The concentric zone model, also known as the Burgess model or the CCD model, is one of the earliest theoretical models to explain urban social structures. It was created by sociologist Ernest Burgess in 1925.Based on human ecology theory done by Burgess and applied on Chicago, it was the first to give the explanation of distribution of social groups within urban areas. This concentric ring model depicts urban land usage in concentric rings: the Central Business District (or CBD) was in the middle of the model, and the city expanded in rings with different land uses.
Concentric zone model
Commuter zone
Residential zone
Working class zone
Zone of transition
Factory zone
Central business district
The sector model, also known as the Hoyt model, is a model of urban land use proposed in 1939 by economist Homer Hoyt. It is a modification of the concentric zone model of city development. The benefits of the application of this model include the fact it allows for an outward progression of growth.
The model describes the layout of a city, based on Chicago. It says that even though a city may have begun with a central business district, or CBD, other smaller CBDs develop on the outskirts of the city near the more valuable housing areas to allow shorter commutes from the outskirts of the city. This creates nodes or nuclei in other parts of the city besides the CBD thus the name multiple nuclei model. Their aim was to produce a more realistic, if more complicated, model.