This chapter outlines the theoretical and methodological frameworks for analyzing urban street canyon morphology and its role in regulating solar radiation at street level. It introduces critical geometric indicators—sky view factor (SVF), tree view factor (TVF), and building view factor (BVF)—to quantify urban radiative environments, emphasizing their relevance to microclimate studies, UHI mitigation, and thermal comfort. Traditional quantification methods, including 3D modeling and fisheye photography, are contrasted with emerging street-sensing techniques using google street view (GSV) panoramas, which offer scalable, high-resolution urban mapping. This chapter delineates the physical components of street-level solar radiation (direct, diffuse, and reflected) and their dependence on solar geometry, atmospheric turbidity, and canyon structure. Challenges in high-density cities, such as Hong Kong, are highlighted, where complex geometries and vegetation obstruct conventional modeling. A novel GSV-based approach is proposed to overcome limitations in existing methods, enabling precise, large-scale quantification of view factors, and solar irradiance. By integrating computational tools like pyramid scene parsing networks (PSPNet), this methodology enhances urban climate assessments, supporting sustainable planning and heat resilience strategies. The discussion underscores the necessity of accurate street-level radiation modeling for improving human health outcomes and urban ecosystem services in rapidly urbanizing environments.