Field Boundaries

Field Boundaries

A key difference between 1:25,000 and 1:50,000 Ordnance Survey maps, is field boundaries

Field Boundaries 

Field Boundaries

A key difference between Ordnance Survey's 1:25,000 maps and 1:50,000 maps, is the inclusion of more detail on the 1:25,000 versions. Focussing on one important additional piece of information on the 1:25,000 maps, is field boundaries.

The most common form of field boundary is a fence or dry stone wall, but the map symbol also includes other obvious field divides such as a line of trees or ditch. 

From a navigation perspective, field boundaries are dynamite! They are line features and a great way to pin-point your location on the map. In some upland areas of the UK, most notably The Lakes, there are dry stone walls all around. Meaning that in poor visibility on the side of a hill, a fence or wall on the ground will most likely be on your 1:25,000 map.

Example of a Field Boundary

Close to the summit of Scoat Fell in The Lake District, in poor visibility.  

Example Maps

1:25,000 scale map

         1:50,000 scale map


 ©Crown copyright and database rights Ordnance Survey licence number 100054073 2013
The thick red arrow shows the approximate position from which the photo was taken, and the solid black line on the map in front of the arrow is the wall (field boundary), as shown in the photo. Your location can be more certain being next to the line feature, especially as the wall turns a corner on both in reality and on the map. On the 1:50,000 map, the wall is not shown, making it much more difficult to be certain of your position.


The additional line features provided by 1:25,000 maps make them ideal for hill walking in areas such as Snowdonia, The Peak District, Lake District and other areas where the landscape has a quantity of walls and fences. Where the landscape has fewer field boundaries, such as certain areas of the Highlands, the argument for 1;25,000 diminishes, and a 1:50,000 map may be sufficient.