How to Read a Topo Map

Topo maps use concentric “contour lines” to show elevation changes, and help people navigate mountains and wilderness areas. The denser the contour lines appear, the steeper the terrain. Topographic maps also tend to show a wealth of natural information, like markings for trails, springs, forests, and swamps, though they tend to include roads as well.

In this post, you’ll learn how to read a topo map, as well as how to use topos to plan outdoor adventures. We touch on a variety of topo maps, including United States Geological Survey (USGS), U.S. Forest Service (USFS), and OpenStreetMap (OSM) topos.

Comparing Topo Maps

Overview Features Coverage & Units

USGS Topos (Classic)

A classic 7.5 minute USGS topographic map for Manitou Springs, Colorado, dated 1961.

The industry standard for topographic information. Possibly still the best topo for hiking.

  • Built areas and man-made features
  • Land cover types
  • Water
  • Labeled trails
  • Natural landmarks

MayContours are toned down compared to newer USTopos, making other features easier to see.

Feet*
Covers the US

USGS Topos (USTopo)

A current USTopo topo map for the Manitou Springs, Colorado area.

“Born digital,” next-generation USGS topo maps published since 2009. Based on seamless digital data, but presented in a familiar quad format. These often have fewer features and less detail than legacy USGS topos. Revised every 3 years.

  • Contours
  • Built areas
  • Roads
  • Water
  • Labeled trails
  • Mountains

Can be missing trails, remote roads, campgrounds, survey markers, and boundaries.

Feet*
Covers the US

FSTopo

An FSTopo topo map for the Manitou Springs area.

USFS-based topos with forest-related enhancements. Often more detailed and up-to-date than USGS topos. Only available for quads containing National Forests or Grasslands.

  • National Forests and Grasslands
  • Forest Service roads
  • Water
  • Natural landmarks
  • Labeled trails and trailheads
Feet*
Covers US National Forests

The National Map

The USTopo topo map for Manitou Springs, via the National Map service.

MayService provides a seamless view of USTopos for use in apps and on the Web.

  • Contours
  • Roads
  • Built areas
  • Water
  • Mountains
  • Labeled trails

May be missing trails, remote roads, campgrounds, survey markers, and boundaries.

Feet*
Covers the US

OpenLandscapeMap

The OpenLandscapeMap viewing area of Manitou Springs.

MayStyles OSM data to accentuate natural features. Good for rural and backcountry areas.

  • Contours
  • Rivers, creeks, and streams
  • Springs and geysers
  • Mountain peaks
  • Unlabeled trails
Meters
Global

OpenCycleMap

The OpenCycleMap topo map for Manitou Springs shows cycling routes through the mountains, as well as bike lanes, bars, and cafes in the city.

Styles OSM data to enhance cycling features.

  • Cycling routes
  • Cycle paths and bike lanes
  • Bike shops
  • Unlabeled foot paths
  • Restrooms
  • Cafes and restaurants
Meters
Global

OpenHikingMap

OpenHikingMap shows trails, restrooms, parking lots, and other hiking amenities.

Styled OSM map for hikers.

  • Labeled foot trails
  • Protected areas
  • Land cover types
  • Peak elevations
  • Restrooms and parking lots
Meters
Global

Gaia Vector Topo

The Manitou Springs area, as it appears on Gaia Vector Topo.

Worldwide topo map based on OSM data, styled like USGS topo maps.

  • Roads
  • Rivers
  • Runways
  • Islands and islets
  • Military areas
  • Natural features like plateaus, peaks, and volcanoes
  • Amenities like toilets, viewpoints, water fountains, and picnic areas
Feet
Global

*Meters in Puerto Rico

What are Topo Maps Used For?

Topo maps provide a bird’s-eye view of a particular area and help you orient yourself in the landscape based on local landmarks. An essential tool for backpacking, hikers use topos to avoid very steep ascents, figure out how to split up multi-day hikes, and determine the right amount of supplies. Topos can also indicate the need to ford a stream, as well as warn you away from dangerous areas like mines, depressions, bogs, and submerged rocks in lakes and streams.

More than just a tool for recreation, topo maps serve conservationists, firefighters, and other professionals who either study the environment or work outdoors. Architects and planners also use them to assess potential build sites.

How to Read Elevation Contour Lines

Contour lines indicate changes in elevation—they act as a 2D tool for visualizing landscapes in 3D. Contour lines show the shape of the terrain, including its hills, slopes, and depressions, by connecting points of equal elevation. If you follow a line, you’ll stay at the same elevation. When you cross a line, elevation either goes up or down.

Think of contour lines as imaginary horizontal planes sliced through the terrain surface. It may be helpful to visualize them as stacked “layers” of the landscape, similar to a layer cake. Lots of contour lines clumped together mean a lot of elevation change, or a steep slope. A large mountain appears as a dense group of lines with a small circle in the center that represents the peak—just picture looking down at a wedding cake from above. Areas with few contours appear relatively flat—more like a 2-tier birthday cake.

Cartographers often use brown hues for contour lines, and they label every fourth or fifth line with the elevation it represents to serve as an “index contour.” They often style index contours thicker or bolder, to make them easier to see. The non-index contour lines give more detail about the landscape, but lack labels usually.

The contour interval, or amount of elevation change between each line, varies from map to map. To figure out the interval, look at the labels for two consecutive index lines and subtract the lower number from the higher number. If the map labels every 5th line, divide by five. For index lines occurring every 4th line, divide the difference of the two numbers by 4.

In addition to contour lines, some modern topos like OpenCycleMap add hill shading, which makes it easier to visualize the terrain in 3D.

Features on Topo Maps

Best known for emphasizing naturally occurring features such as mountains, streams, springs, and land covers, topographic maps also show administrative boundaries, roads, churches, cemeteries, rail lines, and campgrounds.

Topos utilize colors, patterns, and symbols to indicate different features. USGS maps, for example, use light green for parks, light blue for water, brown for contour lines, bright red for major highways, and dashed black or gray lines to represent trails. Typically these features have labels of the same color.

To learn more, check out our post about USGS and other U.S. government topos.

USGS-Manitou-1961-classicClassic 7.5 minute USGS topographic map for Manitou Springs, Colorado, 1961. Credit: U.S. Geological Survey.

OpenStreetMap-Based Topos

OpenStreetMap (OSM) crowdsources detailed maps of the world. Many apps and websites stylize OSM-based data to accentuate specific features specialized for a particular audience.

Drawn in a modern style, OSM-based maps offer a higher resolution that increases zoom potential. OSM-based sources often have more details and more feature types than newer USGS topos, such as improved trail coverage. Note that while USGS typically labels elevations on the 1:24,000 scale maps in feet, OSM-based maps are labeled in meters.

To learn more, read our post on OpenStreetMap-based Topo Maps.

 

Gaia Vector Topo

Gaia GPS develops a worldwide topo vector source based on OSM, styled like the USGS topos. Unlike other tiles-based sources, vector maps get styled and drawn directly to the device. Because the map gets rendered locally, it appears crisper when zooming, and provides better text readability—the smaller download size doesn’t hurt, either.

Now that You Know How to Read a Topo Map

We encourage you experiment with all of these sources in Gaia GPS as you plan your next adventure. Follow the iOS and Android links throughout this email to view our Knowledge Base articles about adding these map sources in the app.

If you have any questions about using topos in Gaia, just email us at support@gaiagps.com.