Visual Impact Analysis and Control Method of Building Height for Landscape Preservation of the Traditional Gardens: A Case Study on the Suizenji Jōjuen in Kumamoto City

Abstract

With the progress of urbanization,dlc the traditional gardens are increasingly visually destroyed by the construction of high-rise buildings around them. This study aims to evaluate the degree of landscape destruction caused by high-rise bulidings using visual impact analysis, and present a quantitative approach for controlling the height of buildings using GIS. This paper selected Suizenji Jōjuen, a traditional Japanese strolling garden located in Kumamoto City as a case study. Firstly, a 3D urban model was constructed. Then, three main view points were selected as observation points in order to simulate real vision of observers, and the contours of trees around the garden were described by the vertical and horizontal angles from each observation point. Secondly, the study focused on two visual impact factors: angle of elevation and distance, and used angle of elevation analysis to calculate and evaluate the degree of landscape destruction caused by buildings around garden. This analytical method was based on the height of buildings and the distance from observation points to buildings. Thirdly, a virtual vision plane was constructed, which was formed by a large amount of extension lines linking from observation points to the contours of trees. Based on the vision plane, a quantitative control method of building height was presented, and the height of buildings was limited according to the distance away from the center of the garden. This research, could not only contribute to the landscape preservation of Suizenji Jōjuen, but also suggest a quantitative approach for controlling the height of buildings for reference for the building height restrictions around traditional gardens in other cities.