Multiple Nuclei Theory
This theory was first proposed in 1945 by Harris and Ullman. They constructed this model to demonstrate that not all cities fit into the concentric and sector model. They claimed that although these patterns may exist, reality is far more complex than those two theories imply. They argued that land use patterns do not grow from a single central point in the city but from multiple points or nuclei. They assumed more than one desired location for access. This is based on the fact that many towns and nearly all large cities grow about many nuclei rather than around a simple CBD. Some of these nuclei are pre-existing settlements; others arise from urbanization and external economies. The number and functions of the nuclei differ from city to city.
