llcrnrlon vs llcrnrx [-180, 180 vs 0, 360]

I was playing with the projections and it took me a while to understand what's going on... I need the 'rotpole' projection to convert some locations and plot some graphs. I have all the information: lon_0 = 10, o_lon_p = 10, o_lat_p = 10, but I don't have the real lat/lon, I have the rotated one so I'm forced to use llcrnrx, llcrnry....

I have a climate model that gives me the output in this rotated pole projection with rotated left lon = -19.5, rotated right lon = 21, rotated bottom lat = -25, rotated top lat = 20.5.

First take:

import mpl_toolkits.basemap as mb
kwargs = {
    'projection': 'rotpole',
    'llcrnrx': -19.5,
    'llcrnry': -25,
    'urcrnrx': 21,
    'urcrnry': 20.5,
    'o_lon_p': 10,
    'o_lat_p': 32.5,
    'lat_0': 10
}
m = mb.Basemap(**kwargs)

Now m.drawcoastlines() will give me a huge map that goes backwards on X axis... After a full day of investigation... I saw that m.llcrnrx' takes the value of360-19.5 = 340.5andm.urcrnrx = 21` so this clearly dosn't work...

Is this behaviour wanted? I mean, when building m = mb.Basemap(...) using llcrnrlon, llcrnrlat... you can safely pass negative values to llcrnrlon but when using llcrnrx you're forced to use (0, 360)...

Working version is:

import mpl_toolkits.basemap as mb
kwargs = {
    'projection': 'rotpole',
    'llcrnrx': 0,
    'llcrnry': -25,
    'urcrnrx': 21,
    'urcrnry': 40.5,
    'o_lon_p': 10,
    'o_lat_p': 32.5,
    'lat_0': -9.5
}
m = mb.Basemap(**kwargs)

So now I'm forced to do:

# x, y taken from climate model
xoffset = 19.5
lon, lat = m([x + xoffset], [y], inverse=True)

Even more confusing is the fact that you can use negative values in convert as in m(-1, 0, inverse=True) and you get the correct negative real longitude value...

Edit: using version 1.0.7; fixed 'urcrnry' misspell

Inizia riproducendo gli esempi forniti del costruttore Basemap e della conversione inversa con le coordinate del polo ruotato segnalate. Esamina come il punto di ingresso di Basemap gestisce gli intervalli llcrnrx e urcrnrx, quindi determina il comportamento previsto delle coordinate e aggiungi la copertura per il caso di longitudine ruotata negativa. L’attività è completata quando l’intervallo di coordinate documentato e l’orientamento risultante della mappa sono coerenti.