I am working on a project where it is necessary to display maps of countries and cities using d3.js.
Actually, D3 supports GeoJson format. Usually, I guess, GeoJson format is converted from some other format.
I found some places with this GeoJson data:
http://mbostock.github.com/protovis/ex/countries.js
But, this is only a list of countries, I am looking for some service or program that gives me the ability to set an ID, get this format, and convert it to GeoJson, or get it in GeoJson better.
Thanks!!
Does this need to be a service? Here's how I've approached this in the past, using free/Open Source tools:
Download public-domain shape files from Natural Earth Data
Use Quantum GIS to convert .shp to .geojson (one step, under "Layer > Save As...")
Now you have hi-res GeoJSON data. Here, have some countries.
This is a really big file, though, so you'll want to split it up. But you don't need a service for this, just static files for each country, named by ID. This would be easy enough to produce with a script in your utility of choice (Python, Ruby, node.js).