Today we announce TileMill, a project that brings map design to new audiences and pushes a modular, open source stack that's fast, easy to use, and intelligent.
We built TileMill to support our mapmaking and to enable artists to design maps. Right now it's accessible to anyone with a bit of technical experience who's willing to run through the installation directions and is ready to learn and tinker - and possibly break a few things (the issue tracker is open).
TileMill connects Carto, a powerful, CSS-like styling language, with the high-quality output of Mapnik.
There are a lot of new things happening in TileMill, and the environment is made for learning. There's both a user manual for those just getting started and a built-in reference for on-the-fly technical questions. Thanks to Mapnik's reference project, the editor can also highlight correct attributes and suggest corrections when values are invalid. And after you've designed a map, you can export it to MBTiles to read it on MapBox for iPad. You can also export to PNG or PDF for websites or reports.
Right now you can add shapefiles, GeoTIFF rasters, simple KML and GeoJSON as data, pulling from a local disk or from Amazon S3, thanks to knox.
Under the hood of TileMill is a combination of open source projects - Mapnik for map rendering, express as a server-side framework, Backbone.js for the client-side, CodeMirror in the editor, carto for the styling language, node.js, and many others.