Why Do Maps Use Symbols?
Maps represent large areas on a small piece of paper. There is not enough space to draw everything in detail, so symbols are used instead of words or realistic drawings. A symbol is a shape, colour, or pattern that stands for a real feature.
Common Map Symbols
Different symbols represent different features:
| Symbol type | What it represents |
|---|---|
| Blue lines | Rivers and streams |
| Blue filled area | Lakes and reservoirs |
| Dotted line | Footpath |
| Dashed line | Bridleway or track |
| Black solid line | Road |
| Green area | Woodland or forest |
| Black crosses | Church |
| P with a box | Car park |
| Triangle | Triangulation pillar (hilltop) |
Ordnance Survey (OS) maps in the UK follow a standard set of symbols, so once you learn them, you can read any OS map.
Colours on Maps
Colours also carry meaning:
- Blue — water features
- Green — vegetation, parks, woods
- Brown contour lines — shape of the land (hills and valleys)
- Yellow/orange — roads
- White — open land or urban areas
Contour Lines
Contour lines are brown lines that join places at the same height above sea level. Closely spaced contours mean a steep slope; widely spaced contours mean a gentle slope.
Real world: Using OS maps for hiking in the UK
The Ordnance Survey (OS) produces detailed 1:25,000 and 1:50,000 maps of all of Great Britain. Walkers on the Pennine Way (a 431 km national trail from Derbyshire to Scotland) rely on OS Explorer maps to navigate moorland, avoid bogs, and find overnight accommodation. Each OS map uses standardised symbols — yellow dots for access land, blue for rivers, brown contour lines for hills — allowing anyone who has learned the key to navigate safely. Mountain Rescue teams credit map-reading skills as one of the most important safety competencies for outdoor activities.
Real world: Satellite navigation vs. paper maps
Modern GPS navigation apps (Google Maps, Waze) have largely replaced paper maps for driving, but understanding map symbols remains essential in many contexts. Emergency services, military personnel, and geologists all still use paper maps because GPS satellites can fail, batteries die, and digital maps lack the detail of specialist topographic surveys. During the 2021 Tonga volcanic eruption, satellite links were cut — recovery teams used paper navigational charts to coordinate relief efforts when digital systems were unavailable.
Real world: Urban planners reading land use maps
Town and urban planners use specialised land use maps to decide where to build housing, schools, and roads. In the UK, Ordnance Survey's MasterMap dataset assigns every piece of land a category (residential, commercial, greenspace, water). A developer proposing a new housing estate must consult these maps to check whether land is a floodplain (blue area), ancient woodland (green), or brownfield site. Misreading or ignoring map data has led to costly planning disasters — including houses built on floodplains that flood regularly.
Where do you see this in real life? Next time you use Google Maps or a hiking app, notice that the colours and symbols follow many of the same conventions as paper maps — blue for water, green for parks, brown for contours in terrain view. Digital maps use the same language of symbols that cartographers developed over centuries.
Practice Problems
What does it mean on a map if contour lines are very close together?
Show answer
Why is the map key (legend) important when reading an unfamiliar map?