How to Read a Topographic MapPublished on 11/24/2021 · 8 min readCamping & Hiking Expert Elle Matthews walks you through how to read a topographic map so you can understand the terrain, elevation, and more.
Wanderlust is talked up like you should get lost in the woods and find yourself. I do think there is something cathartic there, but it’s still important to plan and prepare. You can’t plan for everything, but you can prepare yourself to know how to respond to many things!
Let me introduce you to your good buddy the topographic map, or topo for short. Topo maps take a three-dimensional landscape, flatten it onto a piece of paper, and set it to scale. They provide intense detail of natural landscapes and man-made features. This resource has been used for a variety of reasons starting all the way back in 1879.
If you're looking at your first topographic map right now, you might be thinking that it will be more useful as fire kindling. So, let’s get into what the heck we’re looking at and how it’s used in the hiking community.
Let’s start at the bottom and figure out all this stuff first.
Rule number one in choosing a map is making sure you have the most up-to-date version available. There are various production dates listed in the left corner of the map, but what you want to reference is the date found on the bottom right-hand side.
Next to the date, you’ll find your map’s pinpointed location and a grid of surrounding quadrangles. A quadrangle, or a quad for short, means that north and south are curved to the Earth’s latitude lines. The names of the quads are derived from the city, town, or well-known features there.
Scale size determines the amount of detail you see on your map and it helps with measuring distance.
The fractional scale is a ratio measured in inches of map distance to distance in the real world. 1:24,000 is a size commonly used and is also referred to as a 7.5 minute quadrangle map — this means 7.5 minutes of longitude and latitude, or eight miles north/south and six miles east/west. Don’t be overwhelmed by that information, all I did was say the same thing in different ways like I’m about to do again…
One inch on the map = 24,000 inches or 2,000 feet of ground distance.
The bar scale provides a reference of distance in different units including kilometers, meters, miles, and feet.
Scale goes according to straight lines, so when measuring distance through switchbacks and other turns along your route, use your shoelace against the bar scale and you’ll cruise right along!
Your map shows you the path to follow according to the true north, but your compass needle points toward the magnetic north. Declination is the difference between true north and magnetic north.
Magnetic north floats around with the Earth’s magnetic poles, it is always moving and at an unpredictable rate. True north is a fixed point that always leads to the geographic North Pole; it’s the place where all lines of longitude meet. Some maps show grid north, which is the angle of difference when you take the rounded lines of longitude and straighten them out in order to create a grid.
On the diagram above, you’ll find MN is your magnetic north, GN is your grid north, and true north (TN) is marked with a star. Use the angle of difference between TN and MN in order to adjust your compass’ north. It might feel a little strange having your needle outside of the marked north on your compass, but imagine how far off track you’d go if you didn’t make that adjustment. Positive declinations point east and will be positive numbers, and negative declinations point west and will be a negative number.
The magnetic poles have been recorded to flip every 200,000 years or so. It has now been around 700,000 years, so you may have a chance to witness a moment in time when north becomes south and south becomes north! They’re acting more shifty than usual these days.
Universal Transverse Mercator (UTM) is a type of plane grid system. The lines are similar to longitude and latitude but are laid straight and then organized into zones. UTM coordinates are noted in full length on the corners of your map as eastings and northings. Along the edges of your map are shortened marks of every 1,000 meters. This example shows 43,59,000 northings and 4,03,000 eastings followed by 60 and 02 (43,60,000N and 4,02,000E).
Outside of the UTM coordinates are the familiar longitude and latitude coordinates. In this example, you can see 39 degrees N and -106 degrees W.
UTM coordinates take on various formats. Map tools is a neat source for practicing navigational skills like identifying UTM coordinates and longitude and latitude.
Townships and Range
The red lines that run across your map represent the U.S. Public Lands Survey System. The township lines run east to west, parallel to a base line, and the range lines run parallel to a principal meridian that goes north to south. The division of townships are numbered 1 to 36. This system is set in place to identify and locate areas of land. With each zone measuring one square mile, you can use these as a tool to identify nearby land features.
Map Legend and Symbols
There are pages of symbols and explanations of what they mean that you can reference here. This is why there are different scale sets; if all of this information was on a small scale map, it would be a little too much to handle.
Black: Roads, railroads, bridges, trails boundaries, and names.
Blue: Water; glaciers, rivers, and creeks.
Green: Land with trees or other types of vegetation.
White: An area with little vegetation, like sand or gravel.
Red: Major highways.
Brown: Contour lines.
All the squiggly lines that cover your map are called contour lines. These are the lines that add depth and breathe life into your map. They show shape and change in elevation. Strain your eyes a bit and explore details of the world with me!
When you trace your finger along one contour line, you are staying at the same elevation the whole way around. When you jump up or down one line, no matter how close or far away it looks, in reality, it is a consistent vertical distance. That measured distance is known as the Contour Interval. Typically it is 40 or 80 feet; you’ll find it printed at the bottom of your map below the bar scale.
Every fifth contour line is bolder than the rest. These lines are referred to as index lines. Written somewhere along these lines, you’ll find the elevation.
Common Terrain Features
Peak/Summit: The highest point of a mountain. It will look like a small circle that’s marked with its elevation or an X.
Ridge: A long, continuous stretch of elevated land. Contour lines on a ridge are in the shape of a V or U and point down.
Spur: Elevated land with three low points that has a more gradual change in elevation than a ridge. It commonly juts off a mountain or ridge and its contour lines are in the shape of a U or V.
Hill: A raised area of land, less steep than a mountain, with a summit. Contour lines will be more gradual and far apart with a circle at the center indicating the top.
Cliff: A steep drop in elevation. Contour lines will be stacked on top of each other and appear to be intersecting. This is sometimes unseen if the drop is sharper than the contour interval.
Plateau: Elevated flat land on at least one side.
Fun fact! The Colorado Plateau lies over a portion of Colorado, Arizona, Utah, and New Mexico. There are nine national parks and 18 national monuments located within its boundaries!
Valley: A stretch of depression between mountains and hills that usually directs toward water. Contour lines will be pointing in an upward direction toward the top of the mountain.
- Gulch: a V-shaped valley.
- Ravine: a small valley.
- Canyon: a gorge; a deep ravine.
Saddle: All the same name for a lower point between two elevations. The contour lines typically make a figure-8 shape.
- A saddle connects two mountains.
- A col connects two peaks.
- Gaps are more rugged and difficult to get through passes.
Where to Find Topographic Maps
Pull from one of these sources and practice!
United States Geological Survey is an organization that published its first topographic map in 1882; this is the hub for everything maps. Free downloadable maps are available through topoView and are updated every three years.
Free downloadable and printable maps are offered through NatGeo. They pull from USGS’s collection, so just make sure to check the dates, as they are not all current. You have the option to order current Trails Illustrated maps — they are durable and waterproof, so I highly recommend carrying one with you on the trail.
CalTopo is a user-friendly resource that offers a huge variety of layers to help you visualize the land. It is very helpful to look at while learning how to read a topo map.
If you’ve got that itch to wander where the wifi is weak, then carry on with common sense, your compass, and your map. If you have any questions or want to get geared up for your next big adventure, reach out to a Camping & Hiking Expert here on Curated. You’ve got what it takes to be an explorer of the world!