# Needed modules
import xarray as xr
import cftime, matplotlib.pyplot as plt
from matplotlib.dates import DateFormatter, YearLocator
import nc_time_axis

# Open data on ESGF server
d_tas = xr.open_dataset ("https://vesg.ipsl.upmc.fr/thredds/dodsC/cmip5/output1/IPSL/IPSL-CM5A-LR/rcp85/day/atmos/day/r1i1p1/v20111103/tas/tas_day_IPSL-CM5A-LR_rcp85_r1i1p1_20060101-22051231.nc", decode_times=True, use_cftime=True)

# Define variable
tas = d_tas['tas'][0:800,34,45].squeeze()

# A few checks
print ( tas.time.values[0] )
print ( tas.time.attrs )

# Plots
fig, axs = plt.subplots (nrows=2, ncols=2, figsize=(10,10) )
axs=axs.ravel()

## Very simple plot
ax = axs[0]
ax.plot ( tas.time, tas )
ax.set_title ( 'Correct plot \nCorrect time axis')

## Add formatting : \!/ Time axis is shifted
ax = axs[1]
ax.plot ( tas.time, tas )
ax.xaxis.set_major_formatter ( DateFormatter ('%Y-%M'))
ax.set_title ( 'Bug using DateFormatter \nTime axis is shifted by about 30 years')

## Solution using nc_time_axis
ax = axs[2]
ax.plot ( tas.time, tas )
formatter = nc_time_axis.CFTimeFormatter ("%Y-%m", "noleap")
ax.xaxis.set_major_formatter ( formatter )
ax.set_title ( 'Solution using nc_time_axis')

plt.savefig ('BugMplCftime.png')