Convert GeoJSON to TopoJSON

Glad you asked, oh handsome OP.

Install topojson

From the command line (Mac OSX 10.8, assumes homebrew installed):

brew install node.js
npm install -g topojson

Convert The Data

topojson -o output.json input.json

The function to create a topojson from a geojson in topojson has been moved to geo2topo

npm install topojson-server -g
geo2topo input.geojson > output.topojson

I ported the TopoJSON code from JavaScript to Python, following the exact same format Mike uses in his library (along with his +300 tests).

If you feel better with Python, just install the library by running:

pip install pytopojson

And then run:

python geo2topo.py geojson_file

You can also use a quantization parameter. Just use the -h argument to see how it works.

Let me know if this was helpful to you!