What one contour line means
A single contour line marks a path you could walk while staying at exactly the same height. Step off it uphill or downhill and you cross to the next line. Because every point on the line shares an elevation, the lines never cross one another, and a closed loop of contours encloses either a high point or, less often, a depression.
The contour interval
The contour interval is the fixed height difference between one line and the next, stated in the map legend. A 10-metre interval means each successive line is 10 metres higher or lower. Knowing the interval converts the pattern into real elevation: count the lines you cross, multiply by the interval, and you have the climb or descent.
Index contours are drawn heavier and labelled with their elevation, usually every fifth line. They let you read height quickly without counting every thin line from sea level.
Spacing reads as steepness
The horizontal gap between contours encodes slope. The same height change compressed into a narrow band means the ground rises sharply; spread across a wide band it means a gentle grade.
- Lines close together — steep ground, a cliff edge where they nearly merge.
- Lines far apart — gentle or near-level terrain.
- Even spacing — a uniform slope.
- Spacing that tightens downhill — a slope that steepens, common above valley floors.
Recognising landforms
Hills and summits
Concentric closed loops that grow smaller toward the centre mark rising ground; the innermost ring sits highest. A spot height or a labelled point often marks the top.
Valleys and ridges
Where contours bend into a V or U, the shape points the way uphill in a valley and downhill on a ridge. A valley usually carries a watercourse along its lowest line; reading the blue line with the brown contours confirms which is which.
Saddles and depressions
A saddle shows as two sets of higher contours separated by a low gap — the natural place a path crosses between summits. A closed depression with no outflow is sometimes marked with short tick lines on the inside of the lowest ring.
| Pattern | Landform |
|---|---|
| Small concentric closed loops | Hill or summit |
| V pointing uphill, often with a stream | Valley |
| V or U pointing downhill | Ridge or spur |
| Low gap between two high areas | Saddle or pass |
| Tightly packed lines | Steep slope |
Why it matters on the ground
Reading relief in advance shapes route choices: following a contour to avoid unnecessary climbing, recognising that a short map distance hides a steep ascent, or using a distinct ridge as a handrail in poor visibility. Contours and the compass work together, which is covered in the orienteering article.
General reference on terrain and elevation models in Germany is available through the Federal Agency for Cartography and Geodesy, bkg.bund.de.