Noah Veltman, WNYC (@veltman)
Tom MacWright, MapBox (@tmcw)
- QGIS, for using shapefiles, joining data, and lots of other things
- Leaflet, for making slippy maps for the web
- MapBox, for almost everything
- Google Maps API, the granddaddy of them all
- D3, for creating SVG maps for the web
- MapStack, for designing quick, custom map images
- CartoDB, for creating/hosting data-driven web maps
- Kartograph.js, for building SVG maps for the web
- geojson.io, for browsing/editing a geodata file
- Google Maps styling wizard, for creating custom background styles for the Google Maps API
- TopoJSON, a file format for storing geographic features as a topology
- ogr2ogr, a command-line utility for all sorts of processing and conversions
- Mapstarter, for getting a quick start on a web map
- ADC4GIS converter, for converting to/from GeoJSON
- Distillery, for converting GeoJSON to TopoJSON
- Mapshaper, for simplifying or converting shapefiles, GeoJSON, and TopoJSON
- shapefile, a Node.js module for converting shapefiles to GeoJSON
- shp2json, another Node.js module for converting shapefiles to GeoJSON
- Mapschool, by Tom MacWright
- ForJournalism mapping session, by Ken Schwencke
- Learning Lunch on maps, by Noah Veltman
- Let's Make a Map, by Mike Bostock
- Responsive Maps with D3, by Chris Amico
- A Leaflet.js tutorial, by Becca Aaronson
- Another Leaflet.js tutorial, by Mike Tigas and Noah Veltman
- US Census Bureau, for detailed data about the US (mostly shapefiles)
- Natural Earth, for downloads of basic natural/political boundaries for the entire world
- OpenStreetMap, for detailed, mappable data about almost every place in the world
- NOAA geodata files
- USGS geodata files
- The Los Angeles Times Boundary Service (for Los Angeles)
- The TribApps Boundary Service (for Chicago)
- The MinnPost Boundary Service (for Minnesota)
- Try your local/state government. Many of them have GIS sites where you can download detailed files of districts, roads and more. Try searching for things like "[name of place] shapefile" or "[name of place] gis."