Notes

The multiple nuclei model (left image) is an alternative way of understanding the urban spatial structure of North American cities, it was proposed in 1945 by two geographers Chauncy Harris and Edward Ulliman.
These geographers noticed that cities often had multiple cores rather than a single core.
What the core was varied from city to city but mostly consisted of a harbor area, government distract, university, or manufacturing areas.
These multiple nuclei models influenced the patterns of land use in the city we see today.
In 1964 geographer James Vance developed the urban realms model
The urban realms model was largely based on his observations of San Francisco
He observed that suburbs had become self-sufficient and all had become their own urban realm or independent entity
Vance’s model recognizes the importance of automobile in evolution of the spatial form of cities
This model also acknowledges that these suburban downtowns frequently rival traditional CBD for commercial and retail trade