The idea that ordinary people should have a say in decisions affecting their surroundings is now well accepted, though how to achieve this in practical terms remains a challenge. Where focus groups and town hall meetings dominated in the past, Web-based surveys have become the tool of choice for engaging the public in environmental planning, or activities aimed at changing the way humans interact with the non-human, natural environment. Environmental planning is inherently spatial, well suited to map-based representations characteristic of geographic information systems (GIS). Yet, planning is conducted for purposes driven by values and interests—concepts that often lack direct spatial references, making their integration within a GIS framework difficult. This dissertation explores techniques for using maps to understand how people think about environmental issues, ultimately in service of planning. It begins with digital participatory mapping—Web-based crowdsourcing of geographic information—conducted in a country where less than 20% of households owned a desktop or laptop computer in 2015. Indonesia, which operates a national online participatory mapping portal, was the site of an ethnographic case study that examined implications of Web-based participatory mapping in a place where computers are uncommon. Using the online collaborative planning tool SeaSketch, two map-based surveys were administered to locals and visitors in rural Bali, one on non-biodegradable litter and the other on tourism development in the region. No correlation was found between prior computer experience and the locational accuracy with which participants mapped features, though experienced computer users tended to map more features. Their responses, including digital maps annotated with place descriptions, were analyzed through a combination of spatial density analysis and text mining techniques, namely word clouds and topic modeling. The resulting geovisualizations were used to interpret common themes invoked by participants, such as marine resources and civic responsibility, and relate those themes to the spatial pattern of features mapped across the land- and seascape. Based on these themes, two simple plans are proposed, one addressing waste management and the other the future of tourism in West Bali. Finally, an alternative planning methodology is proposed, one that expands upon the straightforward participatory mapping approach demonstrated here to systematically relate intangible aspects of participants’ perspectives to geospatial data. Together, the work is intended to improve how digital participatory mapping is conducted in rural, non-Western settings; provide new ways of combining spatial and textual data analysis that help planners interpret annotated maps; and from a critique of this approach propose a more comprehensive methodology to incorporate notions of function, purpose and value into a geospatial design framework for environmental planning.