In The Death and Life of Great American Cities,Jane Jacobs described four conditions that generate urban diversity.
Old buildings mean affordable space, the ground where new ideas take root. That is why Jacobs called this condition essential. But she asked for old and new standing together, so an urban district carries two measures at once: how old, and how mixed.
Hierarchical clustering reveals seven types, each with a distinct building age composition, spanning the continuum from incremental to instant development.
Temporal Fingerprint
Matrix
Why do urban areas that grew gradually sustain a denser, more diverse retail life than the ones built at once? And how can building age be operationalised to read the temporal fingerprint of a city?
A city is never built all at once. It accumulates, building by building, era by era. Every neighbourhood carries that record in the ages of its buildings.
Some neighbourhoods grew across centuries, while others appeared within a decade. The difference is visible in the urban fabric, and it can be measured.
Where the urban fabric accumulated over generations, retail is denser and more varied. Where it arrived all at once, there is less of it, and less variety within it.
One of the conditions that accompany dense and varied retail in a district, then, is what Jacobs described: buildings varying in age and condition, mingled over time rather than delivered whole.
Temporal Fingerprint Matrix
An interactive companion to a morphometric study of Jacobs' neglected condition: how building age and building age diversity, taken together, distinguish incremental from instant urban development, and how these temporal patterns shape retail density and diversity across Amsterdam, Rotterdam and The Hague.
Publication
Tümtürk, O., Efeoğlu, H. E., Akay, M. & Çalışkan, O. (2026). Building age diversity and retail patterns: A morphometric exploration of Jacobs' neglected condition through the Temporal Fingerprint Matrix.
Urban Studies · doi.org/10.1177/00420980261462840
Funding
Onur Tümtürk acknowledges funding from the Fulbright Postdoctoral Scholarship Program (FY-2025-TR-PD-04), held at the MIT Senseable City Lab during the writing of the article.
Data
Building ages from the Netherlands' BAG public registry (Kadaster). Retail from OpenStreetMap. Basemap © CARTO, © OpenStreetMap contributors.