Development of methods for delineating urban areas based on urban density and its application to evaluating urban shrinkage

2020 Fiscal Year Final Research Report

• Project/Area Number: 17K12978
• Research Category: Grant-in-Aid for Young Scientists (B)
• Allocation Type: Multi-year Fund
• Research Field: Social systems engineering/Safety system
• Research Institution: The University of Tokyo
• Principal Investigator: Hiroyuki Usui 東京大学, 大学院工学系研究科(工学部), 助教 (70748219)
• Project Period (FY): 2017-04-01 – 2021-03-31
• Keywords: 既成市街地 / 密度 / 人口集中地区 / 居住誘導区域 / 都市のスポンジ化 / 平均費用最小化

Outline of Final Research Achievements

A bottom-up method for delineating urban areas is developed which is based on building locations. This method consist of the following three steps. First, buildings whose nearest neighbor distance (NND) is shorter than a criterion are specified as built clusters. Second, built cluster's size greater than a criterion are delineated as urban areas. Third, the criterion regarding the NND of buildings is optimized which can minimize the average total cost of road networks. Urban areas delineated by this method are compared with densely inhabited districts (DID). Also, using this method, a new method is developed for evaluating whether or not vacant plots are randomly generated and accumulated spatiotemporally. It is found that the random generation of vacant plots does not tend to continue in the same urban areas. Rather, in most urban areas, this process is a temporary phenomenon. Nevertheless, once vacant plots are randomly accumulated in an urban area, this process tends to continue.

Free Research Field

都市計画，社会システム工学，地理学

Academic Significance and Societal Importance of the Research Achievements

本研究が提案する既成市街地の画定方法は，既成市街地を構成する最小な空間単位である建物を基礎とし，既成市街地の形態と都市運営費用の関係を明示的に分析できた点において，学術的な意義を有する．また，社会的な意義として，建物の分布に基づいて既成市街地を画定する方法を構築し，既存の既成市街地である人口集中地区（DID）との比較分析を精緻に行うことで，居住誘導区域等の設定や既成市街地の縮退の評価への貢献が挙げられる．