It may also be called a col or a bealach. Here the ground descends on three sides (ahead and to each side of us) and goes up on one side (back toward the summit).Īs we reach the gap between the two hills there is a small flat area (point B at 103 metres) and this is known as a saddle. If we were to walk down the right-hand slope of the larger hill in the diagram we would be walking down a feature called a spur, which is denoted on the map as ‘v’ shaped or chevron contour patterns.

When we are stood on a summit of a hill the ground drops away from us in all directions and this gives us the distinct ring shapes as seen in the diagram below. For example, if we look at the tops of the mountains we can see the contour lines forming circle like shapes, or rings, these are indeed called ring contours and denote a summit. If we look closely at the contour lines on a map, we can see other patterns emerging.

We can use this information to determine which ground is safe to travel over and which slopes may be too steep to negotiate safely. On shear vertical cliffs the contours would effectively be stacked one above the other and form a single bold line. We can see this on the NE slopes of Binn an Choire on the image below. As the horizontal distance decreases and the contours get closer together so the ground steepens, to the point where they almost blend together in one thick black line. If the horizonal distance between each contour is large, as in the valley on the left, then the ground is very shallow.

We know that the vertical interval (the distance between) the contours is constant, in the image below this is 10 metres. This is the beginning of contour interpretation, which really means understanding the patterns that contour lines make on the map. When looking at the contours on a map many of you will intuitively know that when the contour lines are close together the ground is steep and when they are well spaced the ground is flatter. The numbered contour lines are often depicted as thicker or bolder lines and these are called index contours. The numbers also allow us to determine which direction is uphill and which down. In the image above the map on the left has 10 metre contour intervals and the one on the right has 15 metres contour intervals. On most maps they are drawn at 10 metre vertical intervals, but they might be 5, 10, 15 or even 20 metre intervals, depending on the scale of the map and the level of detail provided (see below).Īt regular points on the map the contours are numbered, this gives us the height above mean sea level of a particular contour line and helps us to determine the contour interval, the vertical distance between each contour line. To give shape and meaning to the contour lines they are drawn every few metres apart. It is this line that the cartographers put on the map. It would snake around the hill, in and out of the small valleys and around knolls, always staying at 200m above sea level, creating an imaginary line on the landscape. The most useful of these is using contour lines.Ī contour line joins points of equal height, if you walked around a hill side at exactly 200 metres above sea level and placed a flag every few metres the line joining these flags together would be the 200 metre contour line. To be able to depict three dimensions on the flat surface of a map the cartographers employ a number of techniques. What are Contours?Ī map is a 2-dimensional representation of the 3-dimensional world. An experienced and competent navigator will look at the contours early in the process and use the information they provide to make good navigation decisions. However, all too often contour interpretation is overlooked in favour of more obvious features such as streams and forests. Understanding contours and being able to interpret the shapes they make on a map is a very powerful navigational tool.

Easy contour landscape