is it possible to crop an orthophoto generated by WebODM ?
I am a new user, and I don’t know how to do that.
Hi!
depends a bit on what you need, but a simple way is to use GIMP.
It’s a FOSS application that runs on any OS.
If you do not need the geo part of a GeoTIFF it’s super easy and you can just treat it like any image, even save it as JPEG or whatever pleases you. Crop it, rotate, anything.
In case you want to retain the geo tags (for use in QGIS or Google Earth for example) you will have to use GIMP in version >2.10.25 or later, because only those versions support GeoTIFF tags.
So just open your image, if asked choose “Layer 1”, which is the biggest layer and relates to the geo tags.
Then delete or make the areas you want to crop transparent. There are several ways to do that, there is plenty of GIMP tutorials online. I often just use the eraser to make the borders look nice.
Remember to not resize, crop or even rotate the image at all!!!
Just make the areas you want cropped, transparent.
You can still adjust colors, paint areas etc. just do not move or resize the actual shape of the image.
When you are done modifying the picture export it as TIFF and you should see a tag called “Save GeoTIFF data”.
If you did everything right and are really using a GeoTIFF image, the dialogue should look like this:
And then just export and you are done!
That is an easy and quick way of “cropping” your GeoTIFF file. If you want to step it up a notch, I am using QGIS (also FOSS) to change resolutions, do actual crops, change pyramids (preview layers inside the GeoTIFF) etc while retaining geo tags.
For that you will find plenty of nice tutorials online, make sure to follow a tutorial that is using a similar version of the software you are using. But again, for simple things I often use GIMP, for more elaborate tasks a combination of GIMP and QGIS.
Hope that helps!
Have a nice weekend!
Shiva
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Thank you very much Shiva for your very useful explanations. As I already work with Photoshop, I used this software to transform the Geo Tiff file.
Afterwards, I don’t know how to transform it into a KMZ file to import it into Google Earth Pro.
In fact, my basic problem is that when I import a KMZ file generated by WebODM into Google Earth, I have black borders instead of transparent areas, whereas on the WebODM map these areas are transparent.
I don’t know how to make these areas transparent on Google Earth.
Good morning (at least here it’s morning 
),
did not do this in a while, but I used to just open or import the GeoTiff directly into Google Earth Pro.
It then offered me two ways to import, since the images are (often) really huge.
So just try dropping the GeoTiff straight into Google Earth Pro.
Like this the transparency is kept.
Hi Shiva,
Wonderfull !!! Your method is perfect !
Thanks a lot for your help.
Have a nice day,
Pascal.
Excellent! I’m glad this works. But we should fix KML support to support transparency if we can. Can you open a feature request at GitHub - OpenDroneMap/ODM: A command line toolkit to generate maps, point clouds, 3D models and DEMs from drone, balloon or kite images. 📷?
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Hi,
I just made the request.
Thanks
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