We just overhauled the maps for the Federal Education Budget Project with new custom slippy maps, using TIGER Census data along with OpenStreetMap data. The new mapping stack lets users browse all the nation’s school districts much faster, with dots sized to indicate reading achievement and other variables.

Here’s a look at the new maps:

This is a big change from the first version of the site that utilized static maps, since the map can be panned across the entire country. To make this possible, district information is only loaded when it comes into view – a feature of the OpenLayers Javascript library.

Why custom maps?

For the Federal Education Budget Project, custom maps were essential because, rather than mapping points relative to transportation or town boundaries commonly found on maps, the site’s maps portray school district boundaries. As tools like Mapnik and TileCache have approached maturity, it has become possible to make maps that are both custom and rich in interaction. So now on the site you’ll see beautiful maps of school districts, with specific highways and county boundaries added for context.

Generating custom tiles

Instead of rendering an image for each map, the new maps operate from a vast collection of map tiles, generated entirely within Amazon’s computing cloud and using Mapnik and TileCache sourced with OpenStreetMap and TIGER data from the U.S. Census Bureau. The ability to quickly render tiles and store them in the S3 system, and expose them to the world through the CloudFront content distribution network makes new levels of agility possible, rendering layers more quickly and distributing them immediately. Will White blogged about our Amazon cloud stack in more details.

For more background on this project, we recently wrote about how the New America Foundation is making an enormous amount of data about the U.S. public education system freely available through the Federal Education Budget Program. The new site, which launched in May, features highly customized maps of the 14,000 school districts around the country.