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

Chưa có ai nhận issue này.

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

Bắt đầu bằng cách chạy script plot_quiver_bug_test.py được liên kết và so sánh các kết quả của orthographic, polar stereographic, Lambert azimuthal và azimuthal equidistant cho Southern Ocean. Theo dõi cách các vector quiver được biến đổi qua từng phép chiếu; hoàn thành khi các vector hướng đông vẫn giữ đúng hướng trong các phép chiếu cực như trong phép chiếu orthographic.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.