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How To Read A Topographic Map Topo Map Tips

How To Read a Topographic Map

In This Guide
  • Topo Map General Concepts
  • Identifying Specific Landforms
  • Picking the Right Map For Your Hike

In the old days of hiking, everyone learned how to read a topographic map because it was the only option to navigate a hike. Today we have handheld GPS units, GPS watches, and smartphones with GPS. Most new hikers can power their phone on, look at a dot on the map, and figure out their position in a second.  And that’s great. Until your device doesn’t work, and that’s where (paper) topographic maps come in. And I know that topographic maps and non-digital navigation can be intimidating, especially for those who never used them. So in this guide, I’m going to focus on the basics of the topographic map so that you can look at one and make sense of it. I’ll dive into the deeper subjects of navigation, map & compass, and overland routes in other guides.

Topographic maps are also known as “topo maps” or “contour maps.”

What Are Topographic Maps?

Topographic maps translate three-dimensional land features into a two-dimensional (flat) map. You can look at a topographic map and quickly see where the hills, rivers, peaks, and valleys are. When you are navigating, a topographic map can show you where you are, what route to take, and which ways are dead ends.

People generally pronounce topographic as TA-PAH-graphic and topo as TOE-PO.

The first country to be mapped entirely with topographic maps was France in 1789, while in the USA, the U.S. Geological Survey (USGS)  just started the process in 1879. The first maps were based on sketches that surveyors made using analog tools to measure distance, angles, and elevations.

Usgs Survey Marker
Look for these survey markers on your hike, especially on summits (there’s a database of all of them in the USA here). They were put there by a human that was surveying to mark an important point for reference. From these markers, surveyors can then calculate other points in the surrounding area.

It wasn’t until the 1930s that aerial photography was incorporated to make the maps more accurate. Today, the USGS doesn’t do human surveys anymore but instead uses satellites and drones to update the topographic maps every three years. And as you probably guessed, today’s maps are all digital but can still be printed out.

Mt Whitney Topoviewer
You can view the latest and greatest USGS topo maps on TopoViewer website. You can see all the map versions of the visible area on the right sidebar. Here you can see the oldest map of Mt Whitney that you can view online dates back to 1907 .
Mt Whitney Google Maps
Topographic maps are not just produced by governments, but also by commercial entities. Google Maps is one that you may have heard of. Their maps usually use elevations from multiple sources, including the USGS and commercial satellite data. While not openly publicized, inside sources hint that Google Maps elevations are heavily dependent LiDAR readings, measured from space with a pulsed laser that can penetrate tree cover.

Are We Talking About Printed or Digital Maps?

Although topographic maps were originally only printed, today they are available as digital maps or printed. When most people say “bring a topo map with you” they are referring to a paper map. But whether the map is digital or printed, the concepts and how to read the map are the same. I’ll talk more about the actual maps that you should use later.

How To Read a Topographic Map

There are a few key concepts you need to know to understand a topographic map. It’s easier than you think.

How To Read a Topographic Map Video

What Are Contour Lines?

Mt Whitney Topo
Contour lines are the key to topographic maps, and are lines that mark a specific elevation (like hillsides and mountains). Everything along a contour line is the same elevation, at least on the map. Theoretically, if you hiked along a contour line, you would never go up or down.
Topo Map Index Lines
Here’s a great example of contour lines. The darker lines, marked with elevations, are called index lines. The number on an index line is the elevation of that line. The elevation is the same along the entire length of the line.
Topographic Map Example 03
The fainter intermediate contour lines between index lines are not labeled, but instead follow the contour interval. Printed maps will tell you the interval on the map key. In this case, it’s 80 feet, so every fainter line is 80 feet higher or lower than the one next to it. Most topographic maps have an index line for every 5th line.
Topo Map Contour Interval
If you have a printed map, look for the contour interval listed on the bottom. If you are looking at a digital map, you can usually click (or right-click) on a point to get the elevation based on the contour lines.
Topo Map On Sat Map
Here’s a flat topographic map laid over a Google Map 3D model. You can see that the lines match the slope of the mountains and canyons.

Want to overlay topographic maps onto a 3D Google Earth model so you can explore yourself? And even put your hike route on there? I’ll show you how at the end of this article.

Topo Map On Sat Map Slopes
The closer the contour lines are together, the steeper the slope. The wider they are apart, the more gradual the slope.

While contour lines may “stack up” on a steep cliff, they otherwise never cross on another.

Topo Map Rock Outcrop
And remember that contour lines are models of the earth. If a slope has a 60 foot cliff like this, it won’t show up on a map with 80-foot contours. Photo Wikimedia
Trails On Topo Map 3d
Here’s a topo map laid on top of a 3D surface in Google Earth. You can see that the trail which crosses no contour lines is flat, while the trail that runs across the contour lines is steep.
Trails On Topo Map Top Down
Here’s a regular, top-down view of the same area from the last image, as you would see it on a topographic map in 2d.

Reading Land Forms From Contour Lines

Let’s start with the basics, a flat area, a steep slope, and a cliff.

Valley In Topographic Map Top Down
In the middle, the contour lines are non-existent, meaning the area is flat. On the right, the contour lines are close to each other, meaning a steep climb. And on the left, the contour lines are stacked on top of each other, meaning a vertical cliff. Note the trail to the left Mile 145, which zig-zags up the slope. A zig-zagging trail is usually switchbacks, and is a clue that the climb is steep.
Valley In Topographic Map
Here’s another view of the last image, this time overlaid onto a 3D surface area.
Topo Grand Canyon 2
And because most people wonder about it, here’s the classic example, the Grand Canyon. Notice how there are many levels of steeply stacked contour lines between the top and the Colorado River below.
Topo Grand Canyon
Here’s what the contour lines look like mapped into Google Earth, looking up from the river to the top. Lots of close contour lines mapping onto cliff walls and steep slopes.

Mountain Peak

Mt Harwood
Here’s the mountain peak of Mt Harwood. Notice how the contour lines get smaller and more circular as they reach the peak. In this case, the peak has also been surveyed and has an elevation, 9552 feet.
Mt Harwood 3d
Here’s Mt Harwood in a 3D view. Also, note that the wider top circle depicts a wider, flatter summit.

Double Summit

Mt Baldy Topo

Mt Baldy Topo 3d

Gully / Ravine / Canyon

San Antonio Canyon
Look for V or U-shaped contour lines to spot a canyon or gully. The more like a V that the contour lines are, the steeper the walls, while a U-shaped formation has less steep sides. These formations usually have a creek or water sources flowing down them as well. The U or V will always point uphill.

San Antonio Canyon 3d

Ridge Trail

Pct On Ridge
At first glance, it looks like any trail in this area will involve climbing. But if you look carefully at the Pacific Crest Trail, you’ll see that it almost follows the contour lines exactly, meaning that it’s (theoretically) pretty flat.

Saddle / Gap / Notch / Pass

Icehouse Saddle
To spot a saddle or pass, look for an hourglass shape on the contour lines.

Icehouse Saddle 3d

Cirque / Bowl

Mt Laconte
The natural amphitheater look of a bowl or cirque can be spotted by looking for steep and circular contour lines.

Mt Laconte 3d

Features on Topographic Maps

Features On Topo Map
Luckily most features on a topographic map are easy to interpret. Here you can see roads, trails, streams, and buildings.

I’m not going to give you an exhaustive list of every feature on a topographic map in this guide, but I will point out some of the more useful features to be aware of on your map. If you want to deep dive into all the features, the USGS has a comprehensive map key here.

A topographic map will not show all the terrain features. Landscapes change and what a mapmaker can fit on a map is limited.

Topo Map Vegetation
Solid green means that the area is mostly covered by TALL vegetation such as a forest. White at the top of contour lines means an alpine zone where the trees have stopped. White in a flat area means a lack of tall vegetation, which could be grass, dirt, desert, etc. Looking at the elevations on a topo map will give the green areas some context.

A white area also doesn’t mean a complete lack of vegetation. There could be grass, meadows, or even overgrown vegetation in a gully.

Topographic Map Water
Blue features are usually water, as you can see by the lakes and streams here. When you see blue contour lines, it indicates a glacier. Standard contour lines are brown.
Trails On Topo Maps
Short black dashed lines are trails. Short black double lines are dirt roads. Do not make the mistake of thinking that the other dashed lines, which are boundaries, are trails.
Big Butt Mountain
Who named all this stuff? The U.S. Board on Geographic Names was set up after the Civil War to standardize names on maps. Anyone can petition them to have a landform named, including the public. You just need some provenance to back up your claim.

Distance on Topographic Maps

I’ll talk about scale shortly, but for most beginners, a key aspect in reading a topographic map is understanding how far apart things are.

Distance Scale On Topo Map
At the bottom of almost every map is the scale measurement. Even digital maps will have a scale (that changes as you zoom) on the bottom.
Measuring Distance With Shoelace
Once you know what the scale is, you’re going to want to measure the trail. The only problem is that trails generally twist and turn, while the scale is straight. A neat trick is to lay a lanyard or shoelace along your route. Then you can straighten it out and lay it against the scale key to find the distance.
Nat Geo Topo Map
Some maps, like these from National Geographic, include the trail distances on each segment, which is very handy.

A mile, or 5280 feet, is derived from the distance that Roman soldiers would walk in 1000 (double) steps. The Latin word for thousand is mille, which the word mile is derived from.

Using Printed Topographic Maps

As I mentioned earlier, there’s a solid amount of hikers who just use a GPS, whether on their phone or on a dedicated GPS unit. If you fall into that category of hiker, I strongly recommend bringing a printed topographic map with you in case your device fails in the backcountry. Even if you don’t know the more advanced skills like orienteering, navigating, or route finding, the paper map is still helpful.

You’ll likely know where you want to hike. And now you know how to read a topographic map. From there you can look at the map, your surroundings, and your expected position, and figure out a course of action if your GPS dies. For the cost of a $12 map, you have an invaluable resource if the electronics fail.

Here’s what I recommend for those who are GPS-dependent or are beginners.

This is a good workflow to start using a paper topographic map. From there you can move onto more advanced skills.

Picking A Map At the Right Scale

To make things simple, think of map scale as how much detail is covered on a map.

Grand Canyon Nps Overview Map
On a “small scale” map like this NPS visitor map, which covers the width of Grand Canyon National Park, at about 300 miles, the level of detail is minimal. In other words, small scale is small (or less) detail.
High Detail Level Map
On a “large scale” map like this topo map, more detail is shown. On a map like this, each inch is about ⅓ mile. “Large scale” equates to a large amount of detail.

The common sizes for printed hiking topo maps are:

Decoding scale is easy. The first number is an inch on a printed map, the second number is the number of inches it represents in real life. So a 1:24,000 map would show 24,000 inches (0.38 miles) for every inch of paper.

Map Recommendations

Good Paper Topo Maps
While you can custom order maps from the USGS, it’s usually easier to buy a third-party map that’s designed to cover a specific area like a park or mountain range, and which are often water-resistant.

Here’s what I would recommend if you’re just getting into carrying a paper map.

Digital Maps

I mentioned earlier that topographic maps were available digitally as well. Digital maps throw a little wrench into the idea of scale. If 1 inch equals 1 mile on a 1:63,360 map, what is 1 inch on a screen? What I can see on 1 inch of a screen on a phone from 2010 is much different then on a high-resolution screen from today. And you can zoom in and out on digital maps too. So how does that all work?

It’s basically a matter of detail that’s included. For example, Garmin sells 24k (roughly equivalent to a quad topographic map) and the 100k TopoActive maps. The 24k maps include more detail than the 100k maps. But for most free digital maps, the level of detail is as detailed as it can be. And most modern map browsers let you tweak the level of detail on a map or do it automatically for you.

Garmin Basecamp Map Detail
In the Garmin Basecamp program you can use the slider at the bottom to control the level of detail that you view on a map.

Digital Map Options

You aren’t limited to the maps that that USGS produces when it comes to digital topographic maps (which you can print). Tools like Gaia GPS (discount code here) and CalTopo allow you to view alternate topo maps and print them. You can even customize the maps to include other layers such as snow cover, weather, etc. It’s very powerful. Let’s look at some of the better digital topographic map options, which you can print out or send to your device.

CalTopo – Mapbuilder Topo

Topo Mapbuilder Topo
The default map in Caltopo is the Mapbuilder Topo, which is based on several sources and updated 4 times a year. This is a solid map that also includes distances between trail segments.

CalTopo – Scanned Topos

Topo Caltopo Scanned
Caltopo also has scanned USGS (in the USA) topographic maps. They may not be the latest, and they often don’t reflect all the trails, but they are your best bet for landform names (like creeks, canyons, etc.).

CalTopo – Forest Service

Topo Caltopo Fstopo
In the old days US Forest Service maps had many more trails than the USGS maps, but today they are almost identical. Many people prefer the cartography choices on the Forest Service maps; it’s less cluttered and busy than the USGS maps. The Forest Service maps don’t have the UTM grid and do have all the Forest Service road numbers labeled, which is helpful.

CalTopo – TF Outdoors

Topo Caltopo Tfoutdoors
The TF Outdoors map is a variation of the Open Street Map that’s focused on the outdoors. These maps generally have lots of trails on them, but the quality of the trails can be variable. Sometimes the trails are small use trails, and other times they can be technical scrambles. For example, in this screenshot from Mt Whitney, the TF Outdoors map shows the Mountaineer’s Route, which is not on the earlier maps and is not really a trail, at least in its tough ending. Some folks might think they can just take a nice hike up the line on the map, which is not the case without more context.

You’ll also notice that this map has a combination of contour lines and shading, which is a computer generated way to illustrate slope, usually found on digital maps.

CalTopo – Global Imagery + Mapbuilder Topo

Topo Sat With Caltopo
Another powerful map is combining the Global Imagery satellite map with the Mapbuilder Topo overlaid at 50% opacity. With this view you can see the natural features with the contours and trails on top.

Gaia GPS (Native Maps)

Gaiagps Native Maps
The (new) native maps in Gaia GPS are probably my favorites. They’re based on multiple sources and the cartography has just the right level of detail and contrast for the outdoors.

National Geographic Digital (Gaia GPS)

Gaiagps Nat Geo Topo Map
This is the digital version of the paper maps. While not as detailed as the Gaia GPS native maps, they’re still easy to read and great for navigating, especially over a larger area. These maps are available with a premium Gaia GPS membership.

AllTrails Native

Altrails Topo Map
AllTrails has proprietary topographic maps which are good. If you’re using the AllTrails app already, generally your best bet is to use the default maps (pictured here).

Exploring Topographic Maps With Google Earth

The best way to really understand a topographic map is to take it with you on a hike, find your position. look at map, look at the features around you, and translate the map features to real-life in real-time. But if you want to practice at home (or when avoiding work), there’s a cool trick that you can do with Google Earth that overlays topo maps onto the Earth’s contours. It’s a great way to prep for a hike and learn topo map features at the same time.

Step 1: Visit CalTopo and Get Your Topo Map

d Topo Map Maker 1
Go to the Caltopo website and find the area that you want to explore. Make sure you have “Scanned Topos” selected as your base layer.
d Topo Map Maker 2
Click on Print and then Download KMZ
d Topo Map Maker 3
Select the area to download with the red bounding box, then click download KMZ.

Step 2: Open the Topo Map in Google Earth

For this step, you’ll need to download and install the free Google Earth program.

d Topo Map Maker 4
Start Google Earth and then load the KMZ file that you downloaded earlier.
d Topo Map Maker 5
Zoom in with the controls on the right. Clicking on the small up arrow will move your perspective closer to the ground so that you’re looking up.
d Topo Map Maker 6
Go all the way down and look all the way up for an “on the ground” perspective.” I’ve included the regular Google satellite photo on the left so you can see how the topo map adheres to the terrain.

You can load multiple KMZ files into Google Earth. Just download multiple areas in CalTopo and open them with Google Earth.

Step 3: Load Your Hike GPX File

If you are examining the area of a hike you’re going to do, you can load your GPX file into Google Earth and it will be overlaid on your KMZ files.

d Topo Map Maker 7
When you open the GPX file with Google Earth, make sure that you have “Create KML Linestrings” checked.
d Topo Map Maker 8
Find your track on the left side and double click on it. The view will adjust to encompass the track. I find it helpful to uncheck the “Points” to keep the view uncluttered.

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