- Define and explain OS Map Symbols in your own words
- Use key terms such as eastings accurately
- Apply what you have learned to new examples and questions
- Avoid the common mistakes learners make with this topic
Ordnance Survey maps are packed with information — if you know how to read them. In this chapter you will decode OS symbols, master four- and six-figure grid references, and use scale to turn centimetres on the page into kilometres on the ground.
This lesson focuses on OS Map Symbols: recognise common Ordnance Survey symbols for roads, buildings and land use.
Recognise common Ordnance Survey symbols for roads, buildings and land use.
Key ideas
Along the corridor, then up the stairs
Grid references always give eastings first, then northings. Imagine walking along a corridor (across the map) before climbing stairs (up the map). A four-figure reference like 4738 names the 1 km square whose south-west corner is at easting 47 and northing 38.
Six figures give 100-metre precision
To be more precise, divide the 1 km square into tenths. The extra digits estimate how far across and up the square the feature lies — a six-figure reference pinpoints a 100 m by 100 m square. Estimate the third and sixth digits carefully; they are the ones most people get wrong.
Key term — eastings: The vertical grid lines on a map, numbered from west to east — read these first in a grid reference.
A church stands inside the 1 km square with south-west corner 47 east, 38 north. Within the square it sits about three-tenths of the way across and seven-tenths of the way up. What is its six-figure grid reference?
Write the easting of the square's left edge: 47. Add the tenths across: 3, giving 473. Write the northing of the square's bottom edge: 38. Add the tenths up: 7, giving 387. Combine eastings then northings: 473387.
Answer: 473387.
- Writing a four-figure reference when six are needed Four figures only name the whole 1 km square. If the question asks for a specific building, you need the extra precision of six figures.
- Giving northings before eastings It must be eastings first — 'along the corridor, then up the stairs'. Reversing them points to a completely different square.
Practice
Eastings come first, then northings.
A 1 km by 1 km square.
It identifies a 100 m by 100 m square.
1 cm = 500 m, so 6 cm = 3 km.
Quick check
Which of these best defines "eastings"?
Contours on a map are packed very closely together. What does this tell you about the slope?
On a 1:25,000 map, what real distance does 8 cm represent?
- OS Map Symbols: recognise common Ordnance Survey symbols for roads, buildings and land use.
- Along the corridor, then up the stairs: Grid references always give eastings first, then northings.
- northings: The horizontal grid lines on a map, numbered from south to north — read these second.
- Watch out for: writing a four-figure reference when six are needed