Measuring and assessing architectural centrality: configurationally-derived and visibility-based centrality in the plans of Palladio and Wright

Architectural ‘centrality’ is widely invoked in historiographic interpretations of plans, yet it is rarely defined in a form that can be rigorously measured or evaluated. This study operationalises two idealised centrality tendencies, ‘inward’ and ‘outward’, treating them as non-binary constructs that can coexist and vary by degree. To do this, eight canonical domestic plans, previously described as exhibiting centrality — four villas by Andrea Palladio and four Prairie houses by Frank Lloyd Wright — are modelled as plan graphs and visibility graphs to compute configurational centrality (closeness and betweenness) and visibility centrality (visual connectivity and through vision). Centrality values are standardised using z-scores to enable cross-case comparison. Results indicate that Palladian villas consistently exhibit stronger core accessibility and more concentrated co-visibility, in line with theorised conditions. However, outward mediation and through-visibility are not consistently stronger in Wright's Prairie houses, complicating the strict inward-versus-outward distinction often found in architectural histories. The contribution of this research is that it extends existing Space Syntax and VGA practice by making the architectural meaning of ‘centrality’ explicit before measurement and by pairing configurational and visibility constructs to evaluate, rather than assume, historiographic claims. The framework provides a reproducible basis for comparative plan analysis and for future triangulation with cultural and phenomenological evidence.