Massive Ortho Maps in QGIS

Hi all! Does anyone have any experience with bringing in 2GB+ orthomosaic maps into QGIS? I do not have tiles, just the mass site. Thanks!

Well, that’s close to 2gb… From earlier this week. I might have bigger ones around here. Did you need it specifically over the 2gb? You can build pyramids to speed things up. This makes it smooth.


The file I am on right now is 2.7GB. I will give this a try and report back. Thanks @Brent_W!

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First pass crashed QGIS and corrupted the file. Luckily I made a copy per the softwares recommendation. I think part of the problem is that even though the image is only 82K pixel wide the resolution is 0.4in/px so it is very dense thus it gave me options in the Pyramid menu for 40k and 20k. I went down to 5k and it appears to have worked, but still takes at least 3 minutes to render with each zoom action.

I can create pyramids at multiple levels correct?

yes you can create pyramids at multiple levels.
It shouldn’t even be close to the limit for size I don’t think…

Also,which version of QGIS are you using?
Not to be rude but did it freeze and you got tired of waiting…?
or did it actually crash…
Man, am I glad you backed it up first!

Not on the absolute latest version, but one back. It actually crashed and gave me the error report notification.

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holding image datasets in large mosaics sucks in my opinion
also holding them very small tile caches also sucks

i like to chop everything into tiles that are in the 1 to 100 megabyte range per tile
then i access them in qgis and arcgis through a .vrt file

the result is that i can access multi gig image sets even on a old toughbook u1 with QGIS


I can download the 4k tiles, but the end goal of this task is to provide a PDF of the map with some overlays so tiling is actually a step backwards. I have seen many posts of GIS pros using 10-20GB orthos and just cannot figure out how. I got the second attempt to work after doing 10k, 5k and 2k pyramids, but even that process took 45 minutes.

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Thanks @Brent_W for the solution! It took 90 minutes, but I was able to build 3 levels of pyramids and it works very well now.


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