The Dictionary of Human Geography

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multiple nuclei model A model of intra-

urban land-use patterns developed by Chauncy

Harris (1914–2003) and Edward Ullman

(1912–76: see Harris and Ullman, 1945) that

combines and extends the features of the earlier

zonal modelsandsectoral modelsof the

chicago school. Rather than being based on

a mono-nuclear city, this model has land-use

patterns organized around several nodes (see

figure), on the argument that different uses

cluster together (in some cases to share special-

ized facilities) and wish to avoid other uses,

thereby creating a number of nuclei around

which the city is organized. rj

Suggested reading

Harris (1997).

multipliers A measure of the total economic

impact of an investment decision, policy

change or external ‘shock’. This includes not

just the initial, immediate impact, but also the

indirect or ‘knock-on’ consequences. Thus a

new manufacturing plant creates initial employ-

ment; this creates a demand for services in the

locality,sotriggeringothernewjobs.Themanu-

facturing expansion also generates demand for

additional inputs of energy and steel, so having

ripple effects on supplying sectors. Such multi-

plier effects can be traced usinginput__output

models. There is also a need to track the geog-

raphy of these multiplier effects, to see what

‘leaks’ from the local economy into other

regions, and estimating spatial multipliers

undertaken inspatial econometrics. lwh

Suggested reading

Anselin (2003); Smith (1981).

music Althoughgeographyhas often been

dominated by visual means ofrepresenta-

tion, the study of music, and indeed sound

more generally, has a long if discontinuous

history within the discipline. The earliest

multiple nuclei model Generalization of the internal structure of cities. The concentric-zone theory is a

generalization for all cities. The arrangement of the sectors in the sector theory varies from city to city. The diagram for

multiple nuclei represents one possible pattern among innumerable variations(Harris and Ullman, 1959)

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MULTIPLE NUCLEI MODEL