Urban growth can be measured inside the city boundary or across the wider metro area. The two figures can differ a lot, so always check which one a question uses.
This lesson belongs to settlements and urbanisation. It follows classifying a settlement function.
What is the difference between the two?
The boundary is a legal line. The metro area is a pattern of built-up land and daily travel that can cross that line.
Ask of every figure: “Which line is this counting inside?” The answer decides which growth you can talk about.
Worked example: City Kota Bayu
Here is an original city. In 2000, City Kota Bayu has 300 000 residents inside its boundary. Its metro area, which includes two neighbouring districts, has 450 000. In 2020 the city has 400 000 and the metro area has 650 000.
- City boundary growth: (400 000 − 300 000) ÷ 300 000 × 100 = 33%.
- Metro area growth: (650 000 − 450 000) ÷ 450 000 × 100 = 44%.
The metro area grew faster. The two neighbouring districts rose from 150 000 to 250 000, which suggests housing spread across the boundary into land that is cheaper or available.
The mistake that costs marks
The common slip is to read the city figure alone and write that urbanisation slowed.
- Wrong: “Kota Bayu grew only 33%, so urban growth is slowing.”
- Right: “The city boundary grew 33%, but the metro area grew 44%, which suggests growth is spilling into neighbouring districts.”
A second slip is to credit migration when the boundary moved. Town T had 80 000 residents in 2010 and 110 000 in 2020, a gain of 30 000, or 37.5%. Yet 20 000 of those people live in villages added by a boundary extension. The real growth is 10 000, or 12.5%.
Check yourself
City Q has 500 000 residents in its boundary in 2010 and 560 000 in 2020. Its metro area rises from 800 000 to 1 000 000. Compare the two growth rates and say what they suggest.
Answer
City: 60 000 ÷ 500 000 × 100 = 12%. Metro area: 200 000 ÷ 800 000 × 100 = 25%.
The metro area grew about twice as fast, which suggests most of the growth happens in suburbs outside the city boundary.
What to study next
Growth puts pressure on particular services. Continue with tracing an urbanisation effect through a specific service demand, then use the graph evidence and fair-comparison lab to test comparisons.
If you want a teacher to check your growth wording, see online one-to-one Geography tuition.