Cartopy incompatibility with new matplotlib 3.3.0

[bradyrx]

Description

It looks like there's an incompatibility between cartopy 0.17.0 and the new matplotlib 3.3.0. See the bottom of https://travis-ci.com/github/bradyrx/climpred/builds/176836907.

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-3-9e314160e532> in <module>

      1 ax = plt.axes(projection=ccrs.Orthographic(-80, 0))

      2 p = ax.pcolormesh(recon.TLONG, recon.TLAT, recon.mean('time'), 

----> 3               transform=ccrs.PlateCarree(), cmap='twilight')

      4 ax.add_feature(cfeature.LAND, color='#d3d3d3')

      5 ax.set_global()

~/miniconda/envs/climpred-dev/lib/python3.6/site-packages/cartopy/mpl/geoaxes.py in pcolormesh(self, *args, **kwargs)

   1457                              ' consider using PlateCarree/RotatedPole.')

   1458         kwargs.setdefault('transform', t)

-> 1459         result = self._pcolormesh_patched(*args, **kwargs)

   1460         self.autoscale_view()

   1461         return result

~/miniconda/envs/climpred-dev/lib/python3.6/site-packages/cartopy/mpl/geoaxes.py in _pcolormesh_patched(self, *args, **kwargs)

   1489         allmatch = (shading == 'gouraud')

   1490 

-> 1491         X, Y, C = self._pcolorargs('pcolormesh', *args, allmatch=allmatch)

   1492         Ny, Nx = X.shape

   1493 

TypeError: _pcolorargs() got an unexpected keyword argument 'allmatch'

TypeError: _pcolorargs() got an unexpected keyword argument 'allmatch'

It looks like cartopy is using the keyword allmatch which must have been dropped, although it's not mentioned in the changelog for matplotlib. We fixed this issue by forcing matplotlib <= 3.2.2 in our docs for now.

[greglucas]

Yes, Cartopy is using some private functions from MPL in the pcolormesh function, so that change wasn't announced in the MPL release. The fix is in Cartopy 0.18, so try to upgrade if you can. This is the commit.

[QuLogic]

Closing as fixed in 0.18.0; there's nothing we can do about 0.17.0.