Comparing Volunteered Data Acquisition Methods on Informal Settlements in Mexico City and São Paulo: A Citizen Participation Ladder for VGI

In the early 2000s, Web 2.0 technologies prompted an explosion in geographic data that include Volunteered Geographic Information (VGI), a set of methods that brings user contribution to the center of data acquisition. These methods increase the capacity of community-driven and local initiatives to create geographic information and close existing data gaps in authoritative sources. Informal settlements constitute an example of where a major vacuum exists, as maps are often incomplete, outdated, or imprecise. However, quality issues regarding VGI frequently arise, as do questions on citizen participation and empowerment. This study explores how different VGI approaches support citizen participation and user empowerment, in tandem with the opportunities and limitations of VGI to map informal settlements in Latin America. We propose a VGI comparison framework to evaluate citizen participation in two informal settlement mapping projects in São Paulo and Mexico City. Such a framework includes four categories: (1) required material resources; (2) required geographic information system (GIS) literacy; (3) user agency; and (4) involvement of research subjects. The results demonstrate that higher citizen involvement in São Paulo stems from the inclusion of residents through participatory mapping methods. Conversely, the Mexico City’s case demonstrates how crowdsourcing may happen irrespective of and contrary to the goals from those represented in the data. We suggest that VGI is a powerful tool for generating timely and precise data on informal settlements, but research subjects should have agency over geographic information collected about them.