New York City
(photo CC Jen Hudon)
Several groups in the NYC area are using PLOTS tools including balloon mapping to document at-risk ecological sites.
Gowanus Canal Mapping
New York City is home to the "Gowanus division" of Grassroots Mapping, which is conducting a monitoring project of the Gowanus Canal cleanup.
Check out Grassroots Newark:
as well as a recent workshop held at Union Square: http://grassrootsmapping.org/search/parsons