From the BP Oil Spill to the Gowanus Canal Super Fund site, Grassroots Mapping and the Public Laboratory for Open Technology and Science work to empower citizens around the world. Communities engage in citizen cartography and create aerial images with low-cost, DIY, open sourced technologies. This method of mapping creates on-demand imagery that’s 30 to 50 times higher resolution than what’s available via Google Maps. It allows people to document, to lobby and to enact change in their neighborhoods. The Public Laboratory community has expanded to organize projects around the world. Recently recognized with the award of $500,000 Knight Foundation grant, that work continues to expand. We’ll discuss the unique challenges and obstacles of scaling citizen science, IRL community development work, and online technology engagement.