Map plotting uses cartopy land/ocean mask

[adele-morrison]

Many of the Documented Examples use something like:

import cartopy.feature as feature
land_50m = feature.NaturalEarthFeature('physical', 'land', '50m',
                                        edgecolor='black',
                                        facecolor='gray',
                                        linewidth=0.2)
...
ax.add_feature(land_50m, zorder=2)

This means that the plots are using the cartopy land/ocean mask and not the model land/ocean mask. I find this quite misleading, because in some areas the masks are very different (e.g. Ross and Weddell Seas). I think that we should use the model mask instead.

What do others think? Was there a reason behind choosing to use the cartopy land mask?

[adele-morrison]

We had a discussion in Canberra on this, and agreed to:

1. Change the default land mask to use the model land mask not the cartopy mask in all Documented Examples. There is an example of how to use the model land mask in Cross-slope_section.ipynb. Notebooks that need fixing:

   • Age_at_the_Bottom.ipynb
   • Barotropic_Streamfunction.ipynb
   • Compare_SST_SSS_TemperatureSalinity_to_WOA13.ipynb
   • Decomposing_kinetic_energy_into_mean_and_transient.ipynb
   • Model_Resolution_Comparison.ipynb
   • SeaIceSeasonality_DFA.ipynb

2. Edit the Making_Maps_with_Cartopy tutorial to provide methods for plotting both cartopy and model land masks.