Unable to plot using Vincent,

问题

Slightly related to: Unable plot with vincent in IPython, yet none of the suggested solutions work for me. I'm using an IPython Notebook, also the latest version.

I'm using python 3.4 and just installed the latest version of Vincent. When I try to plot the example in the documentation:

import json
import vincent
vincent.initialize_notebook()

world_topo = r'world-countries.topo.json'
geo_data = [{'name': 'countries',
         'url': world_topo,
         'feature': 'world-countries'}]

vis = vincent.Map(geo_data=geo_data, scale=200)
vis.display()

I don't get anything plotted.

来源：https://stackoverflow.com/questions/28480426/unable-to-plot-using-vincent