How To Read A Topographic Map
Last Updated on September 2, 2020
A topographic map is a two-dimensional figure used to represent the details of the area you want to know. The map consists of roads, rivers, lakes, mountains, trails, and other geographical properties of any area.
It is a necessary item to bring with you when you have less idea about a place. But reading the map and understanding it is equally important. Here are a few points described to read a topographic map properly.
Scaling
It is crucial to determine the distance from your current location to the desired location. Scaling of a topo map helps to visualize the relative lengths of different places. A scale like 1:x (where x is any number) reveals that 1 inch of the map is equivalent to x inches in practical life. The map with a large scale covers a broad area but contains less information about it. But map having a small scale shows more details of a limited area.
Contour Lines
Contour lines are used to display the shape of the surface of any area. These lines never overlap each other. Closer lines dictate that the level of elevation varies a lot within a specific distance. In this case, the plane is steep.
On the other hand, extended lines indicate that the elevation levels don’t change much within a particular area. So the terrain has less inclination. The nature of the terrain is almost the same in every point of a contour line. The value of the overall elevation level is written at any point in every fifth line. This line is known as the index line. It is always thicker than the other lines.
Contour Interval
The variation of the elevation level of two consecutive lines is always uniform. The Contour interval is the measurement of the vertical distance of two contour lines. They depend on the scale of a map as well as the nature of the terrain. A large contour interval indicates a wide area and a small one points out a narrow area. It also helps to calculate the elevation of any point between two lines.
Depression Contour
It is a place where the elevation of the outer area is larger than the inner area. In short, they represent a hole or cave instead of a peak. If a contour line has a ticked mark inside of it, it is showing depression.
Landscape
This map also allows visualizing a three-dimensional landscape on a piece of paper. A normal map may represent only a few details, where a topographic map delivers more accurate information and more details.
- Thick green lines describe a wide area of vegetation or a forest.
- Blue marks water sources like rivers, lakes, streams, ponds.
- The less colorful portion represents an open terrain.
- Bown color means the contour lines.
- Black indicates roads, railways, and other objects.
- Red symbolizes highways and boundaries.
Identifying Features
The series of contour lines symbolize a mountain. A sequence of V-shaped contour lines detects a valley. On the other hand, the series of U-shaped contour lines represents a ridge. If the place is close to the sea and the contour lines are close to each other, it indicates a cliff. The centered circle of a group of the contour lines represents the peak of a hill.
Calculating Directions and Positions
You always need to have a clear idea about the latitude and longitude of the map. Vertical and horizontal lines define longitude and latitude, respectively. One of the lines of latitude identifies the middle of the earth. It is called the equator. They use the degree as their indicator. One degree is almost equal to 70 miles. So with the help of them, you can easily measure the distance between any two points.
Magnetic Declination
Always remember that the North lies in the upper portion of the map. But the magnetic North is not the same as the actual North. So for better navigation, always use a compass. Magnetic Declination exists in the lower part of the map. It shows the difference of angle between the geographical North and the magnetical North. Place the compass pointing to the magnetical North, and it will show you the total covered area by the map.
Practicing the Visualization
Whenever you are going for a trip or a ride, bring a map with you. Then compare the information provided in the map with the real measurement. Try to find out similarities between the contour lines and the actual terrain.
Also figure out the similarities between the details of roads, buildings, lakes, forests, and other information with reality. Calculate the exact distance and the distance showing on the map. By doing so, you can understand the map in a convenient way. As time grows, the surface of earth changes, so always use the latest map.
Final Words
Nothing can be more useful than a topographic map for knowing about the area you are about to explore. The informative piece of paper helps to show all the characteristics related to a surface. So, never forget to carry it along with you, when you opt for an unknown or less known place.
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