Closed line is wrapping around the border

[pelson]

Description

When adding a line that is closed (starts and ends at the same location), it will be interpreted as a polygon, and therefore get the border of the map in the resulting geometry/line.

Code to reproduce

import matplotlib.pyplot as plt
import cartopy.crs as ccrs

plt.figure()
ax = plt.axes(projection=ccrs.PlateCarree())

ax.coastlines()

lons = [0, 170, -170, 0]
lats = [10, 20, 30, 10]

ax.stock_img()
ax.plot(lons, lats, '--', color='orange', linewidth=4, transform=ccrs.Geodetic())
plt.show()

Cartopy version

v0.16

[pelson]

This could be quite a tricky one, and is pretty much a duplicate of #158.
It suggest the correct solution might be to ensure that matplotlib is producing the appropriate Path codes in all cases (or enforcing that on the GeoAxes).

[pelson]

Wowzers. Thanks for fixing this @QuLogic!