How to generate a github-like Impact Graph?

Question

Is there some program out there (or some magical git plugin I've missed) to get an impact graph or something similar from a git repo without going through github? I'm unsure where I'd begin exactly to write my own, as far as data collection goes (I can generate graphs). I assume there's some flags I could pass to git-log to get commits and authors, but I'm unsure how to get impact (sum of lines added/removed, or maybe total bytes added/removed), and perhaps even skip certain files from consideration.

Answer 1

This SO question provides some answers:

git log --author="<authorname>" --pretty=tformat: --numstat

and for the graph itself, I know about this jQuery program (but I haven't tested it), based on json-formatted data. Illustrated here, reported by this message)