Review of Research on Non-Conforming Urban Expansion: Measurement, Interpretation, and Governance

Abstract

Spatial plans are widely used as a basic tool for regulating urban expansion. However, land development beyond zones planned for urban development is prevalent worldwide, posing a serious challenge to the implementation of spatial plans and their effectiveness in regulating urban expansion. This paper presents a review of research progress relating to the measurement, interpretation, and governance of non-conforming urban expansion. Spatial conformance between actual land use and plans is the basic criterion for evaluating the effectiveness of plans in containing urban expansion. Accordingly, scholars have developed multiple indicators and methods for directly and indirectly measuring non-conforming urban expansion. Previous studies have elucidated external and internal factors influencing non-conforming urban expansion, revealing the external conditions of non-conforming urban land expansion and the factors driving decisions on site selection for non-conforming land development. To address the existing issue of non-conforming urban land and to prevent and control future non-conforming urban development, scholars have proposed multiple governance strategies. Drawing on existing research progress, we offer suggestions for future academic research in this field.