"quiver" and other vector plots

Hi folks, I frequently need to make a vector plot that

    > shows (dx,dy) displacements from a set of (x,y)
    > points. "Quiver" doesn't seem to do quite what I want,
    > although maybe I just can't figure out how to use it.

There have been a few gripes about quiver...you are not alone.

    for i in range(len(x)):
                     label='shifts [* %4.1f]'%scale)

In general, repeated calls to plot can be very inefficient since a new
matplotlib.lines.Line2D object is created each time. In cases like
these, you want to use a LineCollection or a PolygonCollection (see
matplotlib.collections). There are a number of examples in
matplotlib.axes and matplotlib.finance. Search for collections...