"""

This example code illustrates how to access and visualize a GPM L2 HDF5 file 
in Python.

If you have any questions, suggestions, or comments on this example, please use
the HDF-EOS Forum (http://hdfeos.org/forums).  If you would like to see an
example of any other NASA HDF/HDF-EOS data product that is not listed in the
HDF-EOS Comprehensive Examples page (http://hdfeos.org/zoo), feel free to
contact us at eoshelp@hdfgroup.org or post it at the HDF-EOS Forum
(http://hdfeos.org/forums).

Usage:  save this script and run

    python 2A.GPM.DPR.V7-20170308.20170704-S001905-E015140.019017.V05A.HDF5.py

The HDF file must be in your current working directory.

Tested under: Python 2.7.13 :: Anaconda 4.3.22 
Last updated: 2017-09-11

"""

import os

import h5py
import matplotlib as mpl
import matplotlib.pyplot as plt
from mpl_toolkits.basemap import Basemap
import numpy as np

# Reduce font size because file name is long.
mpl.rcParams.update({'font.size': 8})


file_name = '2A.GPM.DPR.V7-20170308.20170704-S001905-E015140.019017.V05A.HDF5'

with h5py.File(file_name, mode='r') as f:
    
    name = '/NS/SLV/precipRateESurface'
    data = f[name][:]
    units = f[name].attrs['units']
    _FillValue = f[name].attrs['_FillValue']
    data[data == _FillValue] = np.nan
    data = np.ma.masked_where(np.isnan(data), data)
        
    # Get the geolocation data.
    latitude = f['/NS/Latitude'][:]
    longitude = f['/NS/Longitude'][:]

        
    m = Basemap(projection='cyl', resolution='l',
                llcrnrlat=-90, urcrnrlat=90,
                llcrnrlon=-180, urcrnrlon=180)
    m.drawcoastlines(linewidth=0.5)
    m.drawparallels(np.arange(-90, 91, 45))
    m.drawmeridians(np.arange(-180, 180, 45), labels=[True,False,False,True])
    m.scatter(longitude, latitude, c=data, s=1, cmap=plt.cm.jet,
              edgecolors=None, linewidth=0)
    cb = m.colorbar(location="bottom", pad='10%')    
    cb.set_label(units)

    basename = os.path.basename(file_name)
    plt.title('{0}\n{1}'.format(basename, name))
    fig = plt.gcf()
    # plt.show()
    pngfile = "{0}.py.png".format(basename)
    fig.savefig(pngfile)