  What people choose to see, like, or remember is of profound interest to city
planners and architects. Previous research suggests what people are more likely
to store in their memory - buildings with dominant shapes and bright colors,
historical sites, and intruding signs - yet little has been done by the
systematic survey. This paper attempts to understand the relationships between
the spatial structure of the built environment and inhabitants' memory of the
city derived from their perceptual knowledge. For this purpose, we employed the
web-based visual survey in the form of a geo-guessing game. This enables us to
externalize people's spatial knowledge as a large-scale dataset. The result
sheds light on unknown aspects of the cognitive role in exploring the built
environment, and hidden patterns embedded in the relationship between the
spatial elements and the mental map.
