question:
“how I can identify the correct CRS projection for a orthofoto producd in ODM?”
explanation
I have issues using the correct projetions for the “odm_orthophoto.tif”.
Importing the georerefenced files in q-gis, it will assign automatically the coordinate refrence system “wgs 84 / utm zone 33N” and not the standard “EPSG:4326 - wgs 84”. The othofoto is thus not perfectly aligned to other layers.
If I assign manually the latter CRS to the layer it will be completly out of any alignment.
An inspection to quality report did not help me finding the correct information.
thank you !
Daniele
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ODM will assign the most correct local UTM CRS, which in the case of your data is apparently EPSG:32633.
Any misalignments are likely down to the datasources themselves, not the projection.
For instance, if you’re comparing data to a basemap like Google Earth, that will be anywhere from 3-10m off typically.
Also, if your data has not been verified with GCPs, it can also have distortions and shifts that may make it not align how one expects.
And yes, forcing a different projection will expectedly break things as the coordinates will not be correct. If you absolutely need something in EPSG:4326 (which is a really bad idea 99% of the time for a ton of reasons), you need to properly reproject the data, either by specifying the CRS for export in WebODM from the Map View, or by using the QGIS Toolbox.
Here’s some further reading:
StephaneP’s Diary | You thought OpenStreetMap data uses the WGS84 datum? No it doesn’t! | OpenStreetMap
Show a warning when CRSes based on a datum ensemble are selected by nyalldawson · Pull Request #43088 · qgis/QGIS (github.com)
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thank you a lot, very clear and helping!
I’ll try some workaround (i.e manually moving raster) that suits to my needs.
The solution with GPC may be handy in the future.
About this possibility,
I’m not sure where to find it in my interface, and I dont see it in th command line interface.
Daniele
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Not sure if in topic, but I’d like to point out that in nearby spot (1 kilometer) things works differently.
Indeed, with the same settings in odm and trying to match woth th SAME wms layer (landregister in italy) in the two spots in one I get a perfect match in the other not.
See enclosed screenshot.
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If you’re using WebODM v1.9.11 it will be there.
Check the post with release notes here for how to do it:
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