Mapping time & space: four-dimensional layers of the public realm

The practical consideration of the time-dimension with regard change in cities has an interesting history. Stewart Brand (1994) famously provided a framework for considering change within the urban environment with his idea of ‘shearing layers’, itself based on earlier ideas from Duffy (& Henney 1989, 1990). In each case, a loose hierarchy from relative permanency of the site, the building structure / shell and to a lesser extend the skin, to the more temporary building services, space plan and ultimately the scenery / stuff that fills the space. We transpose this method of analysis to the consideration of urban space and add a time-dimension, in the form of ‘rate of change’ parametric or renewal, to the different layers of site, services, surfaces, signs, and surroundings within the public realm.

We present a series of city centre case studies that map a variety of squares and streets, using an ‘object-orientated’ approach to recording the ‘rates of change’ ranging from constant, hourly, daily, monthly, yearly through to renewal over decades and centuries. While it was initially intended as a thought experiment relating to society, the idea of long-term thinking is a beneficial tool for urban designers and planners. As such, the experimental output is presented dynamically, as layered chronological map progression supported by mixed archival secondary sources and primary data gathered using remote sensing and other photographic evidence. The object-orientated framework provides the basis for analysis and identification of the specific agents responsible for governance and change within the built environment and public realm. We demonstrate how such a visual representation of ‘long-life’ permanency and ‘loose-fit’ temporality can influence the underlying power structures and decision-making in urban planning and management.