cartopy version

[avaldebe]

Currently we can not use cartopy 0.20 on CI as it requires Proj 8+ and Ubuntu 20.04LTS only provides 6.3.1.

In order to pip install "cartopy>=0.20", one would need to

• update to the next LTS (Ubuntu 22.04), which will pack Proj 8.2.1
• build Proj from source

None of these options are reasonable for CI, not to users installing from pip (conda users are not affected).

Also, Iris 3.2 requires cartopy >=0.20

[avaldebe]

as far as I can tell we use cartopy on

• pyaerocom.region:Region.plot
• pyaerocom.aeroval.modelmaps_helpers:calc_contour_json
• pyaerocom.plot.helpers:projection_from_str
• pyaerocom.plot.mapping:set_map_ticks
• pyaerocom.plot.mapping:init_map
• pyaerocom.plot.mapping:plot_griddeddata_on_map
• pyaerocom.plot.mapping:plot_nmb_map_colocateddata
• pyaerocom.plot.plotcoordinates:plot_coordinates

[jgriesfeller]

Shouldn't it be possible to build proj8 and put the resulting libraries and support files into a tar file that CI then installs during setup of the CI VMs?
Untaring e.g. to ${HOME}/lib and adding the path to $LD_LIBRARY_PATH should be enough for that.

[avaldebe]

it would be "easier" to use a custom docker container, but we would not be testing against the environment of a pip user

[avaldebe]

Cartopy version 0.19.* does no longer install on CI, e.g. here and here

The problem is that cartopy setup script imports convert_path from setuptools

from setuptools import Command, Extension, convert_path, setup

but convert_path is not provided by setuptools.

Up to version 60.9.3, setuptools imports convert_path from distutils.util.

from distutils.util import convert_path

Now, as distutils was deprecated on Python 3.10 and will be removed on Python 3.12 (see PEP 632),
setuptools cleaned up the dependency on 60.10.0 which was released on March 16th...

[jgriesfeller]

I had a look at the cartopy github pages. In the current master this problem has been solved (commit from Friday):
https://github.com/SciTools/cartopy/blob/c9be040cdc015f15289433a3cd7bcd049bb57a9f/setup.py#L34

Not sure when they will release the next time though.

[avaldebe]

This would affect the next version 0.20.*, which needs Proj 8+.
On CI we need version 0.19.*, which uses needs Proj 4.9+.

In any case, I can open an issue asking for a back-port of the fix and a new 0.19.0.post2 release.

[magnusuMET]

0.19 series is not forwards compatible either, and the pinning in setup.cfg means I can not install on rhel8. Is there a way to pin cartopy==0.19 in CI and removing it from setup.cfg?

[avaldebe]

tried different things, but the only reliable way was to move cartopy/iris to extras, PR #620