basemap / matplotlib edge case artifacts

[Reimar Bauer]

In the polar region the current used basemap / matplotlib creates data artifacts which become on a more detailed zoom level cleared.

[Reimar Bauer]

We need a small data example to push this issue to the matplotlib/basemap library, and try to solve it for us.

[Reimar Bauer]

jswhit is no longer the maintainer of basemap, and it isn't a rumor that he recommends using cartopy for new developments/projects. Jeff has handed the reins for basemap over to me with the understanding that I plan on taking the project on its death march. I will make sure that it works for the most recent versions of its dependencies; I may even make incremental improvements here and there. I will also review and accept any PR with new features and bugfixes for the next few years.

https://github.com/matplotlib/basemap/issues/267

https://github.com/SciTools/cartopy/issues/920

[Reimar Bauer]

this likly is solved by ca9616c reopen if we missed something