working with geojson and vincent on python?

Question

I want to import a geojson file into python so I can map it with a visualization package vincent and merge with other data in a pandas data frame.

To be specific, the said geojson file is: https://gist.githubusercontent.com/justgrimes/a63e8ec28868d8ce337e/raw/13cd7d8867e579d8b4f6b44f002a99940fba0504/DCNeighborhoodBoundariesWaPo.geojson. It's a map of DC with neighborhoods, put together by Justin Grimes.

Right now, I'm just trying to visualize this map on notebook. Here's my code:

import vincent
map=r'https://gist.githubusercontent.com/justgrimes/a63e8ec28868d8ce337e/raw/13cd7d8867e579d8b4f6b44f002a99940fba0504/DCNeighborhoodBoundariesWaPo.geojson'

geo_data = [{'name': 'countries',
             'url': map,
             'feature': "features"}] 
vis = vincent.Map(geo_data=geo_data, scale=5000) 
vis

but I have nothing in the output. What am I doing wrong here?

I don't yet know much about GIS and Python.

Answer 1

You have to load Vincent JS parts with vincent.initialize_notebook()

You need to transform the GeoJSON to TopoJSON (use Mapshaper) as Vincent support only TopoJSON (or I missed something too). See the official doc to understand TopoJSON

The key DCNeighborhoodBoundariesWaPo in 'feature': "DCNeighborhoodBoundariesWaPo" was deduced from TopoJSON objects

You do not display you visualisation with vis.display()

See below working sample for a complete overview.

import vincent

vincent.initialize_notebook()

map=r'https://gist.githubusercontent.com/ThomasG77/9e05f8cd04f0406e4529/raw/1974a51fbe081c83c3c20da7bcdb091a3d6604e2/DCNeighborhoodBoundariesWaPo.json'

geo_data = [{'name': 'whatever',
             'url': map,
             'feature': "DCNeighborhoodBoundariesWaPo"}] 
vis = vincent.Map(geo_data=geo_data, scale=150000, translate=[-40480], projection='albersUsa') 

vis.display()

A last remaining problem is the fact I was able to zoom to DC but without using really a recipe (more try/test...), with translate (IMO, Vega/Vincent sucks for this when zooming on a specific part of a country or region)

If you have a better way of doing for the last part, I will be happy to learn how!

Answer 2

Not knowing vincent very well, could I offer that your map variable is just a string and not the resulting geojson you expect? Or you could validate the geojson at http://geojsonlint.com/