3. Rank Size Rule
This
is an attempt to find a numerical
relationship between population size
of settlements within an area such as
a country or county
Settlements are ranked in
descending order of population size,
with the largest city first
4. Assumptions
The
2nd ranked city will have 1/2 the
population of the 1st
The 3rd ranked city will have 1/3
population of the 1st
The 4th ranked city will have a ¼
population of the 1st ranked city
5. Example
The
largest city has a population of
1,000,000
The 2nd largest city: 1,000,000/2=
500,000
The 3rd city: 1,000,000/3= 333,333
The 4th city: 1,000,000/4= 250,000
And so on….
6. Formula
This allows us to express the rank size rule
as:
Pn= Pl /n (or R)
Pn= The population of the City
Pl= The population of the largest city
N (or R)= The rank size of the city
See graph Page 404/405 Brazil e.g.
7. Variations from the Rank Size Rule
It
is rare to find a close correlation
between the city size of a country
and the rank size rule
8. Primate City
This
is found where the largest city
(often the capital) completely
dominates a country or region
The population size will be many
times greater than that of the 2nd or
3rd city
9. Example of Primate City: Buenos
Aires
Populations
in thousands:
Buenos Aires: 10,990
Cordoba:
1198
Rosario:
1096
Mendoza:
775
La Plata:
640
San Miguel de Tucuman: 622
10. Binary Distribution
Occurs
where there are 2 very large
cities of almost equal size within the
same country. One may be the
capital and the other a major port or
industrial centre
Examples: Spain- Barcelona and
Madrid
11. Exceptions to the rule
Rank size rule is more likely to operate in
a country that is developed or urbanised
for a long time
Large in size
Stable economic and political organisation
Primate distribution is likely to occur in
countries that are small, less developed
and only recently urbanised