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1Fix the driver behind crashes, sound loss and screen glitches2Repair Windows errors before they cause bigger problems3Scan for outdated or missing drivers - takes under a minuteTo follow a long-distance walk with an Ordnance Survey (OS) map, choose the right map sheets for the whole trail, learn the map key and grid references, plan recognisable checkpoints, and keep comparing the map with the ground as you walk. A compass can help with direction, but it does not replace route awareness or checking your position.
Choose maps that cover the whole route
OS Explorer maps are the more detailed paper option for walking, at 1:25,000 scale: 4 cm on the map represents 1 km on the ground. They show footpaths, rights of way, open-access land and vegetation. OS Landranger maps use a 1:50,000 scale, where 2 cm represents 1 km; each sheet covers a larger area with less detail, and the range is positioned for longer routes. Compare OS map ranges and coverage.
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Long-distance trails may cross several map sheets. Check the sheet index against the entire route rather than assuming one sheet covers it. The route’s landscape and the level of path and terrain detail you need can help determine whether Explorer or Landranger is the better fit.
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| Map range | Scale | Ground distance represented | Practical trade-off |
|---|---|---|---|
| Explorer | 1:25,000 | 4 cm on the map = 1 km on the ground | More walking detail, including footpaths, rights of way, open-access land and vegetation |
| Landranger | 1:50,000 | 2 cm on the map = 1 km on the ground | Larger area per sheet, with less detail |
Learn the key before setting out
An OS map is a simplified picture of the landscape. Use its key to decode colours, shapes and marks, and find the symbols for the route, paths, access land, roads, streams and buildings. Before walking, identify features you expect to recognise on the ground—such as a path junction, stream crossing or building—so you can compare what you see with what the map shows.
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Read grid references to locate yourself
OS National Grid lines divide the map into kilometre squares. Read a grid reference in two parts: first the easting, moving left to right along the map; then the northing, moving from bottom to top. The mnemonic “along the corridor, then up the stairs” captures the order.
- A four-figure reference identifies a kilometre square.
- Additional digits locate a point more precisely within that square.
Use grid references to mark your start, destination and useful checkpoints. They give you a repeatable way to describe and check a location instead of relying only on a vague estimate of where you are.
Use contours to anticipate the terrain
Contour lines join points of equal height, and labelled contours show height above sea level. Lines close together indicate a steeper slope; lines farther apart indicate a gentler one. Spot heights and symbols for features such as cliffs, scree and streams add useful context about the ground.
Map distance alone can understate the effort involved on sloping terrain. In rough or mountainous country, the straightest line may not be the easiest, quickest or safest. Consider distance, weather, equipment and the walkers’ fitness when planning; following contours may avoid some steep climbs. If conditions or the terrain make the intended line unsuitable, reassess it rather than pressing on simply because it was planned.
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- South West CP
- South West Coast Path (National Trail)
- Cornwall
- Falmouth
- Helston
Plan checkpoints and keep checking progress
Before you leave, divide the route into sections using features you can recognise on both map and ground: junctions, streams, ridges and other clear landmarks. Measure the distance to the next checkpoint using the map scale or a compass ruler. On a 1:25,000 map, 1 mm represents 25 m; on a 1:50,000 map, 1 mm represents 50 m.
As you walk, check whether the expected features appear in the expected order and whether your progress matches the distance you have covered. For travel on a compass bearing, use closer checkpoints—typically 500–1,000 m apart, depending on terrain—because small direction and pacing errors accumulate. Pacing is less reliable on difficult ground, and traversing a slope can pull you off line.
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Take and follow a compass bearing carefully
- Set the direction: place the compass baseplate between your current position and destination, with the direction-of-travel arrow pointing toward the destination.
- Align it to the map: turn the compass housing until its orienting lines line up with the map’s north–south grid lines.
- Account for magnetic variation: use the variation shown in the map legend. It changes over time, so check the current map instead of relying on a correction remembered from elsewhere.
- Walk in short, checked stages: use a visible landmark on the bearing, then confirm your position against nearby map features. Keep the compass away from nearby iron and steel, which can affect its reading.
A bearing is one navigation aid, not a substitute for following the mapped route and checking your surroundings. If the terrain does not match the map or your position is uncertain, stop and relocate before continuing.
Check route-specific conditions separately
General map-reading guidance cannot establish whether a particular trail is currently open, passable, affected by weather or served by transport. Check current official and local information for the route and date you plan to walk; map coverage alone is not confirmation of current access or conditions.
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