This example belongs to the presentation made to the OSGeo local group in Barcelona Geoinquiets The example is an adaptation from Mike Bostock's Symbol Map example
Modified http://d3js.org/d3.v3.min.js to a secure url
Modified http://d3js.org/topojson.v0.min.js to a secure url
Changed /mbostock/raw/4090846/us.json to a local referenece
https://d3js.org/d3.v3.min.js
https://d3js.org/topojson.v0.min.js