DOC: show integration with Cartopy

[andyrich]

When a contextily basemap is added to an axis projected with cartopy, the map appears upside down.

https://stackoverflow.com/questions/61737584/contextily-map-upside-down-when-used-with-cartopy

[jorisvandenbossche]

@andyrich I answered on StackOverflow: for me this seems to be working fine.

What version of contextily are you using?

[andyrich]

it looks like cartopy needs to be version 0.18

[jorisvandenbossche]

Ah, thanks.

I noticed this in their 0.18 changelog:

The default value for the origin argument to :func:cartopy.mpl.geoaxes.GeoAxes.imshow is now 'upper' to match the default in Matplotlib.

which I suppose might be the reason it is fixed now.

[jorisvandenbossche]

I think it would be nice to have a page in the documentation showing the use of cartopy and contextily together (and thus a page can then also mention you need cartopy >= 0.18).

So reopening the issue as documentation issue.