The Wikimedia project has a series of excellent, heavily annotated free maps of the London Underground — a boon in an era where the London Underground treats riders who remix the transit map as criminals and threatens to sue them.
A PHP script processes the line definitions to create list of stations on the line, calculates coordinates of the control points for bezier curves, and then outputs the graphic as an SVG file. The SVG files are then fine tuned in an SVG editor (text placement, mostly) and rendered as PNGs.
(via Plasticbag)
