher than the tree tops to get decent images for stitching
  • don’t fly on a windy day: not sure if it was windy when you flew this mission, but if it was that can make it harder to stitch the images together as the features (leaves in the trees) move about from one image to the next (a similar problem to trying to stitch water)
  • add some obliques: adding some oblique images (say 60deg, so not including the horizon in the images) can help by providing more features of the 3d trees that are causing the issues in stitching

@real_c3 thanks for your help - always appreciated!!

Jeremy

5

Thank you Jeremy! thats very helpful! it might have been a bit windy. Could you possibly go a little more in depth with adding some oblique images? is this additional images you add manually or something you do in software?

your help is much appreciated!!
Mark

6

No problem!

You would have to add the extra oblique images from a manual flight after the DD automated mission. No guarantee that this will fix the issue (just to set expectations), but it might help the chances of success.

Let us know if you get any better results and happy flying!