Do I need to have geo referenced images for the split-merge?


I’m pretty on ODM, so please pardon my naive question.
I’d like to assemble a rather large image set and it looks that split-merge is the route to go.

From what I understand, this approach builds some optimal subset with overlap.
So, I assume that I need to have geo-referenced imaged.

Is my assumption correct?

We are working on underwater archeology, so we do not have GPS exif tags. However, it is possible to post process the images to add such and I wonder if that is worth the effort.




No such thing as naive questions!

Yes, part of the split/merge, as you noted, is the geographic binning of images to ensure proper overlap between the submodels.

I think if you need the split/merge pipeline, it might be beneficial to do your post-processing to get geolocation information.

If not, you could always manually chunk groups of images into separate tasks and then combine in post, but be aware that a naive reconstruction may not have the level of detail you require as the GSD estimate may not be anything close to what it really was in-situ.

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Thanks a lot for the answer, super clear and makes sense.
As our picture are shallow under water (archeology orthophotos), we are devising a solution to post label the photos with GPS coordinates. At least that part looks like working.



Ahh, excellent!

We also have the concept of the geo.txt file for manually georeferencing photos, which might be simpler or possibly more flexible in your use-case?

If nothing else, you don’t need to modify the source images and you could potentially iterate multiple times with different geo.txt files rapidly.

Thanks for the pointer, it could prove to be useful

It was just some python to write to make the annotations back in the images, nothing super fancy. GitHub - terra-submersa/coordinates-label-photos: Post process to add GPS coordinates to photos

BTW, thanks. I just discovered ODM by chance and it is really a great tool ! Congratulations.
We cannot wait to dig more in.



Ah, very nice! Glad you made it open too for other folks to poke at :slight_smile:

Glad you are enjoying ODM!

Also really great to see more and more folks working with ODM in this space.

I’m sure other folks would love to see some of your work, so please consider giving #the-showroom a look to post in :slight_smile:

We will, when we have something tasty enough to show !



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