Scales on a map

Of course maps range considerable from a global to a local OS map, but the one thing that they all have in common is a scale.

When scaling down a map, every part of the map is scaled by the same amount. This insures that every object on the map is the same proportion as everything else on the map. If a city is twice as large as a neighboring town, an accurate scaled map will show the same relationship on paper. The drawn city will be twice as large as the drawn town.

A "scale" shows the relationship between a certain distance on the map and the distance on the ground. On a map there is often a 'legend' that provides information on the symbols used and specifies the scale.

The scale can be expressed numerically and/or literally. An example of the former is 1/100,000 or 1:100,000. i.e. one centimeter on the map equals 100,000 centimeters (1 kilometer) on the earth. A word statement gives a written description of map distance, such as "One centimeter equals one kilometer".

A graphic scale does solve this problem because it is simply a line marked with distance on the ground which the map user can use along with a ruler to determine scale on the map.

In terms of teaching this element of scale the students can be provided with a map and asked to work out the distance between a number of points in real terms using the map scale. Also they can then look at the results on Google earth so that they can 'see' the distance for themselves.