the city grew up

in july I wrote that a repo is a city. that Atlas was a 48-hour build: flat maps, one theme, no dependency arcs. it took 2nd of 503 projects at the IBM Bob hackathon, and that exact state is tagged v1.0-hackathon in the repo, permanently. what I kept building afterwards now lives at atlascity.dev.

the flat map went isometric, and the encoding got stricter on the way up. height is lines of code on a log scale, so the skyline is the size distribution of the repository. colour is the top-level directory a file lives in, and each of those becomes a district on its own plate. footprint encodes the kind of file rather than its size, because size already lives in height, and spending two channels on one variable wastes one of them.

the load-bearing files get named now. entry points, where execution starts, read these first. hubs, imported by the most files, where changing one ripples. and the unusually large, which is often where complexity hides. hover a building and a tooltip names it; click, and an inspector opens with the details.

underneath, it is still the same four agents from the hackathon weekend, one request, no model in the loop. the ingester streams the repository as one archive, with no credentials, nothing uploaded, nothing stored. the parser classifies every file, counts its lines, and resolves local imports. the layout settles a force simulation so related files end up as neighbours. the annotator scores centrality and promotes the few files worth naming. deterministic on purpose. the same repo always draws the same city, and that is what makes two maps worth comparing.

big repositories keep their shape too. a map draws at most 500 files, but the cut is not arbitrary: a prioritisation pass keeps entry points and the highest-value source files and samples the rest across directories, so the outline of the project survives even when the file count does not.

the rest is finish. two themes, carbon and paper. PNG export at up to 3× with a caption band naming the repository. still MIT, still on github.

paste in a repo you know. last time I asked whether the city looked right. this time it should read right.