Poster / Side project
I wanted a poster, but they were all paid
So I made my own in an hour of free time. Pick any place on earth, choose a paper size, download a file a print shop can put on a wall.
My role: everything. 2026.
00 / Why
Free, because it costs nothing to run
City map posters usually sell for twenty to forty euros, while the map data underneath is free OpenStreetMap. Here everything is drawn in the visitor's browser, so there is nothing to pay for: no watermark, no account, no limits.
01 / Architecture
Four steps, no map library
Vector tiles fetched straight from OpenFreeMap and decoded in the browser. Roads arrive already classified and already generalised for their zoom level, so a poster of a whole city does not drown in driveways.
Web Mercator by hand — four short functions. The bounding box is derived from a centre point and a width in kilometres, then a projector maps every coordinate into the poster's own pixel space.
The poster is emitted as an SVG string. It is split into a map body and the chrome around it, because one walks tens of thousands of coordinates and the other is a handful of elements — typing a title should not re-project a city.
SVG is the real deliverable — a print shop scales it to any size with no loss. PNG exists alongside it, rasterised at the pixel count the chosen paper size and DPI imply.
02 / Shipped
What is in the product
Attribution to OpenStreetMap is baked into the poster itself rather than the page, because the file is what leaves the site.