Geography Reference
In-Depth Information
60
2000 R
2
=
0,66
55
50
45
40
35
1970 R
2
= 0,51
30
25
20
0
1,000
2,000
3,000
4,000
5,000
Metropolitan population (square root)
POP_2000
POP_1970
Linear regression (POP_1970)
Linear regression (POP_2000)
Figure 7.1.
Urban sprawl in major cities, 1970-2000
Equation [7.1] determines the linear relationship between size (measured by the
square root of the total population) and sprawl (measured by the standard distance in
kilometers) of the 20 major US cities in 1970. The correlation coefficient is
r = +0.72
,
which means that most of the variation of standard distance in 1970 is directly
proportional to the square root of the metropolitan population.
DS
e
6
e
3
POP
22
,
502
.
[7.1]
For 2000, equation [7.2] expresses a general intensification of the linear
relationship. The highest slope, 8 instead of 6.1, shows that the sprawl is growing
with a constant population and the correlation coefficient is now
r = +0.81
, which
means that city profiles have been standardized. Two-thirds of the variation of
standard distance in 2000 is directly proportional to the square root of the
metropolitan population.
DS
e
8
e
3
POP
19
,
06
.
[7.2]
Given this relationship between the size of a city and how widespread its
population is, and considering various indicators such as density and speed of this
expansion, we come to understand that every major US city spread more in the last
three decades of the 20th century. However, the speed and extent of sprawl varied
from city to city.
