Abstract
<title>Abstract</title> <p>Background Understanding lived food environment experiences remains challenging due to the reliance on conventional Geographic Information System (GIS) measures, which typically use static, residence-based exposures and therefore fail to capture individuals’ complex interactions with food environments. This study aimed to develop and validate the Public Participation Geographic Information System Food Environment Questionnaire (PPGIS-FEQ), a map-based questionnaire that integrates spatial and non-spatial data. Methods The PPGIS-FEQ was developed and validated through a four-phase iterative process: (1) questionnaire development, (2) validation and translation, (3) field test and (4) PPGIS data quality assessment. Questionnaire items were informed by a literature review and in-depth interviews with 17 adults. Content validity was assessed through five rounds of multidisciplinary expert reviews, while face validity and cognitive testing were conducted with 10 adults. Following pilot testing (n = 30), field testing was conducted with 306 participants. PPGIS data quality was evaluated using ArcGIS Pro, focusing on geometric accuracy, completeness, and spatial distribution patterns. Results The final PPGIS-FEQ comprises three sections: participant screening (4 items), sociodemographic information (11 items), and participatory mapping components (8 items). Spatial data quality assessment demonstrated high geometric accuracy (97.40%) and high completeness (95.75%-100%). Mapped food outlet locations exhibited significant spatial clustering. Conclusions The PPGIS-FEQ is a valid and scalable participatory map-based instrument for capturing real-world food acquisition behaviours. By integrating outlet-specific perceptions and food purchases with individual-level sociodemographic data, it moves beyond conventional measures, enabling person-centred assessment of food acquisition behaviours while retaining population-level applicability. Its adaptable design allows the incorporation of context-specific food outlet typologies, supporting the generation of locally relevant evidence to inform targeted policies and interventions in diverse settings. Trial registration: Not applicable.</p>