Advanced guide to reading contours and relief
Understanding contours and relief on a map is essential for safe planning and navigation across the varied terrain you may encounter on your outdoor adventures.
Learn the use and meaning of contour lines on maps and understand how to use them on your map when you're planning routes or out and about.
Hills, slopes and mountains are represented on a map using contour lines. By studying the contour lines you can work out lots about the surrounding terrain including gradients of hills, valleys and steepness of climbs.
The ability to understand the shape of the ground from a map is a useful skill to learn, particularly in mountainous landscapes and when you are out and about hiking. Look for the height and shape of the ground which is shown on 1:25 000 scale maps by brown contour lines. A contour is a line drawn on a map that joins points of equal height above sea level. For 1:25 000 scale maps the interval between contours is usually 5 metres, although in mountainous regions it may be 10 metres.
You can see from the picture above the link between the shape of a hill and the contours representing it on a map. Another way of thinking about contour lines is as a tide mark left by the sea as the tide goes out, leaving a line every 5 metres.
Top tip! Remember contour numbering reads up hill – in other words the top of the number is uphill and the bottom is downhill. Also remember the closer contour lines are together, the steeper the slope.
The steeper the slope the closer together the contour lines will be. You can see this in the examples below:
Now you know how contour lines are created, you can use them to visualise the terrain they show, remembering that:
See also our Advanced guide to reading map contours and relief.
This is part of National Map Reading Week, which encourages everyone to improve their map reading skills and discover new adventures.