Porosity and fragmentation of the block in the city core: a Nolli’s innovation perspective

Urban centrality demands building space that erodes and implodes blocks in the most accessible places. Nolli’s map made in 1748 was the first known graphic reference that visualised the phenomenon. The map and its contemporary interpretation are the starting point for this paper. The research has graphic support from existing maps that used Nolli’s idea to represent those cities, and other maps created <i>ad hoc</i>. It is argued how territories are divided into small units that fold and wrinkle, drawing the conclusion that they do it to (i) find the maximum useful surface area in the minimum amount of space; (ii) concentrate activity; (iii) enable interaction; (iv) optimise resources; (v) accelerate processes; and (vi) cure urban diseases. Methodologically, this is done in two large sections, one showing erosion, division and fragmentation of the central urban layouts, and another emphasising the importance of architecture extending urban layouts to other directions.