This is in answer to this Stack overflow question. The question was about how to represent projected or local coordinates as opposed to geographic or earth projections. This topic has been covered in this google groups discussion using d3 geometry streams. This example presents different alternative to achieve the same result.
Essentially, d3's existing 2D path generators are used and the appropriate part of the geojson file is passes up.
Modified http://d3js.org/d3.v3.min.js to a secure url
https://d3js.org/d3.v3.min.js