The location logic of informal retail: dual-scale evidence from street food vendors in Hangzhou

Street food vendors (SFVs) form an important part of nighttime retail supply in cities. However, they operate without fixed premises and change locations over time. Understanding these patterns is essential for designating vending sites and planning the nighttime economy. Focusing on nighttime SFVs in the main urban districts of Hangzhou, this study applies an XGBoost, SHAP, and GAM framework with spatial autocorrelation analysis at the block and street scales. The analysis identifies associated factors, differences across scales, and spatial alignment between designated sites and actual SFV locations. At the block scale, SFV distribution is positively associated with working population density, shop rent, and metro accessibility, converging on mature commercial cores. At the street scale, associations shift toward micro-scale nodes such as metro entrances and parking facilities. Designated sites and actual locations align globally but diverge locally. These findings extend the discussion of classical retail location theory to informal retail. Fixed premises, rental arrangements, and purposive consumption may take different forms in informal settings. Their relevance therefore requires explicit consideration. The findings support a spatial guidance strategy combining block-scale zoning with street-scale site allocation, offering empirical grounding for nighttime economy planning and urban governance.