Map Scales
The relationship between the size of features on the earth’s surface and the same features
on a map is shown by the map scale. A map is simply a small representation of a larger
area, in the same way that a model airplane is a small representation of the real one.
Methods of Showing Scale
1) Representative Fraction (R.F.) or Ratio Scale
- This scale has no units (usually assume cm) and is written in ratio form
- Example: 1: 50 000
- This ratio is saying that one unit on the map represents 50 000 units on the earth’s
surface.
2) Verbal Scale:
- This scale is given to you as a written word statement.
- Example: 1cm to 10km OR 1cm = 10km
3) Linear Scale:
- This scale uses a line divided into equal parts to give you the scale of the map.
- Example: 0 1 2 3 4cm
0 5 10 15 20km
- This scale reads that 1cm is equal to 5km
Converting Scales
When converting from a ratio scale to a verbal scale, move the decimal spot 5 digits to
the left.
Therefore: 1:50 000 becomes 1cm = 0.5km
When converting from a verbal scale to a ratio scale, move the decimal 5 digits to the
right.
Therefore: 1cm = 10km becomes 1:1 000 000