figure ground maps

When at a lecture last week given by guest lecturer and architect Emily Crompton I learnt of figure ground maps. This technique of drawing shows how densely built up somewhere is as the buildings are all filled in black. This is the practical use of figure ground diagrams however I find them excellent  visual stimulus as well as informative. 

This plan is for Maine road Manchester from 2004, the plan was to provide a school and shops for the dense population in this area. This can explain the growth of a settled area, once people move  services are provided there, making it yet more appealing to others, and the development of the city goes on.