Description
Hello! I'm plotting day/night shading on a Robinson projection centered at -180 degrees with nightshade(), and as you can see, the shading doesn't look right. I'm also getting a warning about a non-monotonically increasing x coordinate. Presumably, nightshade() is plotting a transparent contour under the hood, but I couldn't see a way to change the starting longitude in the documentation. I'm not familiar enough with Basemap to know if this is a bug or if I'm missing something. Any suggestions would be greatly appreciated!
Plot
Warning
WARNING: x coordinate not montonically increasing - contour plot may not be what you expect. If it looks odd, your can either adjust the map projection region to be consistent with your data, or (if your data is on a global lat/lon grid) use the shiftgrid function to adjust the data to be consistent with the map projection region (see examples/contour_demo.py).
Code for reproduction
from mpl_toolkits.basemap import Basemap
import numpy as np
import matplotlib.pyplot as plt
from datetime import datetime
# lon_0 is central longitude of projection.
# resolution = 'c' means use crude resolution coastlines.
m = Basemap(projection='robin',lon_0=-180,resolution='c')
m.drawcoastlines()
m.fillcontinents(color='coral',lake_color='aqua')
# draw parallels and meridians.
m.drawparallels(np.arange(-90.,120.,30.))
m.drawmeridians(np.arange(0.,360.,60.))
m.drawmapboundary(fill_color='aqua')
date = datetime(2024,10,10,6)
m.nightshade(date,alpha=0.2)
plt.title("Robinson Projection")
plt.savefig('test.png')Environment
Ubuntu and RHEL
Python 3.8.13
Please let me know if I should be providing more details