Understanding Contour Lines: A Guide for Hikers

Contour lines are an essential feature on topographic maps that help hikers understand the terrain they will encounter on their adventures. These lines represent the elevation and shape of the land, providing crucial information for planning and navigating hikes. In this article, we’ll explain what contour lines are, how to read them, and how they can help you visualize the landscape.

What Are Contour Lines?

Contour lines are imaginary lines on a map that connect points of equal elevation. They show the height and slope of the terrain above a specific reference point, usually sea level. By examining contour lines, hikers can determine the elevation changes they will face, understand the steepness of slopes, and identify features such as hills, valleys, and ridges.

Contour lines on a USGS map

Key Concepts of Contour Lines

1. Contour Interval:

• The contour interval is the vertical distance between adjacent contour lines. For example, if the contour interval is 5 meters, each line represents a change in elevation of 5 meters. Similarly, if the contour interval is 20 feet, each line represents a change in elevation of 20 feet. Smaller intervals provide more detailed information about the terrain, while larger intervals give a broader overview.

1. Index Contours:

• These are thicker contour lines that appear at regular intervals on a map, usually every fifth line. Index contours are labeled with the elevation they represent, making it easier to understand the height of different areas quickly.

1. Closely Spaced Contours:

• When contour lines are close together, they indicate a steep slope. This means that the elevation changes rapidly over a short distance. Hikers should be cautious in these areas as they might face challenging climbs or descents.

Closely spaced contours indicating steep terrain on Harvey maps

Widely Spaced Contours:

• Contour lines that are far apart indicate a gentle slope. The elevation changes gradually, making these areas easier to hike. Such terrain is often preferred by beginners or those looking for a more leisurely hike.

Widely spaced contour lines indicating flatter terrain on OS maps

Circular Contours:

• Circular contour lines can represent hills or depressions. If the elevation numbers increase towards the center of the circles, it indicates a hill or a peak. Conversely, if the numbers decrease towards the center, it represents a depression or basin.

Circular contour lines indicating a hill/mountain top on IGN france maps

V-shaped Contours:

• When contour lines form a V shape, they typically point upstream in the case of a valley with a river or stream. The V shape’s apex points towards higher ground.

V-Shape contour lines indicating the bottom of a valley on Swiss Topo maps

How Contour Lines Help Hikers

Route Planning:

• By studying contour lines, hikers can plan their routes to avoid overly steep or difficult terrain. This helps in choosing paths that match their fitness levels and experience.

Estimating Difficulty:

• Contour lines allow hikers to estimate the difficulty of their hike. Steeper slopes (closely spaced contours) may require more effort and time to traverse, while gentler slopes (widely spaced contours) are easier and faster to hike.

Identifying Landmarks:

• Contour lines help hikers identify natural landmarks such as ridges, valleys, and summits. This aids in navigation and ensures hikers can stay on track even in unfamiliar terrain.

Safety:

• Understanding the terrain through contour lines helps hikers anticipate challenging sections of their hike, allowing them to prepare adequately and avoid potential hazards.

Identifying Landmarks with Contour Lines

Contour lines are not just about understanding elevation changes; they are also invaluable for identifying natural landmarks in the landscape. Recognizing these features on a map can significantly enhance your navigation skills and ensure you stay on the correct path during your hike. Here, we’ll discuss how to identify some common landmarks using contour lines, supported by imagery to help you visualize these features.

Ridges

A ridge is a long, narrow elevation of land. On a topographic map, ridges are depicted by a series of V-shaped contour lines that point away from the higher ground.

Map Representation:

A ridge line indicated by cascading contour lines on either side of a v-shape. Very similar to valley – only the other way round! EastWest Mapping over Ben Lugmore in the Mweelrea range, County Mayo, Ireland.

In the image above, you can see the V-shapes pointing away from the peak, indicating the presence of a ridge.

Valleys

Valleys are low areas between hills or mountains, often with a river or stream running through them. Contour lines in valleys form U or V shapes, with the closed end of the shape pointing upstream (towards higher elevation).

Map Representation:

V-shape contour lines representing a valley on Kompass maps

The V-shapes in the image point upstream, showing the direction of the valley.

Peaks (Summits)

Peaks are high points on the terrain, often marked by a series of closed, concentric contour lines. The smallest, innermost circle represents the summit.

Map Representation:

Double peaks on Mount Emmett in Tasmania on TASMAP Maps

The tightly packed circles indicate a peak, with the smallest circle at the center marking the highest point.

Saddles

A saddle is a low point between two areas of higher ground, often seen between two peaks. On a map, it appears as an hourglass shape where two sets of contour lines converge.

Map Representation:

Between two peaks. A saddle at the top of Mount Dobson, New Zealand on NZTOPO maps.

The hourglass shape in the image highlights the saddle, a low area between two higher points.

Depressions

Depressions are sunken areas of land. They are indicated by contour lines with hachures or short lines on the inside of the loop pointing towards lower elevations.

Map Representation:

Depressions on a map indicating sunken ground – usually in a circular formation. Typically found on Volcanoes – Teide on IGN Spain maps

The hachured lines in the image point inward, marking a depression.

How These Features Help in Navigation

• Ridges and Valleys: Knowing the location of ridges and valleys can help you choose a path that avoids steep climbs or descents. Ridges are often used as navigation aids because they provide higher ground and better visibility.
• Peaks: Identifying peaks helps in setting waypoints and determining viewpoints along your hike. Peaks can also be useful reference points to ensure you are on the correct trail.
• Saddles: Saddles indicate easy crossing points between two higher areas. They are often the preferred route to traverse from one ridge to another without significant elevation changes.
• Depressions: Recognizing depressions is crucial for avoiding areas that might collect water and become muddy or impassable after rain.

Understanding how to identify natural landmarks using contour lines is a vital skill for hikers wanting to improve their navigation skills. It not only aids in navigation but also enhances your overall hiking experience by helping you better appreciate the landscape around you.

With HiiKER PRO+, you will gain access to all the best mapping in the world under a single subscription. With these maps, you will clearly see how contours affect your route planning and navigation.

Another way HiiKER PRO+ can assist in your navigation journey, is with 3D maps. We display all maps in 3 dimensions so you can have an extra layer of context when looking at what is normally viewed in 2 dimensions. This feature is Exclusive to HiiKER

Purple Lizard maps in 3D over Shenandoah National Park