A route choice is a comparison: length against gradient, with landforms as extra evidence. Write what you can see on the map, then what it means for travel.
This lesson is part of contours, height and cross-sections. It uses gradient from inferring slope steepness from contour spacing.
What should a route answer contain?
Include four things: the length of each route, the height gained, the gradient, and one landform or feature that affects the journey. Then state which route suits the stated need.
The need matters. A walker carrying books wants a gentle slope, whereas a cyclist wanting speed might accept a steeper one.
Worked example
This is a worked example. A villager walks from a village at 40 m to a school at 100 m. Route 1 is direct, 2.4 km long. Route 2 curves around the hill and is 4.0 km long.
| Measure | Route 1 | Route 2 |
|---|---|---|
| Length | 2 400 m | 4 000 m |
| Height gained | 60 m | 60 m |
| Average gradient | 60 ÷ 2 400 = 1 in 40 | 60 ÷ 4 000 = 1 in 67 |
| Landform crossed | A steep spur near the school | A valley floor along a stream |
Both routes rise 60 m, since 100 − 40 = 60. Route 1 climbs more steeply. It saves 4 000 − 2 400 = 1 600 m of walking.
Written answer for a walker carrying heavy books. “Route 1 is shorter by 1 600 m, whereas Route 2 has a gentler average gradient of 1 in 67 against 1 in 40. Route 1 also crosses a steep spur near the school, so the last part may be tiring. For a walker carrying books, Route 2 is better, although the map does not show whether the valley floor floods after rain.”
The mistake: using length alone
A weak answer reads: “Route 1 is better because it is shorter.” It ignores the contours entirely, which is the reason the question supplied a contour map.
| Weak | Strong |
|---|---|
| “Route 1 is shorter.” | “Route 1 is 1 600 m shorter but rises at 1 in 40.” |
| “Route 2 is longer.” | “Route 2 is longer but has a gentler 1 in 67 gradient.” |
| “Route 2 is best.” | “Route 2 suits a walker who wants less climbing, although flooding in the valley is not shown on the map.” |
Notice the strong answer names the need and one unknown. The unknown keeps the claim honest.
Check yourself
Route A is 1.8 km long and climbs 45 m. Route B is 3.0 km long and climbs 45 m. Calculate each average gradient and say which is gentler.
Answer
Route A: 45 ÷ 1 800 = 0.025, which is 1 in 40.
Route B: 45 ÷ 3 000 = 0.015, which is 1 in 67.
Route B has the gentler gradient, although it is 1 200 m longer (3 000 − 1 800). Which route is better depends on whether the traveller values a short journey or an easier climb.
What to study next
Test all four contour skills together in the contours practice set. If your gradients are shaky, redo inferring slope steepness from contour spacing.
The graph evidence and fair-comparison lab helps you practise fair comparison. For a teacher to read your answers, see online one-to-one Geography tuition.