Natural features and heights - OS 25K symbols

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This is one of a series of articles which give photographs of features on the ground which have standard symbols on Ordnance Survey 1:25,000 maps, and also show the symbol. See OS 25K map symbols for introduction to the series, and links to other articles in it. Ordnance Survey have told us that although the symbols are copyright they allow them to be copied without charge or specific licence.

Click on a photo thumbnail to see a page with a larger photo, and other photo details (in a new window). The photo page also has a section of the 1:50,000 Ordnance Survey map; click on that map to see an Ordnance Survey Get-a-map section of 1:25,000 scale map.

Note that the Get-a-map links in the notes column do not open a new window; use the browser back button to return to this article.

Heights and contours

Description	Symbol	Photo	Notes
Ground survey height			Map link There is an 1141 metre spot height
Trig pillar height			Map link If one height is shown by a trig pillar symbol, it is that of the base of the trig pillar. If a second is shown in brackets it is that of the highest point of the hill.
Air survey height			Map link
Contours at 5 metre intervals			Map link
Contours at 10 metre intervals			Map link
5 metre interval contour stopping at grid line			Map link Use of 10 metre intervals between contours is by discrete areas. Some paper Explorer maps specify in the key that all contours are at 5 metre intervals, some sheets all at 10 metre. In the example shown here the interval changes south of the grid line at NY150500, and the 15 and 25 metre contours stop at that line.
Contours merge at steep face			Map link
Contours band together at cliff			Map link The OS symbol key indicates that as contour lines get closer they merge to have just a single contour line at a cliff. In practice it seems that there is a wider contour line, as along these vertical cliffs on Anglesey

Rock features

Description	Symbol	Photo	Notes
Loose rocks			Map link
Boulders			Map link Most items called boulders by photographers have map symbols which are dots or very small circles; it is difficult to distinguish loose rocks from boulders.
Outcrop			Map link
Scree			Map link

Note that the colour of rock features is being changed from black to grey - below are black versions:

Below are grey versions:

Water, mud, sand and shingle

Description	Symbol	Photo	Notes
Water			Map link
Water (narrow)			Map link The symbols key for 25K maps does not have a "water features" section. Drains, rivers, canals and the sea are all shown by the blue colour. Watery words like spring and well and the names of water features also appear in blue.
Mud			Map link
Sand			Map link
Sand and shingle			Map link

Map symbol images are Crown Copyright.

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