GeographyMaps: finding anywhere on Earth35 min★★★ difficulty

Grid references and scale on an OS map

Ordnance Survey maps are how Britain finds its way. This lesson teaches six-figure grid references and how to turn centimetres on the map into kilometres on the ground.

Lesson overview

What you'll learn in this lesson

Interpret Ordnance Survey maps, including using grid references, scale, topographical and other thematic mapping, and aerial and satellite photographs

Key learning points

• Four figures first
• Six figures: tenths
• Reading scale
• Measuring a winding route

This lesson at a glance

35 minutes
19 parts to scroll through
4 quick checks
Marked quiz at the end
Gentle pace: short sittings with pauses

Words to know

interpretordnancesurveyreferencestopographical

Scroll down — the lesson carries on below

Part 1 of 19 · Discover5%

Watch & discover

Part 1 of 19

Watch first

Grid references and scale on an OS map

An English teaching video on this topic from Peekaboo Kidz. Watch it, then scroll down for the lesson.

In a nutshell

Interpret Ordnance Survey maps, including using grid references, scale, topographical and other thematic mapping, and aerial and satellite photographs

What you already know

Part 2 of 19

Before we start

What you already know

You know that grid references go along the corridor, then up the stairs.

Key words

Part 3 of 19

Key words

Words you'll need today

easting: A grid line number read along the bottom of the map.
northing: A grid line number read up the side of the map.
scale: The ratio between distance on the map and distance on the ground, e.g. 1:25,000.

Learning cycle

Part 4 of 19

Learning cycle 1 of 2

Part 1 — Six figures

A short piece of teaching, then a check to make sure it has landed.

Explore the idea

Part 5 of 19

Learn

Four figures first

Each square is named by the easting of its left edge then the northing of its bottom edge. The square with its bottom-left corner at easting 34 and northing 21 is 3421.

Explore the idea

Part 6 of 19

Learn

Six figures: tenths

Imagine the square split into ten across and ten up. A church 6 tenths across and 3 tenths up in square 3421 is at 346213: easting 34 + 6, northing 21 + 3. Still along the corridor, then up the stairs.

Quick check

Part 7 of 19

Quick check

A four-figure reference names a square by its...

Quick check

Part 8 of 19

Quick check

5 tenths across and 8 tenths up in square 4712 is...

Reset break

Part 9 of 19

Pause

That's sitting 1 of 2 done

Stretch, get a drink, look out of the window. There is no timer and nothing is counting down — your place is saved, so you can come back in five minutes or tomorrow.

Stop here for now

Learning cycle

Part 10 of 19

Learning cycle 2 of 2

Part 2 — Distance

A short piece of teaching, then a check to make sure it has landed.

Explore the idea

Part 11 of 19

Learn

Reading scale

On a 1:25,000 map, 1 cm stands for 25,000 cm — that is 250 m. So 4 cm on the map is 1 km. On a 1:50,000 map, 2 cm is 1 km. Each grid square on both is exactly 1 km across.

Explore the idea

Part 12 of 19

Learn

Measuring a winding route

Lay a piece of string along a curved path, mark it, then straighten it against the scale bar. Walkers use this to plan how long a route takes — about 4 km an hour on flat ground.

Quick check

Part 13 of 19

Quick check

On a 1:25,000 map, 4 cm is...

Quick check

Part 14 of 19

Quick check

Each OS grid square is...

Investigate evidence

Part 15 of 19

Evidence 1 of 1

map

An Ordnance Survey 1:25,000 map extract

Ordnance Survey, Present day

Grid square 46 32: a church with tower, a public footpath crossing a stream at a footbridge, contour lines 10 m apart rising to a spot height of 214 m in the north-east corner. Scale bar: 4 cm = 1 km.

OS Landranger and Explorer maps are the standard tools of British outdoor life. Every symbol and grid line is a promise about what is really on the ground.

Think like a historian

Give the four-figure grid reference of the church, then work out the real distance of a footpath that measures 6 cm on this map.

Source: Ordnance Survey Explorer series, published for public use.

View the archive record ↗

Common mix-ups

Part 16 of 19

Common mix-ups

Things people often get wrong

Reading northings before eastings.
Naming a square by its top-right corner.
Forgetting each OS grid square is 1 km.

Challenge round

Part 17 of 19

Game · Sort it

Which of these are true?

Drag each card into the right column. Tap a card first if dragging is fiddly.

True

Not true

Mastery quiz

Part 18 of 19

Marked quiz

End of lesson quiz: Grid references and scale on an OS map

4 questions, marked with the reasoning shown. No timer.

1. Eastings are read...
2. A 6 km walk on flat ground takes about...
3. A four-figure reference names a square by its...
4. 5 tenths across and 8 tenths up in square 4712 is...

Lesson round-up

Part 19 of 19

Lesson round-up

Ready when you are

Quiz score

Not sat

Games

Not played

Points this lesson

Best run

0 in a row

Luna: 0 out of 4 on the practice checks. Only if you feel up to it — one more?

Ask Luna

Do the work

Your written work for this lesson

This is the part you'd do in your book at school. Pick the pieces below, write here or on paper, and photograph anything you draw or work out.

Case study

Flooding on the River Calder

The town of Harbrook sits where a steep valley opens onto a flat floodplain. In December 2015, 120 mm of rain fell in 36 hours onto ground that was already saturated. The river rose 2.4 m in five hours, and 380 homes and 54 businesses flooded. Two roads and the railway closed for eleven days.

Geographers pointed to physical causes — steep slopes, impermeable rock, heavy rainfall — and human causes: moorland drained upstream, new housing built on the floodplain, and drains designed for smaller storms.

Since then the town has planted 40 hectares of woodland upstream, built leaky dams in small streams, and raised flood walls to 1.8 m. In the storm of 2020 the peak river level was 0.3 m lower and 40 homes flooded, not 380.

Written for Good Learning Co.

Reading questions

List two physical and two human causes of the 2015 flood.
Explain how planting woodland upstream lowers the river's peak level.
Using the figures, judge how successful the scheme has been. Quote data in your answer.

Source for this lesson

Use this for the source work task below.

An Ordnance Survey 1:25,000 map extract

map

Ordnance Survey, Present day

Grid square 46 32: a church with tower, a public footpath crossing a stream at a footbridge, contour lines 10 m apart rising to a spot height of 214 m in the north-east corner. Scale bar: 4 cm = 1 km.

OS Landranger and Explorer maps are the standard tools of British outdoor life. Every symbol and grid line is a promise about what is really on the ground.

Source: Ordnance Survey Explorer series, published for public use.

View the original record ↗

Case study notes
Writing
Write the place, the facts and the figures from this lesson so you can revise them later.
Half a page
Explain answer
Writing
Answer in full sentences, giving causes and effects. Use one figure or place name as evidence.
8–10 sentences
Map or sketch
Diagram
Draw the map, cross-section or field sketch with a key, title and labels, then photograph it.
1 map with a key
Data work
Working out
Plot your figures as a graph on paper and write one sentence about the pattern.
1 graph + 1 sentence

Write your answer, notes or working here

Saved as you type.

Photos of paper work, diagrams or working outHow many minutes did the written work take?

Part 1 of 19 · Watch & discover

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