Polar Projection PDF Issue

まだ誰も着手していません。

Python 3.4
Conda 3.18.3
Matplotlib 1.5.1
basemap 1.0.7
Adobe Reader XI

Trying to plot a polar projection with a custom shapefile results in an error when opening the PDF in Adobe Reader.

I am creating two orthographic projections (a southern and northern hemisphere).

```
basemaps.append(Basemap(projection='ortho', lon_0=270, lat_0=90., resolution='c', ax=axes[0]))
basemaps.append(Basemap(projection='ortho', lon_0=90, lat_0=-90., resolution='c', ax=axes[1]))
```

I then draw a full world shapefile on each projection:

```
basemap.readshapefile('Earth', 'globe')
...
plt.savefig('amaps.pdf')
```

Everything works fine here and both basemaps display with the proper lines and shapes drawn. However, when downloading the PDF and displaying it in Adobe Acrobat, you will get something like this:
[amap.pdf](https://github.com/matplotlib/matplotlib/files/99791/amap.pdf) (which looks fine if you view it in your browser, but try downloading it and opening it with Adobe Reader). We've determined that the problem arises when the coastline includes lon, lat pairs in the opposite hemisphere from the hemisphere that it is to be drawn in. So if you are drawing the southern hemisphere, you cannot read a shapefile that has lon, lat points in the norther hemisphere, and vise-versa.

Our workaround required creating two separate shapefiles, one for the northern hemisphere and one for the southern. So now it looks like this:

```
# drawing northern hemisphere
if polar and idx == 0:
basemap.readshapefile('Earth_north', 'nh')
elif polar and idx == 1:
# drawing southern hemisphere
basemap.readshapefile('Earth_south', 'sh')
# drawing all other projections
else:
basemap.readshapefile('Earth', 'globe')
```

This works fine but shouldn't be necessary.

まず、提供された正射図法のスニペットとPDFを使用して、Basemap.readshapefileとplt.savefigで問題を再現します。半球をまたぐジオメトリについて、shapefileの処理とPDFの出力パスを調査します。PDFをAdobe Readerで開いたときに、全世界のshapefileが両方の半球で正しくレンダリングされれば完了です。

索引モデルが issue の本文から書いたものです。