A web-based platform to support interactive environmental planning in Southern California is currently being developed, as part of the Green Visions Plan project. The main goal is to provide tools for municipalities and community-based groups to identify candidate project sites that can: (1) promote more equitable park and open space access for local residents; (2) protect and restore biodiversity; and (3) protect and enhance watershed health. The Interactive Park Analysis Tool operates at the parcel level and provides estimates of potential park user demographics in a series of customized reports, as illustrated in this article. The Interactive Park Analysis Tool and supporting map viewer platform (like the other tools) utilizes a client/server system architecture that provides users with access to large, detailed geospatial datasets. The system architecture and implementation is described, and a case study illustrates system functionality. Work is now underway to expand the platform to include additional online tools to facilitate the evaluation of biodiversity and watershed health within the study area.