quiver arrows reverse in all polar projections except orthographic. Why?

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Assessment

Difficulty
4/5
Estimated time
3-5 days
Newbie friendliness
35/100
Issue type
Bug
Clarity
Mostly clear
Activity status
Stale
Tech stack
python
Domain
data-visualization

Research direction

Start by running the linked plot_quiver_bug_test.py script and comparing the orthographic, polar stereographic, Lambert azimuthal, and azimuthal equidistant results for the Southern Ocean. Trace how quiver vectors are transformed by each projection; done means eastward vectors remain correctly oriented in the polar projections as they do in orthographic projection.

Written by the indexing model from the issue text.

Description

Hi

I'm trying to plot vectors in the Southern ocean using basemap and matplotlib.
To illustrate my problem I've created a zonal jet at 60S.
I have U and V as 2D arrays and lon and lat as 1D arrays, all with cyclic point added and lon is from -180 to 180.
If I plot in orthographic projection the vectors correctly shows eastward motion, but if I use any of the polar projections (spstere, splaea spaeqd) the vectors reverse!
This is really strange and oddly enough it does not seem to happen if I make the same plot over the North Pole.

I've noted that in the southern hemisphere lon_0 has a different meaning for orthographic projection than for spstere, splaea etc.
So to orient the maps the same way I must pass lon_0=0 in orthographic projection and lon_0=180 in polar stereographic projection if I plot southern hemisphere.
But this is not the case in the Northern hemisphere.
Could this be part of the problem?

Here's the script that creates the results:
https://dl.dropboxusercontent.com/u/86754720/plot_quiver_bug_test.py
Here's the contourf of u and v
https://dl.dropboxusercontent.com/u/86754720/velocity_bug_contourf.png
and here are the vectors
https://dl.dropboxusercontent.com/u/86754720/velocity_bug_quiver.png

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