Space Constitution of Sunken Gardens and Visual Connection between Their Aboveground and Underground Levels

摘要

This study aims to elucidate the relationship between the attraction to the upper or lower levels and the space constitution of sunken gardens of various sizes and shapes. This study begins with denning a sunken garden as "a garden or plaza dug down from the ground surface. " Examples of sunken gardens were then collected and categorized according to their shapes. Based on the categories, a total of 20 sunken gardens located in Hamamatsu, Nagoya, Kyoto, Osaka, and Kobe were selected as test spaces. In each test space, a pan-around view from a point overlooking both upward and downward directions was videotaped using a high definition video camera. The images were presented to subjects in random order for evaluation of the intensity of their attraction by the magnitude estimation method. By tallying and analyzing the test results, the following were found: (1) The intensity of upward attraction can be related to the shape of the space. In other words, the intensity of attraction is high when the travelable area of the underground space is large; the length of the short side of the opening on the ground is large; and the depth from the ground level to the underground plaza is small. (2) The intensity of downward attraction can be related to the connecting features. The downward attraction of the type connecting an aboveground plaza with an underground mall is strong, whereas the downward attraction of the type connecting streets with the basement of buildings is weak. (3) Both upward and downward attractions are increased by the presence of greenery in the space ahead and by an open space that offers a glimpse of the space ahead. A building attached to a sunken garden reduces the attraction in both upward and downward directions.