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I'm working with a map data in the NetCDF format in QGIS but can't find a way to align it with a vector polygon.

Map sources:

I tried various project CRS as well as projecting both the vector and the raster layer – without any success. the layers are out of proportion and in the wrong place.

My result:

enter image description here

How it should be positioned:

enter image description here

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    This is probably the most frequently asked question on this site. What (if any) are the original CRSs of both datasets and exactly what did you do (which tool/menu, what parameters)
    – user2856
    Apr 21, 2022 at 9:31
  • the original CRS for the countries dataset is WGS84 – EPSG:4326, for the netCDF raster no information is provided. i tried multiple approaches, on my most recent try i set the project CRS to WGS84 to match the countries dataset, i simply dropped the countries dataset as well as the netCDF dataset. now the netCDF dataset isn't visible at all. warping it to WGS84 didn't help either. i'm thinking that maybe the netCDF doesn't contain a proper CRS at all.
    – fkid
    Apr 21, 2022 at 10:03
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    Any time you "assign" a coordinate system there is a high probability of doing it incorrectly. That probability increases if the data format is unfamiliar, and approaches certainty if you need to change more than one layer.
    – Vince
    Apr 21, 2022 at 12:09
  • I'm not sure in which direction you're trying to point me. Not assigning a CRS didn't give me a better result.
    – fkid
    Apr 21, 2022 at 13:59
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    NetCDF is using a CRS that uses metres as units not decimal degrees, so it's definitely not EPSG:4326.
    – nmtoken
    Apr 21, 2022 at 15:16

1 Answer 1

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Using gdalinfo we can find the actual coordinate reference system of the NetCDF file:

gdalinfo alpcyc.1km.epic.pp.ex.1ka.nc -sd HDF5:"alpcyc.1km.epic.pp.ex.1ka.nc"://topg

Shows us the projection is (proj4):

proj4=+units=m +proj=utm +no_defs +zone=32 +a=6378137 +rf=298.257223563 +towgs84=0.000,0.000,0.000 +to_meter=1

In QGIS selecting WGS 84 UTM 32 N (EPSG:32632) gives us alignment:

NetCDF in correct projection

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  • Worked like a charm! Thanks for pointing out how to find the projection of the NetCDF.
    – fkid
    Apr 22, 2022 at 5:41
  • why doesn't q pick that up on import? you shouldn't need to assign it, perhaps it's using an older version of gdal than you cmd app? edit: oh it's just listed in the meta in that weird nc way, not picked up by gdal formally ... all good 👌
    – mdsumner
    Apr 23, 2022 at 22:53

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