add_cyclic

cfplot.add_cyclic(field, lons)

add_cyclic is a wrapper for cartopy_util.add_cyclic_point(field, lons)

This is needed for the case of when the longitudes are not evenly spaced

due to numpy rounding which causes an error from the cartopy wrapping routine.

In this case the longitudes are promoted to 64 bit and then rounded

to an appropriate number of decimal places before passing to the cartopy

add_cyclic routine.