Georeference old aerial imagery

Hi everyone,

First time posting and apologies if this has already been addressed. So to explain my problem and what I hope ODM can help with.

I have over 6000 Aerial Images, scans of original image plates. The imagery from the 50’s 60’s and 70’s.

What I was thinking, you all can advise on this, was that I reverse engineer the flight plans (I have scanned paper index’s for all imagery) then use ODM to Reference the Images, I’m not proposing to Ortho correct or anything as there’s only 20% overlap at most, but just to reference them properly to a decent accuracy. The plan is to make them more useable and accessible to the Public.

If you could advise of guide me in this I would appreciate it.

Regards and Thanks in advance,

Richard.

2 Likes

Welcome, Richard!

Sounds like a great project, and I like that you’re looking forward to how they could be used in the future by the public!

I’m not sure we’d be able to process the images fully with only 20% overlap. That’s quite low.

From what it sounds like you want, you just want to geotag each image so they could individually be loaded georeferenced into a GIS or map viewer, right?

Hi,
Thanks for the welcome and responding. Our Plan would be that the imagery becomes freely available to the public. At the moment, the imagery isn’t generally available as its hard for people to find what they want.
Geotagging the Images would not really be enough, what we want to do, is on a web viewer allow someone to zoom into their AOI and click on an index covering where they are interested in, then to allow them to view/preview the Imagery and download it if they wish. It would also be our wish to be able to show comparisons between more modern imagery and the older imagery. This would allow the casual, curious user can come in and look at the information in the viewer and those looking to utilise the data for other reasons can also download the data for their own use.
Im not looking for a perfect match, something in the 1:5000 – 10000 scale range of accuracy if a user wants something more accurate, they can download it and manually georeference the Image.

1 Like

Mmm… I’m not entirely certain if WebODM would be the right avenue for georeferencing the images, since that won’t happen without a proper reconstruction (or input geolocation via a geo.txt likely).

I’m wondering if maybe the UI of dronedb.app might not be more along the lines of what you’re looking for in terms of displaying your data.

As for the geotagging, GeoSetter on Windows, or maybe GPSCorrelate or GeoTagging for Linux might help you batch-tag the images if you can construct a GPX file.

Hi @RicheMcD,

You may want to try Georeferencer or Freehand Raster Georeferencer in QGIS.

1 Like

Hi @israelbar
I’d not seen the freehand georeferencer, I will have to look into it.
Thanks for that, it will definitely be worth a look!
I was trying to avoid manually having to do this, but it looks like that’s what we are facing.
Thanks everyone for your feedback!!

2 Likes

Hi @israelbar and @Saijin_Naib,

Just a little update, the overlap in the images is better than we thought, there’s a 60% overlap along flight path with 30% overlap form adjacent flightpaths.
@Saijin_Naib You mentioned input geolocation via geo.txt, I was wondering if you could elaborate on that a little for me.
One last Question, Is there a way to create a flight Path? One which could be fed into ODM?

2 Likes

https://docs.opendronemap.org/geo/#image-geolocation-files

We don’t need the flight path, just the image locations, so with the geo.txt we should be able to try to process the images.

That being said, overlap and sidelap are both quite low and likely will not reconstruct well, unfortunately.

This topic was automatically closed 30 days after the last reply. New replies are no longer allowed.