[Matplotlib-users] basemap imshow() extents

[Scott H. <st...@co...>]

I'm having trouble with transform_scalar() and imshow() with basemap. 
Essential I have data from satellite tracks that are either smaller or 
larger than the map extent, so I don't want to use Basemap.imshow() 
which sets the 'extent' keyword automatically.

I tried following the following suggestion, but I can't get things to 
line up..
http://comments.gmane.org/gmane.comp.python.matplotlib.general/25085

I suspect I've done something wrong in the code below?:


# -------------------------------
from mpl_toolkits.basemap import Basemap
import matplotlib.pyplot as plt

LL = (-68, -26)
UR = (-66, -21)
bmap = Basemap(projection='merc',
                llcrnrlat=LL[1],
                urcrnrlat=UR[1],
                llcrnrlon=LL[0],
                urcrnrlon=UR[0],
                resolution='i',
                suppress_ticks=False,
                ax=ax)
bmap.drawcountries(linewidth=1)

# Overlay image with extents that don't match map boundaries
nLon, nLat = image.shape
LL = (-69.915, -31.161)
UR = (-65.075, -17.334)
dy = -0.006666664
lats = UR[1] + dy * np.arange(nLat)
extent = (LL[0], UR[0], LL[1], UR[1])
nx = nLon; ny = nLat
image_xy = bmap.transform_scalar(image, lons, lats[::-1], nx, ny)
x, y = bmap(extent[:2],extent[2:])
extent_xy = (x[0], x[1], y[0], y[1])
im = plt.imshow(image_xy, extent=extent_xy)



-- 
---------------
Scott T. Henderson
http://www.geo.cornell.edu/eas/gstudent/sth54/contact.html