1. Chauncy Harris and Edward Ullman
Multiple Nuclei Model

3. Basic assumptions
More complex urban structures than Burgess and Hoyt’s models
Several independent nuclei
Each nucleus = a growth point and has function different from other nuclei

4. London West End Dockland Westminster: administration
Shopping, entertainment
London
Dockland
Industrial
Westminster: administration

5. Basic assumptions Outward growth of each nucleus
Then they merge as one large urban centre
Barnet and Croydon were towns around London and now become part of greater London.

6. Basic assumptions
If the city becomes too large and congested, some functions may be dispersed to new nuclei.
Dockland industrial decline paves way for the new industries set up near Heathrow Airport, along M25 and M4.

7. Why did Harris & Ullman put forward the model?
Pattern of urban land use does not develop around a single center but around a no. of discrete nuclei.
Some cities have taken up surrounding settlements or have developed strong suburban areas around the periphery of the city.
As the city grows larger, the traditional CBD is no longer sufficient to serve the commercial needs.
As a result, additional nodes emerge in outlying districts such as new suburban shopping center, industrial suburb.

8. Main features of the model
Polycentric / multiple-centred
The model abandoned the CBD as the sole focal point, i.e. suggest alternatively that the zones will develop around a number of quite separate discrete nuclei in addition to the CBD. The number of nuclei depend on the size of the city, i.e. the larger the city, the more numerous and specialized the nuclei are.
The city will develop in a cellular structure in which distinctive forms of land use have developed around certain nuclei within the urban area.

9. Los Angeles

10. Well-established highways

11. Transport junctions

12. Why multi-nuclei?
Different activities have different specific location requirements. Certain specialised functions can only operate where particular facilities are available.
e.g. a CBD locates at the point of maximum accessibility.
e.g. large industries need cheap land.
e.g. high-class housing is drawn to higher parts of a city commanding fresh air and fine views

13. Why multi-nuclei?
Differences in rent-paying abilities —some activities cannot afford the high rents than others.
Manufacturing industry cannot afford the high rents in the inner city and has to locate on cheaper sites.

14. Why multi-nuclei?
Some land uses repel each other e.g. heavy industry is not found close to high class housing.

15. Why multi-nuclei?
Tendency for some kinds of eco. activities to cluster together — some activities locate near other for mutual advantages e.g. shops, enabling customers to compare goods and prices

16. Why multi-nuclei?
Other nuclei develop to aid accessibility around the urban area e.g. develop suburban shopping center to enable people in the suburbs have better access to facilities of the CBD

17. Ikebukuro Ueno Shinjuku Yamanote railway line Roppongi Shibuya Ginza
Shopping and offices
Ueno
Temple town
Shinjuku
Government, office, shopping, entertainment
Yamanote railway line
Roppongi
Parliament, education, entertainment
Shibuya
Shopping, young people entertainment
Ginza
Shopping and entertainment

18. Significance of the model
the most flexible
far more widely applicable to modern large cities

19. Significance of the model
The model matches the dispersal of urban functions with urban sprawl – the dispersal of business activities, retailing activities, residence and manufacturing activities within a large city.
made possible by the mass car ownership and other modern transport facilities.
With increasing urban sprawl, diseconomies set in.
To offset this, the city is disintegreted into a number of nodal regions, each centring on a nucleus which provides many of the functions of the CBD
e.g. Los Angeles with its enormous areal spread and rapid rate of pop. growth, the city is arranged in a multiple-nucleated form.

20. Significance of the model
this model tells more about the concept of agglomeration, forces of attraction and repulsion. These explain the complexity of present day urban functions.

21. Significance of the model
This model does not apply appropriately to each and every city, but rather suggests a no. of general principles which are relevant to the land use pattern of most cities.
It may be taken as a guide to think about the structure of cities rather than a rigid generalization about urban forms