Scale connects a length on the map to a length on the ground. This area covers the four jobs that use it: converting a scale, measuring a winding route, estimating an area and checking units.
It is part of SPM Geography map and graph skills and builds on scale, direction and grid references.
In what order should I study the parts?
Follow this order, since each step uses the one before.
- Converting a representative fraction into a usable distance scale.
- Measuring a winding route without treating it as a straight line.
- Estimating an irregular area with a stated grid method.
- Checking units when converting map measurements to ground quantities.
Each lesson gives one original worked example and one self-check question with an explained answer. Test all four in the cluster practice set.
A short orienting example
On an original map at 1:50 000, a road measures 6 cm. One centimetre stands for 50 000 cm on the ground, which is 500 m. So the road is 6 × 500 m = 3 000 m, or 3 km.
The same 6 cm would be 1.5 km at 1:25 000, because 1 cm is then 250 m. The scale decides everything, so always read it before measuring.
Who should start where?
Start with conversions if you freeze at the ratio. Start with winding routes if straight lines are fine but curves cost marks. Start with units if your method is right and the answers are still marked down.
For a teacher who watches your scale working, see online one-to-one Geography tuition.