That's how I started building GitHub Audience Atlas. It visualizes a GitHub user's network and shows them on a map by categories: followers, following, and ghosts (those who don't follow you back). On the left, you can see the list of your audience by country (for those with a location set).

It is still under development, so new features and bug fixes are to be expected.

It's totally client-side, with nothing stored on any server for Security. I used React/TypeScript to handle the rendering and D3 for the visualization (essentially, it just does the math for the projection while React handles the rendering). I also coded the geocoding algorithm myself because I wanted to keep it lightweight.

Demo: https://github-audience-atlas.vercel.app/ Source code : https://github.com/ThierryRakotomanana/Github-Audience