Polygons and tissot across the edge in Mollweide:

There seems to be a known problem with tissot and Polygon in the 'Mollweide' projection with basemap when these objects cross the 'limb' (180 degree line if the central longitude is 0. which is both the East and West edges of the map). The obvious solution is of course to split this into two polygons split at the limb. I realized that this was actually already available in examples (for tissots):
https://github.com/matplotlib/basemap/blob/master/examples/allskymap.py
and am wondering if there are plans to eventually replace Basemap.tissot or if there are deeper problems with this.

首先处理 Mollweide 投影的 Basemap.tissot 和 Polygon，然后对比 examples/allskymap.py 中现有的 tissot 相关方法。重现对象跨越边界的情况，并确定预期行为；除了解决跨越边界的问题之外，该 issue 没有定义具体的验收条件。