pcolormesh can't shiftdata when X,Y are 1 larger than data

还没有人认领这个 Issue。

The pcolormesh docs (as noted in this issue https://github.com/matplotlib/basemap/issues/107) explain that:

"Ideally the dimensions of x and y should be one greater than those of data; if the dimensions are the same, then the last row and column of data will be ignored."

However when I actually try and use Basemap pcolormesh with this shape array, the shiftdata method sometimes fails because the data is not the same shape:

```
import numpy as np
from mpl_toolkits.basemap import Basemap
x = np.arange(-179, 191, 10)
y = np.array([50, 51, 52])
data = np.ones((2, 36))
xv, yv = np.meshgrid(x, y)
map = Basemap()
map.pcolormesh(xv, yv, data, latlon=True)
```

results in this error (in 1.0.7):

IndexError: Inconsistant shape between the condition and the input (got (3, 37) and (2, 36))

首先运行报告中的示例，并跟踪 Basemap.pcolormesh 到 shiftdata，即 issue 中提到的入口点。比较坐标形状 (3, 37) 与数据形状 (2, 36)；当这个文档中记录的 pcolormesh 形状不再引发报告的 IndexError 时，即表示完成。

由索引模型根据 Issue 内容生成。