xtick labels not respecting central_longitude for PlateCarree()

[erikvansebille]

Description

The xlabels in the PlateCarree (and potentially other projections) don't respect the central_longitude. In the example code below, the central longitude is correctly set to 160E. The xlabel at that longitude, however, is 0.

I've seen the same issue in #204, but there is was first reported fixed and then a patch was proposed. That does not seem to be included in version 0.16.0?

Code to reproduce

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

proj = ccrs.PlateCarree(central_longitude=160)
ax = plt.subplot(111, projection=proj)
gl = ax.gridlines(crs=proj)
gl.xlabels_bottom, gl.ylabels_left = (True, True)
ax.coastlines()
plt.show()

Full environment definition

Operating system

macOS with Python 2.7.15

Cartopy version

0.16.0

conda list

pip list

[QuLogic]

You should not pass crs=proj when calling ax.gridlines, because in that projection, 0 is at 160E. So in fact, it is respecting the central longitude and placing 0 where you tell it to place it. If you pass nothing, you get a 0 tick in the expected location.