THE URBAN SYSTEMTHE URBAN SYSTEMCENTRAL PLACE THEORY and RELATED CONCEPTS

THE US AT NIGHT

IS THERE AN ORDER TO THIS?Maybe it ’s an underlying geometry in the sett lement pattern…

IS THERE AN ORDER TO THIS?Maybe all we need to do is rearrange the cit ies slightly to make the pattern apparent.

OBJECTIVE

• to understand the dynamics shaping the urban hierarchy

• what makes cities grow quickly or slowly?

• how do urban settlements of a particular size affect the

emergence and growth of other settlements of the same or

different size?

• what pattern would the system of settlements form in the

absence of complicating factors such as topography and

history?

WHY ASK THESE QUESTIONS?• to advance toward a more scientific understanding of

urbanization

• to develop a foundation on which to build a positivist theory of urban growth

• to “raise” urban studies to the “level” of the hard sciences--assuming the hard sciences are superior to the soft (humanistic, descriptive, probabilistic) sciences

EVERY SCIENCE NEEDS A FORCE …• economic competition• between cities

• rational maximization• by individuals

• friction of distance as a driving force• cost distance• time distance• (later) cognitive distance

IN SHORT…

• Through rationally maximizing the productivity of their time…• by minimizing the costs of various activities measured in

money and time,• people collectively create a system in which facilities of all

sorts…• including cities,

• are pitted against each other…• and all facilities emerge from this competition in

advantageous locations and with predictable-sized areas of dominance.

COMPETITION PRODUCES ORDER

In other words …

FOUNDERS OF CENTRAL PLACE THEORY

•C.J. Galpin (1915)• sociologist studying rural communities in Wisconsin• decided that under ideal conditions settlements

would be spaced evenly• pattern: overlapping circular service areas with the

central places aligned in a hexagonal array• overlap of service areas indicates a region in which a

person is equally inclined to shop at either central place

GALPIN’S MODEL

FOUNDERS OF CENTRAL PLACE THEORY

•Walter Christaller (1966)• assumption: each good has its particular

range and threshold • threshold of a good: minimum size of market

capable of sustaining a business devoted to that good• range of a good: maximum distance a person

will be willing to travel to obtain that good• associated assumptions• variations in range and threshold from person

to person or from culture group to culture group are irrelevant• most people will shop at only one center

DETAILS OF CHRISTALLER’S THEORY

• The vast range of retail functions could be grouped into 7 “orders,” corresponding to cities with different sized hinterlands• the functions in an order share a similar threshold and

range• automobiles would be in a different order than loaves of

bread, for example•What might be in the same order as automobiles?•What might be in the same order as loaves of bread?

HYPOTHETICAL PATTERN OF CENTRAL PLACES

MORE TERMINOLOGY

• “Higher order” goods and services are those with a wider range and higher threshold, located in larger urban centers• “Lower order” goods and services are those with a

narrower range and lower threshold, located in smaller urban centers• “break point”: the invisible boundary between markets of

competing central places• “isotropic plain” uniform land surface on which these

ordering principles would generate a hexagonal pattern of cities

AN INTERPRETATION OF THE URBAN HIERARCHY (LISTED BY ORDER)

1. largest cities (all functions, highest to lowest)2. large cities 3. small cities 4. larger towns 5. smaller towns 6. villages 7. hamlets (only the lowest order functions)

VARIATIONS ON THE BASIC THEORY

• different patterns result from different values of k•market optimizing, k=3 (minimizes total number of

settlements serving a region)• traffic optimizing, k=4 (emerges by minimizing the road

lengths joining all adjacent centers)• administration optimizing, k=7 (assumes lower-order

places must be contained in the administrative districts of higher order places; can not be situated on the breakpoint)

MARKET PRINCIPLE (A) AND TRANSPORTATION PRINCIPLE (B)

Market principle

Transport principle

Administrative principle

ADVANTAGE OF CENTRAL PLACE THEORY

• Central place theory has a number of advantages. It allows

us to see how and why two places differ, and how and why

places differs from the model

• In very flat areas and in primitive societies, central place

theory has been fond to approximate reality.

• It has also been used extensively in rural planning, especially

in the key settlements plans

CRITICISMS OF CENTRAL PLACE THEORY

• Isotropic plains do not exist• People are not rational. Even using the limited assumptions

of the model there is preference in terms of shopping, and increasingly, there is bulk shopping. Time or cost may be a more useful measure than distance• It is static and there is no explanation of how patterns

change • It does not take into account specialty towns such as tourist

town• In man cases chance has played a part in determining

settlement pattern. The model does not allow for this.

WHAT WOULD THIS INDICATE?

• Urban hierarchy’s regularity may not be caused by the random perturbation of what would ideally be a step-wise function caused by competition between cities

• Instead, it may be caused by the natural emergence of dominant (hub) nodes within a dynamic network