plotparallels()/plotmeridians() only support xoffset or yoffset not both and do not support horizontalalignment or verticalalignment

plotparallels() and plotmeridians() only support xoffset or yoffset not both.

plotparallels() and plotmeridians() do not support horizontalalignment or verticalalignment via kwargs as these are hard coded within Basemap.

I found both of these because I wanted the labels inside the map border with the parallels above the line at the right of the plot and the meridians to the right of the line at the bottom of the plot. I found a hack by altering the returned matplotlib objects:

meridians = bmap.drawmeridians(meridians,labels=[0,0,1,0],fontsize=10,
                               color='gray', yoffset=-abs(right-left)
for k, v in meridians.iteritems():
    v[1][0].set_horizontalalignment('left')

This sets the label to the top but then moving them the size of the plot then setting horizontal alignment via returned matplotlib object.

定位 plotparallels() 和 plotmeridians() 的实现，并追踪 xoffset、yoffset 和 kwargs 的处理方式。验证地图两侧都有标签时的行为：两个偏移量应能同时生效，并且应接受 horizontalalignment 和 verticalalignment。完成的标准是，调用方不再需要修改返回的 matplotlib 对象来实现这种定位。