pip install cartopy fails due to compilation error

[mrechte]

Hello,
cartopy is missing in the project's requirements.txt.
Trying to install manually in the virtualenv gives the following error:

  gcc -pthread -Wno-unused-result -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -march=x86-64 -mtune=generic -O3 -pipe -fno-plt -fno-semantic-interposition -march=x86-64 -mtune=generic -O3 -pipe -fno-plt -march=x86-64 -mtune=generic -O3 -pipe -fno-plt -fPIC -I/usr/include -I./lib/cartopy -I/usr/include -I/usr/include/python3.8 -c lib/cartopy/trace.cpp -o build/temp.linux-x86_64-3.8/lib/cartopy/trace.o
  Dans le fichier inclus depuis lib/cartopy/trace.cpp:612:
  /usr/include/proj_api.h:37:2: erreur: #error 'To use the proj_api.h you must define the macro ACCEPT_USE_OF_DEPRECATED_PROJ_API_H'
     37 | #error 'To use the proj_api.h you must define the macro ACCEPT_USE_OF_DEPRECATED_PROJ_API_H'
        |  ^~~~~
  Dans le fichier inclus depuis lib/cartopy/_trace.h:27,
                   depuis lib/cartopy/trace.cpp:613:
  /usr/include/proj_api.h:37:2: erreur: #error 'To use the proj_api.h you must define the macro ACCEPT_USE_OF_DEPRECATED_PROJ_API_H'
     37 | #error 'To use the proj_api.h you must define the macro ACCEPT_USE_OF_DEPRECATED_PROJ_API_H'
        |  ^~~~~
  error: command 'gcc' failed with exit status 1

Thanks

[mrechte]

It seems cartopy uses a deprecated API:

# The 0.17.0 release doesn't build against recent releases of PROJ due to
# API deprecations. This is a temporary hack so at least it compiles
# against the deprecated API. Hopefully someday this won't be necessary....
# See also https://github.com/SciTools/cartopy/pull/1289
sed -i '/# Main setup/iextra_extension_args["define_macros"] = [("ACCEPT_USE_OF_DEPRECATED_PROJ_API_H", None)]\n' setup.py

As I install with pip, I do not know how to apply this patch.

[larvorg]

I strongly recommend installation using conda (not necessarily a full Anaconda install) as it will bring in all of the executable dependencies that cartopy requires. With conda installed, installing the latest version of cartopy would look like:

conda install --channel conda-forge cartopy

[larvorg]

Experience of someone on stackoverflow (https://stackoverflow.com/questions/53697814/using-pip-install-to-install-cartopy-but-missing-proj-version-at-least-4-9-0) :

Unfortunately installation of binaries for Python is notoriously fiendish on Windows (partly because the toolchain changes with each Python version [at least, it used to until >= python 3.5], and partly because most of the developers of the scientific python ecosystem typically don't use or have access to Windows machines). Christoph Gohlke's incredible resource that you have already been using is the major exception to this statement.

I personally have spent several man-weeks getting cartopy installed on Windows (with significant help from folks including the Enthought team and Christoph Gohlke) - I poured all of this knowledge into the conda-forge packaging ecosystem so that others don't have to feel that pain if they choose to use conda.

If you really, really, really must install cartopy manually on your Windows machine, you might like to take a look at https://github.com/conda-forge/cartopy-feedstock/tree/master/recipe which contains all of the steps that were required to build cartopy in Windows. In addition to this, all of its dependencies are documented in similarly named repositories on the conda-forge organisation.

Finally, given your output and @cgohlke's suggestion - try installing his Shapely binary https://www.lfd.uci.edu/~gohlke/pythonlibs/#shapely.