The quality of outdoor environments after dark is as important as during daylight hours, particularly in regions where long autumn and winter seasons limit natural light. Outdoor lighting plays a central role in shaping nighttime urban environments, yet it is often treated as a secondary or purely technical task rather than a multidisciplinary design responsibility that integrates social, environmental and economic goals.

People are the primary beneficiaries of outdoor lighting, making their experiences an essential source of knowledge for understanding and improving urban environments after dark. Participatory mapping, particularly Public Participation Geographic Information Systems (PPGIS), has become an established approach for collecting place-based experiences in urban and environmental research. However, its application to outdoor lighting and nighttime urban experiences has remained limited.

This doctoral research project, conducted at Aalto University between 2021 and 2026, investigated how PPGIS can be applied to study outdoor lighting and urban experiences after dark. The project examined the capacity of participatory mapping to capture people’s place-based perceptions of illuminated environments, including perceived overall quality of street lighting, spatial brightness, qualitative place-based feedback on lighting, and reassurance after dark. It also explored how experiential PPGIS data can be integrated with lighting-specific geospatial datasets, including lighting infrastructure, road lighting classifications and nighttime aerial imagery. Through this work, the project contributed to the methodological development of PPGIS for outdoor lighting research while demonstrating its practical value for evidence-based, human-centred lighting design, planning and decision-making.