Choosing a map
Q Is 1:25,000 the most detailed mapping you can get for the UK? Stephen Tyler, via email
Lyle says Everything about map scales sounds confusing and hopefully this answer will make it much simpler. The direct answer to your question is no, 1:25,000 is not the most detailed mapping you can get; larger scale maps are available and some very useful. Larger scale sound confusing? Let’s clear this up now.
The relationship between distance on the ground and distance on the map is known as the scale of the map. It is always expressed by what 1cm on the map represents on the ground. On a 1:50,000 map, 1cm on the map represents 50,000cm on the ground. This sounds confusing, yet if I tell you that every 2cm on this map equals 1km on the ground suddenly it becomes meaningful and useful. On a 1:25 000 map every 4cm equals 1km on the ground, which is why we describe this as a larger scale map than the 1:50,000.
A lot of mountaineers use Harvey’s 1:12,500 Summit maps, where 8cm on this map equals 1km on the ground. With these very large-scale maps you get extra clarity and detail, perfect for dangerous areas such as some mountain summits! Larger still at 1:10,000 Ordnance Survey maps are used by orienteers, with some clubs even using OS 1:5,000 maps!
OS maps of the same area at different scales (l to r) 1:25,000, 1:10,000 and 1:5,000. All are available from specialist map suppliers online.