Re: [Matplotlib-users] A question on Basemap projection

[Jeff W. <js...@fa...>]

Mauro Cavalcanti wrote:
> Dear Jeff,
>
> 2008/12/7 Jeff Whitaker <js...@fa...>:
>   
>> Mauro:  Just set the llrncrlat,urcrnrlon appropriately.  For instance,
>> llcrnrlon=0, urcrnrlon=360 will produce a map centered on the dateline while
>> llcrnrlon=-180, urcrnrlon=180 will produce a map centered on Greenwich.
>>     
>
> Thanks! I had not figured out that the decimal coordinates used by
> Basemap range from 0 to 360 (and not just from -180 to 180). Using
> this tip, I could also create a map centered on the Indian Ocean. BTW,
> by varying the llcrnrlat and urcrnrlat, can one also create maps
> centered on the North and South poles using a Equirectangular
> projection?
>   

Mauro:  I realized that this is actually possible with the Cassini 
projection (the transverse aspect of the cylindrical equidistant).

from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt
width=20000000
m = Basemap(lon_0=0,lat_0=0,projection='cass',\
            width=0.75*width,height=2*width)
m.drawcoastlines()
m.fillcontinents(color='coral',lake_color='aqua')
m.drawparallels(range(-80,81,21))
m.drawmeridians(range(-180,181,60))
m.drawmapboundary(fill_color='aqua')
plt.show()

Don't know why you would actually do it though, if you want to show 
polar regions you should probably use the polar stereographic maps 
(npstere, spstere).


-Jeff
> With best regards,
>
>   


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Jeffrey S. Whitaker         Phone : (303)497-6313
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