We are all familiar with many different types of maps, each of them with a different purpose. The compass and the map should come handy when you are traveling or going on an adventure. But do you know how to read a topographic map? Learning how to read a topo map (as many like to call it) is also essential as it can tell you in detail the terrain you are going to explore.
Read on to learn about some basic concepts like how the contour lines can help in visualizing the terrain, how the map scales work, and other details on the map that you need to know.
Steps In Reading A Topographic Map
- Step 1. Understanding the contour lines
- Step 2. Know the features of the map
- Step 3. Learn what each color represents
- Step 4. Know the scale of the map
- Step 5. Find the North
Understanding Contour Lines
You can use the simple trail maps when you are planning your trip but not when you are navigating the field. What you need is a topographic map to navigate because it gives you the power to visualize the terrain in 3D from a piece of paper. The thing that makes this possible are contour lines. Here are the roles of contour lines on the map.
- It indicates how steep the terrain is. Contour lines connect the points that have the same elevation. When the elevations are close together, you can see the contour lines changing rapidly in a short distance, and the terrain gets steep. If the contour lines are far apart, this means that the elevation is slowly evolving, meaning the slope is gentle.
- It indicates the shape of the terrain. When you see uneven concentric circles, it is showing you a peak, and the areas between these peaks are passes. To study the topographic map, you need to pick a familiar area where you can match the features of the terrain with the contour lines on your map.
Index Contour Lines – when you look at the contour lines, you will notice that the fifth contour line is thicker than the rest, and you will find the exact elevation somewhere in these lines.
Contour Interval – you will also notice that the change in the elevation from one contour line to the next does not change in the same map. Many topo maps have a 40 or 80 contour interval. What does that mean? The 80-foot interval implies that each of the contour lines is 80 feet (vertical) away from the next. You can find this on the legend section of the map.
Circle with Tick Marks – the circle on your map with tick marks denotes a depression and not a peak. You will also see that the elevations are decreasing when you get near the depression.
What Are Map Scales?
If you want to know how detailed your map is, you should check the map scales. For example, when you have a 1:24000 scale, that means that in reality, an inch is equivalent to 24,000 inches.
You can also look at the map for a representative scale to help you picture the actual distances. Using a string or the edge of a compass, you can get a rough estimation of your hiking distances with your map.
The Map Legend
The map legend is an essential part of your map that is loaded with navigational data and clues. You need to study each symbol, lines, and colors and know what each means. For example, the green color indicates denser vegetation, and a lighter colored area is open terrain.
The legend contains valuable data too like the map’s scales, the contour-and-index line intervals, the grid system and the magnetic declination (needed when setting up your compass).
To familiarize yourself with map reading, you need to get a familiar area as a sample. Envisage how the contour lines on your map can relate to the real landmarks in the area. Get features like saddles and peaks and check the subtler features like the cliffs (notice how the contour lines are grouped) and the ridgeline that connects the peaks (the contour lines are decreasing from the elevation on each side).
You can practice your map-reading skills with every trip. You can mentally note the landmarks as you go on. If you have become an expert map reader, you will rarely get lost.
Other Features Of A Topographic Map
Aside from the contour lines, you will also find additional features on the topographic map, which may include the following:
- Cultural – like power lines, railroads, boundaries, urban spaces, and buildings.
- Natural – consists of vineyards, parks, orchards, and woods.
- Aquatic – like streams, rivers, seas, lakes, waterfalls, and swamps.
- Relief – are the canyons, depressions, slopes, valleys, mountains, and plateaus.
- Toponymical – these are the names of the highways, water features, and places.
FINDING TRUE NORTH
For you to use your topographic map along with the compass when you are on the trail, you should be able to identify where north is. This task is straightforward as the north is always at the top of your map.
WHERE TO GET A TOPOGRAPHIC MAP
Years before, the U.S. Geological Survey (USGS) was the gold standard for topographic maps. Their maps cover the entire country, and the rectangular areas of the land are known as quadrangles. Nowadays, the maps are available from online resources. This allows the maps to be continuously updated. The maps that we can download have a few drawbacks, not all of them have the complete trail information, and some lack in-field verification.
Maps Available from Specialty Companies
Several companies produce many topographic maps. These maps’ highlights have critical features highlighted and are updated regularly. However, these maps may only have popular areas.
Another source of topographic maps can be the growing number of websites where you can customize and download the map of the area on target. Some of these maps are free with other subscriptions.
Many public areas like the national forests, national park, recreational areas, and state parks have maps available to cover their areas. You can also check their websites for downloadable maps.