Algorithmic justice and groundtruthing the remote mapping of informal settlements: The example of Ho Chi Minh City’s periphery

The significant advances made in interpreting satellite imagery to monitor urban expansion and informal settlements has made important contributions to urban studies and planning. This paper focuses on the under-examined dimensions of how improvements to classifications of urban areas are not only a technical challenge but lie at the society/technology nexus. We examine why three different research groups produced different urban land use classifications of Ho Chi Minh City, Vietnam from remote sensing images. We trace how a confluence of factors including how the technology intersects with field conditions, researcher assumptions and discretionary choices, and institutional norms and agendas shaped the differences in their results. The different spatial facts they produced raises the issue of adapting algorithms for not only technical accuracy but appropriate social use. In the case of detecting informal settlements, our study finds that groundtruthing through fieldwork or collaborative partnerships is needed to not systematically overlook vulnerable populations and misinform urban planning decisions.