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I am trying to animate the movement of a polygon and thought a sound
approach would be to in a loop where I redraw after altering the offsets
value.  However I seem to not be able to scale the polygon correctly.
Here is an example of only trying to place a polygon (square) at 1,1.
You can see the translation is correct, but the scaling is wrong--the
polygon is only about a pixel high & wide.
Dave

------------------------------------------------------------------------
----------
import pylab as P
from matplotlib import collections, axes, transforms
import matplotlib.numerix as N

fig =3D P.figure()
a =3D fig.add_subplot(1,1,1)

verts =3D N.array([[0,0],[1,0],[1,1],[0,1]])
offsets =3D [[1,1]]
col =3D collections.PolyCollection([verts], offsets=3Doffsets,
                                transOffset=3Da.transData)
a.add_collection(col)
trans =3D
transforms.scale_transform(transforms.Value(1),transforms.Value(1))
col.set_transform(trans)=20
a.set_xlim([-5,5])
a.set_ylim([-5,5])
P.show()

------------------------------------------------------------------------
----------

Martinho MA wrote:
> Hello,
> I have a contour with a clim smaller than the limits of my data... and 
> because of this there is an error when I try to add a colorbar.
> Can someone help?
> Thanks
> MMA

I think the basic problem is that you are trying to use a colorbar as a 
legend in a case where it doesn't really makes sense; the colorbar is 
mapping a range of values to a range of colors, and you have values that 
are outside that range.  There are a couple ways to fix the problem:

1) Try using "colorbar(extend='both')".  This is a workaround, but it 
may do what you want.

2) Explicitly specify a list of contour levels that are within the range 
of your clim.  This is a better solution.

Eric

> 
> eg:
> 
> x=arange(20)
> y=arange(30)
> x,y=meshgrid(x,y)
> v=sqrt(x+y)  # max=6.928, min=0.0
> 
> # next is ok
> figure()
> contour(x,y,v)
> clim(0,7)
> colorbar()
> 
> # next gives the error: "ValueError: levels are outside colorbar range"
> figure()
> contour(x,y,v)
> clim(2,6)
> colorbar()
> 
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