Eric,

I just hit a problem with using quiver with Basemap when when

angles='xy'. Because Basemap's x,y units are in meters, you end up

with angles that are quantized due to floating point truncation

(30000. + 0.001*u = 30000.). Changing to angles='uv' fixes the

problem, but it probably should be automatically scaled, as noted in

the comments:

elif self.angles == 'xy' or self.scale_units == 'xy':

# We could refine this by calculating eps based on

# the magnitude of U, V relative to that of X, Y,

# to ensure we are always making small shifts in X, Y.

I managed to fix the problem locally by setting:

angles, lengths = self._angles_lengths(U, V, eps=0.0001 *

self.XY.max())

but I'm not sure if you would want a different fix. If you're happy

with this fix, I'll go ahead an check in.

Ryan

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Ryan May

Graduate Research Assistant

School of Meteorology

University of Oklahoma