Geography Reference
In-Depth Information
and a north-south axis from and Michigan to Atlanta. The standard ellipse of
deviation spanned 3 million km² in 1930 and included 74% of the population. In
1970, the same ellipse spanned nearly 4 million km², but included only 71% of the
total population. The US is therefore gradually becoming more polycentric,
particularly through the growth of cities in California, but also of those in the Pacific
Northwest, around the Gulf of Mexico, and Florida. Peripherally situated at the start
of the century, the cities of Denver and Dallas were located in the “heart” of the US
in 1970. While urban growth is widespread, some rural regions are losing
population: the Appalachians, the Cotton Belt of the rural South, and the High
Plains.
1900
1930
1900
1950
1970
1990
2005
1950
1970
1990
2005
1930
Change in density
inh./km
2
0
500
- 23,9 -
0
MSA-CMSA
définition 2000
7 700 000
3 850 000
770 000
-770 000
0
-
10
Pop. Mean Center
Standard Deviation Ellipse
1970
71 %
U.S.
population
Standard Deviation Ellipse
2005
62 %
U.S.
population
10
- 20
20
- 30
30
- 80
80
- 233,2
Method: Quartic Kernel density smoothing in
a flexible bandwidth of the 30 nearest counties
Source: US Census Bureau
Designed and made by JM Zaninetti, University of Orleans, CEDETE Institute
Figure 5.8.
Population growth 1970-2005
