Graphs and data presentation in geography
Geography · Key Stage 3 · The School
Matching the chart to the question
A LINE GRAPH shows change over time — rainfall across a year, population over decades — because a line naturally shows a trend rising or falling. A BAR CHART compares separate categories against each other — rainfall in different cities, population in different age groups — because it is easy to compare the height of separate, side-by-side bars.
Pie charts show proportions
A PIE CHART shows how a whole is divided into parts — the proportion of land use types in a region, or the share of energy sources in a country's supply. It answers "what fraction of the whole is this?" well. It is a poor choice for showing change over time, because comparing the size of slices in two separate pie charts is far harder than reading two points on one line.
Scatter graphs show relationships
A SCATTER GRAPH plots two different measurements against each other for the same set of places — rainfall against height above sea level, for instance — to see whether one seems to affect the other. If the points roughly follow a rising line, that suggests a relationship between the two measurements worth investigating further.
A town's population over five decades: 1980 — 12,000. 1990 — 15,000. 2000 — 19,000. 2010 — 24,000. 2020 — 31,000. Drawn as a PIE CHART, each decade becomes a slice of a circle, and a reader has to work hard to see that the town is growing at all, let alone whether growth is speeding up. Drawn as a LINE GRAPH instead, the upward curve is obvious immediately, and it visibly steepens after 2000 — the growth is not just happening, it is accelerating. Same five numbers. One chart type reveals the pattern. The other one buries it.