Maps use symbols to label real-life features and make the maps clearer. With so many features on a map, there would not be enough space to label everything with text. Symbols can be small pictures, letters, lines or coloured areas to show features like campsites, pubs or bus stations.
To find out how close your drawings are to actual Ordnance Survey symbols you can look at the key on an Ordnance Survey map. Maps will usually have a key or a legend. This is a section that will explain what each and every symbol on the map represents.
Chisel Cut (Mark)
You'll never mistake them for a water feature: the symbol is a blue triangle with a dot in the middle. Rivers do not flow in small triangles.
parish boundariesBoundary stones These usually still mark modern parish boundaries – look to see if there are grey dashed lines on the map that run up to and away from the stone. On the stone itself, look for initials that indicate which parish boundaries are marked by the stone.
Traffic free off-road cycle route On 1:25000 Explorer mapping, off-road cycle routes are depicted with orange dots (provided they're not coincident with a road, bridleway, permissive bridleway, byway open to all traffic or restricted byway).
On weather maps, these readings are represented as a blue “H” for high pressure or a red “L” for low pressure.
Many think it is War Office-related, but it is in fact an OS benchmark (BM) and a means of marking a height above sea level. Surveyors in our history made these marks to record height above Ordnance Datum Newlyn (ODN – mean sea level determined at Newlyn in Cornwall).
The colors of the lines usually indicate similar classes of information: topographic contours (brown); lakes, streams, irrigation ditches, and other hydrographic features (blue); land grids and important roads (red); and other roads and trails, railroads, boundaries, and other cultural features (black).