How to read Britain’s greatest outdoor tool properly.

There is something deeply reassuring about unfolding a proper paper map on a wooden pub table, tracing a finger along a footpath, and knowing exactly where you are without relying on battery life, signal bars, or an app having a moment.

An Ordnance Survey map is still one of the most useful tools for walking, hiking, trail running, bikepacking, wild exploring, or simply getting gloriously lost in the right direction.

But many people buy one, open it, see a sea of symbols, contour lines, random blue squiggles, and numbers… then quietly shove it back in the glovebox.

That’s a mistake.

Because once you understand how to use an OS map properly, it becomes second nature.

This is your complete guide.

What Is an Ordnance Survey Map?

Ordnance Survey maps are the official mapping standard for Great Britain.

They show:

• Public footpaths

• Bridleways

• Byways

• Roads

• Rivers

• Woodland

• Farms

• Hills

• Churches

• Campsites

• Pubs

• Car parks

• National Trails

• Rights of way

• Boundaries

• Terrain detail

• Buildings

• Land features

In short:

They show the actual world in usable detail.

Unlike many digital maps, OS maps are built for people moving through the landscape, not just driving through it.

The Main Types of OS Maps

Not all OS maps are the same.

Choosing the wrong one is like bringing opera glasses to birdwatching.

1. OS Explorer Maps (The Walker’s Favourite)

Best for:

• Hiking

• Dog walks

• Detailed route planning

• Off-path navigation

• National Trails

• Countryside exploration

Scale:

1:25,000

Meaning:

1cm on the map = 250 metres in real life

Or:

4cm = 1 kilometre

This scale shows:

• Individual field boundaries

• Walls

• Gates

• Streams

• Public footpaths

• Stiles

• Small woodland tracks

• Tiny terrain features

If you're walking in the Cotswolds, Lake District, Snowdonia, Dartmoor, Yorkshire Dales…

This is usually what you want.

2. OS Landranger Maps (Bigger Picture)

Best for:

• Longer route planning

• Cycling

• Driving plus walking

• General countryside orientation

• Larger expeditions

Scale:

1:50,000

Meaning:

1cm = 500 metres

This gives less detail but wider coverage.

You lose:

• Tiny paths

• Smaller features

• Some minor terrain detail

But gain:

• Bigger area per sheet

• Easier macro planning

Excellent for:

Cycle touring, broad hikes, multi-day adventures.

3. OS Road Maps

These are primarily for:

• Driving

• Regional planning

• Journey overview

Not much use for walkers.

4. OS National Trail Maps

Designed specifically for long-distance routes.

Examples:

• Cotswold Way

• Thames Path

• South West Coast Path

• Pennine Way

• Ridgeway

• Hadrian’s Wall Path

These usually simplify navigation around the trail itself.

Good for:

People following a marked route.

Less useful if you want broader exploration flexibility.

Understanding Map Scale Properly

This is where beginners get muddled.

1:25,000

Means:

1 unit on map = 25,000 units in reality.

Example:

1cm = 250m

So a 4km walk would measure roughly:

16cm on the map

1:50,000

1cm = 500m

So that same 4km walk:

8cm on the map

Less detail, more coverage.

Simple.

The Grid System Explained

This is the heart of OS navigation.

Britain is divided into a giant grid.

Every OS map uses this grid system.

Blue lines form squares across the map.

Each square:

1 kilometre x 1 kilometre

This lets you pinpoint exact locations.

Four Figure Grid References

These identify a square.

Example:

SP 3124

How to read:

Step 1: Letters first

The letters identify the large map area.

Example:

SP = a chunk of central England.

Step 2: Numbers

Always:

Along the corridor, up the stairs

Meaning:

Read eastings first (horizontal movement).

Then northings (vertical movement).

Example:

31 = move right
24 = move up

That gets you to the correct square.

Accuracy:

Within 1 kilometre.

Fine for rough location.

Six Figure Grid References

This gives much better precision.

Example:

SP 314246

Split it:

314
246

Interpret:

31.4 east
24.6 north

Meaning:

• Move to square 31/24

• Go 40% across

• Go 60% up

Accuracy:

Within 100 metres.

This is what walkers usually use.

Eight Figure Grid References

Even more precise.

Accuracy:

10 metres.

Used when precision matters.

Less commonly needed for casual walking.

Eastings and Northings

Quick rule:

Vertical grid lines = Eastings
Horizontal grid lines = Northings

Why?

Eastings increase as you go east.
Northings increase as you go north.

Reading Contour Lines

These show height.

Each line joins points of equal elevation.

Close together:

Steep slope

Far apart:

Gentle slope

Concentric circles:

Hill summit

V-shapes pointing uphill:

Valley

Tightly packed chaos:

Prepare your calves.

Rights of Way Symbols

This matters enormously in Britain.

Public Footpath

Usually green dashed line.

Walking only.

Bridleway

Long green dashes.

For:

• Walkers

• Horse riders

• Cyclists

Restricted Byway

Access for non-motor vehicles.

Byway Open to All Traffic

Potentially includes vehicles.

Check local conditions.

Access Land vs Rights of Way

These are NOT the same.

Rights of way:

Legal paths.

Access land:

Areas where open access walking may be permitted.

Common in uplands, moorland, and certain countryside zones.

Don’t assume all land is freely walkable.

Britain is not Scandinavia.

National Trails

National Trails are officially designated long-distance walking routes.

Examples:

• South Downs Way

• Cleveland Way

• Norfolk Coast Path

• Coast to Coast (where applicable depending on publication era)

OS maps mark these clearly.

Often shown with distinct symbols or acorn markers.

These routes usually have signage in the real world too.

Symbols Worth Learning

Some favourites:

🅿 Car park
⛪ Church
🍺 Pub
🏕 Campsite
🚉 Railway station
🌲 Woodland
💧 Spring
⚠ Steep slope
🪨 Crags/cliffs

Learn the legend.

Every map includes one.

Use it.

How to Plan a Walk Properly

Step 1: Pick Start Point

Car park
Village
Pub
Station

Step 2: Check Distance

Measure roughly with:

• String

• Flexible ruler

• Map romer

• Finger approximation

Step 3: Study Terrain

Flat?
Hilly?
Boggy?
River crossings?

Step 4: Check Rights of Way

Make sure your route actually exists legally.

Step 5: Identify Escape Routes

Bad weather happens.

Fatigue happens.

Children revolt.

Dogs refuse.

Know alternatives.

Map Orientation

A map is useless upside down.

Use a compass.

Rotate the map so north matches real north.

Suddenly everything makes sense.

Roads align.
Hills align.
Villages make sense.

Magic.

Compass Basics

You do not need SAS-level navigation.

But know:

• North needle

• Direction of travel arrow

• Bearing scale

At minimum:

Use it to orient your map.

That alone massively improves navigation.

Waterproofing Your Map

Because Britain.

Options:

• Waterproof OS versions

• Map case

• Ziplock bag

• Fold only relevant section outward

Do not unfold entire map in gale force rain.

This is amateur hour.

Common Beginner Mistakes

Trusting the phone completely

Battery dies.

Signal vanishes.

Rain kills touchscreen usability.

Carry paper backup.

Misreading scale

A route that looks tiny can be brutal.

Ignoring contour lines

“This looks like a pleasant shortcut.”

No.

That is a vertical punishment wall.

Forgetting access rights

Not every visible track is public.

Getting grid references backwards

Remember:

Along the corridor, up the stairs.

Always.

Should You Use Paper or Digital?

Best answer:

Both.

Digital:

Fast planning
GPS reassurance
Route recording

Paper:

Reliability
Big picture awareness
Battery independence
Better terrain understanding

An OS map is not old-fashioned.

It is a genuinely superior navigation tool when properly understood.

Apps are convenient.

Maps teach awareness.

And there is something far more satisfying about finding your way across moorland, woodland, ridge, or hidden valley with nothing more than a folded sheet of paper, a compass, and a bit of competence.

That still feels like adventure.