"""
Fix for bad longitudes in the reanalysis Med grib files

This routine uses the pygrib module, available here
https://github.com/jswhit/pygrib

"""
import pygrib3
import numpy as np
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt

# open the grib file and pick off the second record
# (the values for the first record are all zeroes)
gribs=pygrib.open('multi_reanal.med_10m.hs.197901.grb2')
grb=gribs[2]
data=grb.values

# extract the grib lat/lon values
lat, lon = grb.latlons()

# get some of the grib settings.  The last grib longitude is ok
lonmax=grb['longitudeOfLastGridPointInDegrees']
delta=grb['jDirectionIncrementInDegrees']

# build a new lon vector from the endpoint and delta increment
lon2=np.arange(lonmax-delta*lon.shape[1],lonmax,delta)

# pull a lat vector from the 2-d field
lat2=lat[:,0]

# now plot up some data on a map.  This will create a PNG file 
# called med_map.png in your local directory.

fig=plt.figure()
m=Basemap(projection='mill',resolution='l',
		llcrnrlon=lon2.min(), urcrnrlon=lon2.max(), 
                llcrnrlat=lat2.min(),urcrnrlat=lat2.max())
x,y=m(*np.meshgrid(lon2,lat2))
m.pcolormesh(x,y,data,shading='flat')
m.drawcoastlines()
m.fillcontinents()
m.drawparallels(np.arange(-90,91,5),labels=[1,0,0,0])
m.drawmeridians(np.arange(-180,180,15),labels=[0,0,0,1])
m.colorbar()
plt.title(grb.parameterName)
plt.savefig('med_map.png')