This study aims to develop and test a tool for analyzing visual structures of day and night-scapes from an ecological approach. Gradient of texture, a concept based on Gibson's theory on visual perception, of urban day and night-scapes are compared by quantifying the roughness of textures in digital landscape images. Results show that roughness of texture decreases by distance in day-scapes while it increases in night-scapes, showing differences in visual structures between day and night.
