import vcs, MV2, cdms2, cdutil

# Open sample file
f = cdms2.open('clt.nc')
d = f('clt',time=slice(0,1))

# Get anomaly field to have negative values
d_anom = MV2.subtract(d, cdutil.averager(d,axis='xy'))
d_anom.setAxis(0,d.getAxis(0))
d_anom.setAxis(1,d.getAxis(1))
d_anom.setAxis(2,d.getAxis(2))

# Plot
x = vcs.init()
iso = vcs.createisofill()

#iso.levels = [-40, -30, -20, -10, 0, 10, 20, 30, 40]
iso.levels = [-40, -30, -20, -10, 10, 20, 30, 40]  #### This does not work
iso.levels.insert(0,-1.e20)
iso.levels.append(1.e20)

iso.colormap = 'bl_to_darkred'
colors = vcs.getcolors(iso.levels,colors=range(16,240))
#colors = vcs.getcolors(iso.levels,colors=range(16,240),split=0)
iso.fillareacolors = colors

x.plot(d_anom, iso)

x.png('test.png')