Map Scales Explained

by | Feb 2, 2025 | Map Production

Maps are a scaled down version of an area they represent. Map scale is the ratio of an actual distance on the ground compared to the same distance on a map.

The three most common types of map scales are ratio (also called numerical or fractional), graphic, and verbal (also called simple). Gem Trek uses both ratio and graphic types on all our maps.

Ratio Scale

A ratio scale is shown as a ratio of two numbers, with 1 on the map representing multiples of the same distance on the ground.

A Gem Trek hiking map with a scale of 1:50,000 indicates that one unit (centimetre or inch, for example), represents a 50,000 multiple of that same unit on the ground. So in this example, one cm on our map represents 50,000 cm out in the field. To make the correlation easier to understand, convert the on the ground measurement to a more appropriate unit of size. So in this example, 1 cm on the map would equal 500 metres on the ground.

Graphic scale

A ratio scale can’t be read directly as a comparison on the map. Sop we add a graphic scale. The graphic scale is indicated on a ruler drawn on the map. It shows values from 0 to the actual distance. On a Gem Trek map with a 1:50,000 scale, 2 cm on the map equals 1 km on the ground.

graphic map scale

Measuring actual distances on a map

To measure exact distances on a map using the ratio scale, follow these steps:

  1. Measure the distance between two points on the map in centimetres.
  2. Multiple the measured difference with the larger number of the map scale. This will give the distance in centimetres
  3. Divide the distance in centimetres by 100 to convert to metres. You can also then divide the distance in metres by 1,000 to get a distance in kilometres.

For example, on the Gem Trek Waterton Lakes National Park map:

  • The distance from Waterton townsite to the south end of Upper Waterton Lake is 21 cm
  • The map scale is 1:50,000. So 21 x 50,000 = 1,050,000 cm
  • 1,050,000 cm = 10,500 metres or 10.5 km

Therefore, the actual distance on the ground between Waterton townsite and the south end of Upper Waterton Lake is 10.5 km.

Verbal scale

The relationship between a distance on a map and the distance on the ground can also be expressed verbally. For example, 2 cm on the map equals 1 km on the ground. When this is put into writing, it is often called a simple scale: 2 cm = 1 km.

Changing the size of a map

If the size of a printed map is changed, by photocopying for example, the ratio scale becomes false while the graphic scale remains correct.

Small or large scale?

It seems counterintuitive, but the larger the number the smaller the scale! For example, our Canadian Rockies Map (1:400,000) can be described as a smaller scale map while our Banff Up-Close Map (1:35,000), which has much more detail, is a large-scale map.

Select your maps based on the amount of detail you will need.

  • Small scale maps cover a wider surface area, but in less detail. These are our Driving Maps, designed for trip planning.
  • Large scale maps cover smaller surface areas, but in greater detail. These are our Hiking Maps.

The maps below represent the difference between a 1:400,000 scale map and the extra data that is included in a 1:50,000 map.

gem trek map scale

Gem Trek Canadian Rockies Map. Scale 1:400,000

 

Grid lines

Gem Trek hiking maps also include light blue grid lines. These lines represent 1 kilometre on the ground, regardless of the map scale (the distance across a square is approximately 1.5 kilometres).