Map Symbols and the Legend
A map cannot draw a church at actual size, so it draws a mark instead. The legend is the dictionary that turns those marks back into real things.
Why maps use symbols at all
On a 1:50,000 map, a house measuring ten metres across would be a fifth of a millimetre wide. You could not see it, let alone print it. So maps substitute: a small square for a building, a line of a particular colour for a road, a patch of green for woodland. The symbol is deliberately bigger than the thing it represents, and that is a feature rather than a flaw.
The consequence is that a map is not a shrunken photograph. It is a set of decisions about what matters enough to draw. The legend is where those decisions are written down, which is why it is the first thing worth reading on any unfamiliar map.
Three families of symbol
Almost every symbol you will meet is one of three kinds, and recognising which kind you are looking at tells you how to read it.
Point symbols mark a single location: a church, a viewpoint, a station, a summit. Line symbols follow something long and thin: roads, rivers, railways, footpaths, boundaries. Area symbols fill a region: woodland, water, built-up land, marsh. Point symbols are usually not to scale, line symbols are usually to scale along their length but not across their width, and area symbols are usually to scale in both directions.
Colour does a lot of the work
Before you read a single symbol, the colours have already told you most of the story. The conventions are close to universal on topographic maps, even across countries that disagree about the symbols themselves.
Blue is water. Green is vegetation. Brown is relief, which means contours and anything to do with the shape of the ground. Black is usually built by people and permanent, such as buildings, boundaries and railways. Red or orange is roads, with the brighter shades meaning the bigger roads. Grey or pink shading is a built-up area.
What the colours usually mean
Not a standard exactly, but consistent enough to rely on as a first guess.
| Colour | Usually means | Examples |
|---|---|---|
| Blue | Water | Rivers, lakes, coastline, marsh |
| Green | Vegetation and access | Woodland, parks, public footpaths |
| Brown | The shape of the ground | Contour lines, cliffs, spot heights |
| Black | Built and permanent | Buildings, railways, boundaries, place names |
| Red or orange | Roads | Motorways, main roads, minor roads |
| Grey or pink | Built-up areas | Towns, cities, industrial land |
On a road atlas the same colours mean different things, because the purpose of the map is different. Always check the legend.
How to read an unfamiliar legend quickly
You do not need to memorise a legend. You need to know how to interrogate one.
- Find it The legend is almost always in a margin, a corner, or on the reverse of a folded map.
- Scan the colours first Work out what blue, green and brown are doing on this particular map before looking at individual marks.
- Find the roads Road classifications tell you the map's purpose and how much detail to expect elsewhere.
- Look up only what you see Read the legend entries for the symbols actually present in the area you care about, not the whole list.
- Check the scale and the contour interval They are usually printed next to the legend, and both change how you interpret everything else.
Check what you learned
Five questions on symbols and legends. Pass at 70% or better to complete the lesson.
Practice with Games
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Map symbols, in one paragraph
Map symbols are marks that stand in for real features, because at normal map scales most things are far too small to draw at their true size. They come in three families: point symbols for single locations such as churches and viewpoints, line symbols for long features such as roads, rivers and paths, and area symbols for regions such as woodland and water. Colour carries much of the meaning before you read any individual mark, with blue for water, green for vegetation, brown for relief and contours, black for permanent built features, and red or orange for roads. The legend, sometimes called the key, is where a map defines its own symbols, and it is worth reading first because symbol sets are not international: Ordnance Survey, USGS, IGN and Swisstopo maps all use different conventions.
Common questions about map symbols
What is the difference between a legend and a key?
Nothing. They are two words for the same panel, the part of the map that lists each symbol and says what it represents. "Legend" is more common on topographic maps and "key" in school textbooks, but they mean the same thing.
What do the colours on a map mean?
On topographic maps, blue is water, green is vegetation, brown is relief such as contour lines, black is permanent built features like buildings and railways, and red or orange marks roads. These are conventions rather than a formal standard, and they change on maps with a different purpose, such as road atlases or nautical charts.
Why are roads drawn so wide on maps?
Because drawing them to scale would make them invisible. At 1:50,000 a ten-metre road would be a fifth of a millimetre wide. Line and point symbols are deliberately oversized so they can be seen, which means their position is accurate but their width is not.
Are map symbols the same everywhere in the world?
No. Each national mapping agency has its own symbol set, and they differ significantly. A green dashed line means a public right of way on a British Ordnance Survey map, but carries no such meaning on a French or American map. Always read the legend of the map in front of you.
What do the three kinds of map symbol represent?
Point symbols mark a single spot, such as a church, summit or viewpoint. Line symbols follow something long and thin, such as a road, river or boundary. Area symbols fill a region, such as woodland, a lake or a built-up area. Recognising which kind you are looking at tells you how literally to read its size.