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How to navigate || Part 2: Maps & resources

by Assessor
How to navigate || Part 2: Maps & resources

For my earliest hikes, I utilized whatever resources were conveniently available and that seemed sufficient. Before thru-hiking the Appalachian Trail in 2002, for example, I purchased the ATC Data Book and downloaded the ALDHA Thru-Hikers Companion. And to explore Colorado’s Front Range the following summer, I bought a few National Geographic Trails Illustrated maps that covered the area.

But when I started adventuring off script — starting with the Sierra High Route, culminating with the Alaska-Yukon Expedition, and continuing with high routes of my own — I had to create some or all of these materials from scratch. Through this process, I developed what I believe to be an optimal system of maps and resources, which is the subject of this post.

This article was originally published four years ago, but I’ve updated it and grouped it with a multi-part series about the Navigator’s Toolkit, which will help readers with learning how to navigate. Read the full series:

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My three standard map types: custom detailed maps on 11 x 17 paper, a commercial overview map, and digital maps and layers on a smartphone.

Topographic maps

I normally pack three types of topographic maps:

  1. A paper small-scale overview map,
  2. Paper large-scale detailed maps, and
  3. Digital maps (and sometimes additional imagery or data) on a smartphone.

Paper vs digital

The current generation of thru-hikers might consider me “old school” for my continued reliance on paper maps. But overall I think that they are functionally superior. They:

  • Offer a significantly larger viewing window: an 11 x 17 sheet has 187 square inches of topographic detail, or about 13 times more area than the screen on my Pixel 2 XL.
  • Can be written on, to make route notes and draw bearings;
  • Withstand impact, like when dropped or sat on;
  • Remain functional after being exposed to water, so long as a laser printer was used;
  • Do not require batteries or recharging;
  • Are more easily viewed by multiple people, like when discussing route choices.

I understand the appeal of digital maps, however. They don’t require a good printer or a trip to REI. A phone or handheld GPS is more pocket-table and less unwieldy. The mapping software can reliably pinpoint your location, and quickly calculate distance and vertical; and for a long trip, it’s also more cost-effective.

Printing tips

Elsewhere I have detailed my process and recommendations for exporting and printing custom maps. Read that now.

1. Paper overview maps

Overview maps normally have a scale of 1:50,000 to 1:100,000, meaning that one unit on the map (e.g. inch, centimeter, thumbnail) equals 50,000 or 100,000 units in the field. While planning a trip, I use these small-scale maps to:

  • Develop a general understanding of the landscape, including the main watersheds, the road system, and trail network;
  • Identify a general route, and potential alternates; and,
  • Work through logistics, like travel, permits, and resupply.
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Several examples of overview maps. Commercial recreation maps are best since they are updated regularly and include more than just topographic data. When unavailable, I custom print USGS 30- x 60-minute or 250k map series on 11×17 paper (upper right).

In the field, overview maps are useful for pinpointing distant landmarks, mid-trip planning discussions, self-evacuations, and detours.

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From Colby Pass in Sequoia-Kings Canyon, we were intrigued by a prominent peak on the north horizon. Using our Trails Illustrated overview map, we concluded that it was Mount Goddard, 30 miles away and still inside the park!

On its own, an overview map can be adequate for on-trail navigating. However, I’d caution against this: it’s a missed learning opportunity.


By definition, the topographic detail on a small-scale map is compressed, making it difficult to associate features on the map with features in the field, particularly subtle ones. If your map-reading skills are only so-so, trying to improve them using small-scale maps will generate limited results.

Making matters worse, popular overview maps do not use a standard scale or contour interval, so your brain must relearn this relationship with every new map. For example, the overview map I used in July of Yosemite National Park is printed at 1:80,000 and has 50-foot contour lines. Whereas the map I will use next month in Rocky Mountain National Park is printed at 1:50,000 with 50-foot contour lines, making the topography appear 37 percent less steep.

Also, these popular maps almost always have shaded relief. The shading causes features to stand out more, but plays tricks with your eyes when not viewed from the south side of the map and looking north.

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A closeup reveals how much topographic detail is compressed onto these maps. The upper map of Utah is at a scale of 1:75,000, or more than 1 mile per inch; the lower map is 1:250,000, or 4 miles per inch. These maps are most useful when planning a trip, and may be sufficient in the field only for on-trail itineraries.
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When a shaded relief map is viewed upside down, the shading can fool your eyes, making canyons look like ridgetops and mountains look like valleys. For field use, it’s better to use a map without shaded relif.

For an overview map, I prefer to use a commercial recreation map, such as from National Geographic Trails Illustrated, Tom Harrison, Green Trail Maps, or Beartooth Publishing, because they:

  • Are revised and updated regularly;
  • Conveniently include things like parking areas, backcountry campsite locations or zones, and services like permit office and visitors centers; and,
  • Encompass a specific area, like a National Park or Wilderness Area, where my entire trip will probably take place.

Individual recreation maps cost $10 to $15 and are available online and from local retailers. If you are Premium member of GaiaGPS ($30 per year), you can access the Trails Illustrated maps digitally (via the website or app); from the website, they can also be printed.

When recreation maps are not available, the next best option is to create your own. In CalTopo, another recommended platform, use the MapBuilder Topo layer. In GaiaGPS, the best layer is probably Gaia Topo, but it’s also worth looking at Mapbox Outdoors or Outdoors by Thunderforest,

A final option is purchase USGS 30- x 60-minute maps, which are at a scale of 1:100,000. Unfortunately, these maps are not updated regularly (many are 25+ years old) and they omit useful recreational details.

2. Paper detailed maps

At home, I rely on detailed maps to more precisely plan my route. In the field, I rely on them to navigate and to find campsites and water sources.

In the US, the gold standard for large-scale maps is the US Topo series, produced by the United States Geological Survey (USGS). US Topo is modeled after the pre-digital 7.5-minute quadrangles.

Each paper “quad” — of which there were about 55,000 — represented 7.5 minutes of latitude and 7.5 minutes of longitude. (In this instance, “minutes” are not in reference to time. The earth is divided into 360 degrees of longitude and 360 degrees of latitude. Within each degree, there are 60 minutes of lat and long, and within each minute there are 60 seconds.) This equated to about 8.5 miles of latitude (map height) and about 5.5 to 7.5 miles of longitude (map width), since the physical distance between lines of longitude decreases towards the poles.

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Left: An original USGS 7.5-minute quadrangle. Right: A custom map based on the same map series, digitally annotated and exported to a print-ready 11×17 PDF using CalTopo.

The 7.5-minute quads and US Topo have a scale of 1:24,000. One inch on these maps equals 0.3788 miles, since there are 63,360 inches in one mile.

The most common contour interval is 40 feet. But the USGS was not always consistent in its units or contour intervals. For example, some parts of the High Sierra have 20-meter contours, while 80-foot contours were used in the Tetons and Glacier National Park.

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The natural scale of 7.5-min quads is 1:24,000, so topographic detail is much clearer. This series is the gold standard for topographic maps in the US, and ideal for precise navigating.

Today, scans of the 7.5-minute maps can be accessed digitally, like through CalTopo (my pick) and GaiaGPS. A related product that is better for Forest Service lands, FS Topo, is also available through these platforms. The 7.5-minute scans and FS Topo layers can be exported out of CalTopo and Gaia into print-ready PDF’s.

An 11 x 17 tabloid print-out does not rival the beauty or quality of an original quad, however. To be nostalgic, purchase them directly from the USGS, or look for a wooden bureau with coin slot-style drawers at your local outdoor retailer.

Special circumstance: Alaska

The maps generally available for Alaska are different than those in the lower 48.

Recreation maps are increasingly available for Alaska, particularly the National Parks. For areas where they are not available, make your own in CalTopo or Gaia, or track down the beautiful 1- x 2-minute series that are printed at a 1:250,000 scale with 250-foot contours.

The US Topo layer is increasingly available for Alaska, but I still prefer to use scans of the older 15-minute quads, which are printed at a scale of 1:63,360 and normally have 100-foot contour lines. A lot of topography hides in these maps, but the Alaskan landscape is so huge that the scale and contour interval is more becoming of it. The incredible detail of the standard 1:24k/40-foot series undermines its usefulness.

Read the comment from Roman Dial for additional perspective on maps in Alaska.

3. Digital maps

As a backup and a supplement to my paper maps, I also load digital maps onto a smartphone (my pick) or GPS unit, and sometimes other layers, too, like Landsat imagery and properly boundaries.

If I lose my paper maps or if I get way off route, digital maps become invaluable. Both instances happen. I’ve found other people’s maps, and I’ve had clients lose their maps. And on one of my first guided trips, we bailed out of the Alaska Range and ended up 100 miles away from our intended exit point, way off both our overview and detailed maps.

Digital maps have inherent value, not even accounting for the powerful software that accompanies them and that I will discuss more in Part 3 of this series.

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A screenshot of the 7.5-minute layer, as seen in the GaiaGPS app


In addition topographic maps, I also like to have two other items.

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Route description

A route description is useful for providing general information about a route (or a section of it), interesting historical and scientific knowledge, personal anecdotes from the author, and in-depth explanations of tricky sections. I tend to get annoyed by wordy descriptions containing information that is obviously and more efficiently conveyed by a topographic map.

While preparing for routes for which no route description was publicly available, I have made my own. In these DIY guidebooks, I consolidate bits of information from email and phone conversations, online forums and trip reports, land manager websites, and my travel reservations. I have learned to copy the content verbatim, because it’s full meaning often can only be interpreted once in the field.


A datasheet is a list of key landmarks (e.g., intersections, passes, creek crossings, shelters), usually at least with the incremental and cumulative distance between them. In my high route guides, I also include vertical change because it’s more revealing than horizontal distance.

A datasheet it not useful for a spontaneous itinerary, because you’ll be off it after an intersection or two. But it’s extremely convenient for established trails and routes, like a long-distance trail. With a datasheet I can quickly:

  • Dead-reckon to future landmarks;
  • Identify realistic camping areas for the night or future nights; and,
  • Determine if I’m ahead or behind pace.

The information on a datasheet can be calculated manually, at home or in the field, for between two points or between many points. But digital measuring tools in CalTopo and GaiaGPS will yield more accurate data and make much quicker calculations.

Datasheets can be reconfigured into other quick-reference lists, such as of:

  • Water sources in an arid area;
  • Resupply points on a thru-hike;
  • Designated campsites.
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An example datasheet (left) and route description (right)


To keep my maps and resources clean, crisp, and dry, I keep them in a gallon-sized freezer bag. I carry two bags:

One bag is for materials that I’m using right now or will be using soon, like before the end of the day, and possibly before a long break when I would have the chance to resort things. I keep this bag free of clutter — the more that’s in it, the less accessible things are — and I store it in a secure but easily accessible location, like a dedicated side pocket on my backpack.

The other bag is for materials that are not presently in use, as well as other paperwork like my backcountry permit and sometimes some writing paper. I try to compartmentalize maps and resources that I have already used, so that I don’t waste time looking through them for my “next” map. I store this bag inside my pack, usually sandwiched between the pack liner and the pack body fabric.

Gallon-sized freezer bags are tough and inexpensive, and they fit perfectly my 11 x 17 maps after their half-inch margins have been removed and they’ve been folded in half. For trips longer than about 5 days, I will take a third bag so that I have a fresh and clear bag for the second half of the trip.

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Leave a comment!

  • What types of maps do you carry?
  • Do you prefer paper or digital maps?
  • How does the length and difficulty of your trip affect your choices?

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