Circle, square, and triangle can be found in manifold human activities: ornament, painting, formative art, plaything, engineering mechanism, and so on. In architecture, a simple geometric figure determines an architectural form beyond differences in regions, era, scale, and building type. Our research focuses on architectural planning composed of a circular form (referred to as the “circular plan”), which includes many examples and examines it as a model of architectural geometry to highlight the relationship between geometry and contemporary architecture.

To clarify a structure of classification and an existence of regularity in contemporary architecture that comprises a circular plan, we conducted Cluster Analysis, Correlation Analysis, Multiple Correspondence Analysis (MCA) and Canonical Correspondence Analysis (CCA) using qualitative data related to presence-absence of compositional elements and quantitative data related to size.

Below is a summary of the findings of this study:

1. Explication of the statistical relationships between compositional elements within a circular plan, by using Correlation Analysis and Cluster Analysis.

2. Clarification of the five morphological types established in contemporary architecture with a circular plan by using MCA and Cluster Analysis.

3. Discovery of the latent structures that define the morphological classification based on tendencies of similarity and difference in compositional elements;

　a. Centrality and Noncentrality of the compositional elements.

　b. Continuousness and Discreteness of internal space.

4. Explication of the correspondence relationships between the size of a circular form and morphological types by using CCA.

5. Examination about samples that are composed of several different morphological compositions.