pippa

https://github.com/gene-ressler/pippa

Draw dots on maps by lat/lon or zip code. Includes a library of 30 map backgrounds, and associated geocoding configuration data, and a table of US zip codes with their approximate centroids as latitude and longitude. Exposes the ImageMagick image and coordinate conversions so that overlaying labels, lines, and other features on dots is possible. Renders as a blob suitable for e.g. Rails send_data as an img tag src and writes files in any supported ImageMagick graphic format.