Map Scales

Map Scales

Maps are drawn to scale, but what exactly does that mean?

Map Scales 


Maps are drawn to scale, meaning that there is a uniform measure between a distance on the ground and an equivalent on the map. This is referred to as ‘The Scale’, and is a numerical representation of one unit on the map representing X thousand of the same unit on the ground. These days in the UK all maps are metric, with one of the most common scales being 1:25,000. What that means in practice is that 1cm on the map equals 25,000 cm on the ground, or 250 metres (one km being equivalent to 1,000 metres, with there being 100,000 cm in one km). 

Another common scale of walking map is 1:50,000, with road atlases – being maps too – having a scale of around 1;200,000.

The scale of a map is important, and is typically shown on the outside cover and on the legend.

For walking, the more detailed map or the two Ordnance Survey type maps, is the 1:25,000 as it shows field boundaries and Open Access Areas in England & Wales

Large and Small Scale Maps

You may hear of people referring to ‘large scale’ or ‘small scale’ maps, and the term can be a bit confusing. The fewer cm that are in the scale means that there is more detail on the map, and typically maps with a number of 1:50,000 or smaller are referred to as Large scale maps, with 1:10,000 sometimes being produced for some complex mountain ridges. 1:25,000 and 1:50,000 are the most common, but Harveys Maps also produce a 1:40,000 version, which is a half way house between the two. A road atlas would be classed as an intermediate or small scale map, as such a map would have a scale of about 1:200,000.

The definition of 'large' relates to the fractional part if you divided 1 by, say, 25,000 (as in 1:25,000). The result of that calculation is that one 25,000th is bigger than one 200,000th of one. Thus, the smaller the headline number the larger the scale!


Here's a video that gives an explanation of map scales

Ordnance Survey MapZone

Ordnance Survey have put together an interactive guide relating to Scale 

Ordnance Survey MapZone