Visualization of urban heat and light at the pedestrian level

ABSTRACT This research aims at developing a methodology for integrated visualization of diurnal/nocturnal urban heat and light exposed to pedestrians. Heat and light are major environmental qualities affecting the visual and non-visual experiences of pedestrians in urban spaces. The configuration of urban layouts, including built-up area, density, and surface features, could modify the quality of heat and light exposed to pedestrians. The pedestrian-level integrated visualization of urban heat and light still requires further studies in relation to the individual's field of view, physical elements, and spatiotemporal variations. This research combines thermography, low-dynamic range (LDR) photography, and high-dynamic range (HDR) imagery with thermometry to discuss the typologies and attributes of heat and light which are offered within a 360-degree field of view of pedestrians in two urban layouts in Quebec City, Canada. The thermographic and thermometric methods reveal the non-visual qualities of urban spaces in terms of heat. The LDR photography and HDR imagery display the visual qualities of urban spaces related to light. The selected layouts include a densely constructed fabric and a green open urban space to represent diverse spatial configurations and surface materials. As an exploratory study, a 24-hour survey during a summer day is conducted to use the combined methods to capture and discuss the physical and environmental qualities of the urban layouts. The combined image-based methods foster an enriched, comprehensive visualization and discussion of diurnal and nocturnal patterns offered by air and surface temperatures and lighting conditions. The combined image-based approach enables visualizing and comparing typologies of urban heat and light in relation to building density, trees, greenery, and surface characteristics. Overall, the proposed methodology promotes the integrated visualization approach to study urban environmental qualities which can inform local communities, designers, and decision-makers about the impact of design configuration, material choices, and retrofit solutions.