

In [2]:

    
%matplotlib inline
import netCDF4
import matplotlib.pyplot as plt
import matplotlib as mpl
from matplotlib import dates
import numpy as np

Read variables and units

We assume the data file is present in the following directory:



In [6]:

    
datafile = "~/CMEMS_INSTAC/INSITU_MED_NRT_OBSERVATIONS_013_035/history/mooring/IR_TS_MO_61198.nc"

We use the os mudule to extend the ~.



In [7]:

    
import os
datafile = os.path.expanduser(datafile)



In [8]:

    
with netCDF4.Dataset(datafile, 'r') as ds:
    time_values = ds.variables['TIME'][:]
    temperature_values = ds.variables['TEMP'][:]
    temperatureQC = ds.variables['TEMP_QC'][:]
    time_units = ds.variables['TIME'].units
    temperature_units = ds.variables['TEMP'].units
    time2 = netCDF4.num2date(time_values, time_units)

We also mask the temperature values that have quality flag not equal to 1.



In [58]:

    
temperature_values = np.ma.masked_where(temperatureQC != 1, temperature_values)

Basic plot

We create the most simple plot, without any additional option.



In [59]:

    
fig = plt.figure()
plt.plot(time2, temperature_values)
plt.ylabel(temperature_units)









    Out[59]:





<matplotlib.text.Text at 0x12e0ba90>

Main problems:

The figure is not large enough.
The labels are too small.

Improved plot

With some commands the previous plot can be improved:

The figure size is increased
The font size is set to 20 (pts)
The year labels are rotated 45º



In [65]:

    
mpl.rcParams.update({'font.size': 20})

fig = plt.figure(figsize=(15, 8))
ax = fig.add_subplot(111)
plt.plot(time2, temperature_values, linewidth=0.5)
plt.ylabel(temperature_units)
plt.xlabel('Year')
fig.autofmt_xdate()
plt.grid()

Final version

We want to add a title containing the coordinates of the station. Longitude and latitude are both stored as vectors, but we will only keep the mean position to be included in the title.

LaTeX syntax can be used, as in this example, with the degree symbol.



In [68]:

    
with netCDF4.Dataset(datafile, 'r') as ds:
    lon = ds.variables['LONGITUDE'][:]
    lat = ds.variables['LATITUDE'][:]
figure_title = r'Temperature evolution at \n%s$^\circ$E, %s$^\circ$N' % (lon.mean(), lat.mean())
print figure_title









    



Temperature evolution at 
-2.33189$^\circ$E, 36.5698$^\circ$N

The units for the temperature are also changed:



In [71]:

    
temperature_units2 = '($^{\circ}$C)'



In [75]:

    
fig = plt.figure(figsize=(15, 8))
ax = fig.add_subplot(111)
ax.xaxis.set_major_locator(dates.YearLocator(base=2))
ax.xaxis.set_minor_locator(dates.YearLocator())
plt.plot(time2, temperature_values, linewidth=0.5)
plt.ylabel(temperature_units2, rotation=0., horizontalalignment='right')
plt.title(figure_title)
plt.xlabel('Year')
fig.autofmt_xdate()
plt.grid()