OS Map Symbols
Cartographers have always looked for the easiest and most obvious solutions to the challenges of providing vast quantities of information clearly and concisely on their maps. The first Ordnance Survey maps widely available were printed in monochrome, and so the problems were perhaps more challenging than on our modern technicolour maps. However, the range of information was substantially less. Below is an overview of the various symbol types that have been used since those early black and white sheets to the present day.
Work in Progress Using OS six inch (on NLS Maps layer); One Inch / 7th series and modern OS as basic sources.
Contours and hills
Early maps often failed to show hills with any accuracy, at best they were shaded, to show their shape, based on the sun being in a fixed position relative to the map, and casting different shadows over the slopes. Later, contour lines were introduced, following as closely as possible the curvature of the hill. Initially there were shown by dot-dash lines, interrupted in places by the height, in feet. when colour was introduced, various shades of brown have been used to show the contours, and on smaller scale maps a variation of shading is also used. This doesn't use the sun as a reference, but rather like Atlases, it uses gradiated colours to depict the height above sea level.
Rivers and lakes
Water was originally depicted in a manner hardly distinguishable from roads, albeit the name of the water course and direction of flow were indicated. Since coloured maps were introduced, rivers and lakes have been shown in Blue, often blue boundaries with a stippled blue fill for rivers and lakes, whilst streams are just a narrow solid blue line.
Early maps depicted woodland with pictures of trees, although there was no clear differentiation between natural woodland and forestry plantations. Today, most OS maps depict whether it is a patch of deciduous, mixed or coniferous trees. The symbols for moorland or heath have hardly changed, being a series of dots/dashes in the shape of a tuft of grass.
Buildings and Urban areas
The use of solid black for urban areas on early coloured maps had the advantage of making the streets stand out, but conversely it made it near impossible to provide any written information. The 7th series sheets moved over to a stippled grey with black outlines, and modern mapping uses an even friendlier stippled orange colour.
In rural areas, single buildings were shown as black boxes even after urban areas were coloured differently. However, they are now coloured in the same way as larger urban areas.
OS maps have long since included symbols for a selection of useful buildings, such as churches (more recently generalised as places of worship); Post Offices, Town Halls and Schools. Their inclusion can be hit and miss, being less common in dense urban areas where other mapping requirements take precedence.
Originally roads were simply depicted by two parallel lines, with one slightly heavier than the other. If the road is not fenced, then the line is dashed. Later, when colour was introduced, roads were coloured according to standard, so the best roads were Red, average roads a yellow-orange, and poor or narrow roads left white. These colours have survived to the present, with red commonly used for A roads, orange or brown for B roads, Yellow for unclassified and white for urban streets and country lanes. When Motorways were built they were initially coloured red, but quickly changed to blue, using a similar shade to the signage, to help differentiate these new routes. More recently, green has been introduced for primary routes, again matching the signage colour.
Showing roads on maps is not just about what type of road you are looking at, but also about how a road interacts with the landscape, whether natural or man-made. As such, there are a range of structures and other features which are found on roads, the following being commonly shown on OS maps. Many of these symbols remain unchanged from the first colour one inch series.
Railways are typically depicted by either a solid black line (2 or more parallel tracks), a black/white dashed line with black outline (single tracks) and narrow black line with cross bars, a very literal representation of the physical tracks for sidings and narrow gauge lines. Older maps used a similar symbol without differentiation.
Places of interest
Places of interest and tourist destinations have become increasingly important on OS maps in the last 50 or so years, indeed their inclusion is often a main selling point.