In the past few months, we’ve been making a lot of maps at TrailBehind, and since we’re using open data, along with MapBox’s open source TileMill tool, we thought it would be appropriate to open source the stylesheets we developed, too.

You can now check out all of our CartoCSS style sheets and related assets from GitHub. We have styles for tiling data like state hunting game zones, US river charts, topo maps, and more. Pop over to our maps page to browse the live maps that we made with TileMill, CartoCSS, and Postgres. The is a living project, and we expect to add many more styles in 2014.

We hope that our work can make it easier for anyone out there working with open data, particularly the open US government data we are interested in. We also want to note that if you create an open CartoCSS style sheet, we’d be happy to host and publish just about any map you want to use in Gaia GPS. Pull requests are welcome!

When we founded this company and started writing apps many years ago, we always avoided cartography, instead choosing to work with 3rd parties to get our maps. We still pay to license a bunch of great maps, but MapBox’s stack of tools has thrown open the doors for us to make maps. Given we had no previous experience, that means two things – these tools are great, and you can do it too.

Here’s one of our styles, that shows some OSM data in the style of USGS topos.

OSM data styled like USGS topos.