When I mostly only followed established backpacking trails or routes, I relied heavily on existing resources — topographic map sets, route descriptions, databooks, and now digital trail apps — under the assumption that they were sufficient, which they normally were. But when my trips became more of the choose-your-own-adventure variety, I had to develop these resources from scratch, which forced me to think harder about them and which gave me the opportunity to experiment with different systems and methods.
In this post I want to focus specifically on topographic maps, since they are the single most important navigational resource. That is to say, it’d be difficult — if not impossible — to hike a unique route without topographic maps, while doing it without a route description, databook, or digital app is quite plausible.
I normally carry three types of topographic maps:
- Paper overview maps
- Paper detailed maps
- Digital maps on a GPS unit
On most trips, I use exclusively the printed maps. My GPS unit and the digital maps stored in its memory are purely for backup. There are many reasons I prefer paper maps over digital ones:
- Huge viewing window: 187 square inches of topographic detail on an 11×17 sheet, versus 10 square inches on a 5-inch digital screen;
- Writeable surface, so that I can make notes about the route;
- Will not break if dropped or smashed;
- If exposed to water, laser prints are fully recoverable by drying them out; and,
- Do not require batteries or recharging.
The considerations of cost and weight are trip-dependent. For example, a handheld GPS unit is an expensive purchase for an occasional backpacker, whereas it would help an avid backpacker avoid hundreds of dollars in map-printing expenses. And a single printed map for a short weekend trip will be lighter than an electronic device, whereas a set of printed maps for a 2-week trip could be heavier.
Normally I embrace technology and I’m far from a Luddite, but I think that being “old school” is generally better in the backcountry, which lacks the infrastructure to support a technology-dependent existence, e.g. outlets and connectivity.
1. Paper overview maps
This map type is most useful when planning a trip. I use it to lay out my general route, take note of alternates, identify resupply options, and work through logistics like travel and permits.
In the field, overview maps are useful for pinpointing distant landmarks, having mid-trip planning discussions, and bailing off the intended route. On their own, they may be sufficient for itineraries with on-trail travel only.
Overview maps can be purchased or custom-made. For many of my favorite backpacking destinations, I use a recreation map from National Geographic Trails Illustrated. The Sequoia-Kings Canyon National Park Map (#205), for example, covers the entire park on a 37.5 x 25.5 inch double-sided sheet at 1:80,000 scale with 100-foot contour intervals. Other popular recreational map-makers include Delorme, Tom Harrison, Earthwalk Press, and Green Trail Maps. Because these commercial maps are revised regularly, I can be reasonably confident that they are accurate.
When recreational maps are unavailable, I create custom small-scale maps based on the USGS 30- x 60-minute or 250k series, using online platforms discussed below. These maps are not updated regularly (many are 25+ years old) and they do not include all the details that the commercial maps usually do, like official trails, designated campsite locations, and visitor services.
2. Paper detailed maps
To navigate off-trail, or even just to precisely follow my location when on-trail, maps depicting the landscape in greater detail are useful, if not necessary. In the US, the gold standard for topographic maps is the 7.5-minute quadrangles (“quads”) produced by the United States Geological Survey (USGS).
Each quad — of which there are about 55,000 — represents 7.5 minutes of latitude and 7.5 minutes of longitude. (In this instance, “minutes” are not in reference to time. There are 360 degrees of longitude and latitude. Within each degree, there are 60 minutes of lat and long, and within each minute there are 60 seconds.) This equates to about 8.5 miles of latitude (map height) and about 5.5-7.5 miles of longitude (map width), since the physical distance between lines of longitude decreases towards the poles.
The 7.5-minute quads are printed at a 1:24,000 scale, meaning that one unit on the map (e.g. one inch) equals 24,000 units in real life. For context, there are 63,360 inches in one mile (5280 feet per mile, 12 inches per mile) so one inch on the 7.5-minute maps equals 0.3788 miles. The standard contour interval is 40 feet.
The USGS was not always consistent in its units or contour intervals, however. For example, some maps of the High Sierra are metric: meters instead of feet, and 20-meter contours (66 feet) instead of 40-foot contours. Elsewhere, maps of Wyoming’s Tetons have 80-foot contours and maps of Michigan’s Porcupine Mountains have 5-foot contours.
Pre-digital, printed USGS quads were available directly from the USGS and through local retailers. At a specialty outdoor retailer, you may still find a wooden bureau with short drawers filled with paper maps of local areas. Now, we fortunately have online mapping platforms like CalTopo (my favorite) and AllTrails (also very useful), which offer multiple topographic layers (e.g. 7.5-min USGS, Landsat, Trails Illustrated), plotting tools, GPS integration, and custom mapset exporting.
To be field-ready, digital maps must be exported and printed. Read my tips.
3. Digital maps on a GPS unit
With very few exceptions, I have managed perfectly well with paper overview maps and paper detailed maps. These exceptions, however, can be in fairly dire circumstances. For example, last summer in Sequoia-Kings I led a nighttime descent off Lucy’s Foot West to Lake Reflection, which is 2,500 vertical feet of sustained Class 2/3 terrain. Last spring I spent three weeks in the canyons of southern Utah, many of which have precise access points. And on one of my first guided trips, we bailed out of the Alaska Range and ended up over 100 miles away from our intended exit point.
So for additional precision or additional topographic information when my trusty paper maps, magnetic compass, and altimeter watch are insufficient, I carry with me digital maps stored on a GPS unit.
My preferred GPS unit is my smartphone, not a conventional handheld device like the Garmin eTrex 30 GPS. With a mapping app like GaiaGPS (my pick), BackCountry Navigator TOPO GPS, or Backpacker GPS Trails Pro, my smartphone offers all the features you’d expect of a standalone GPS unit like location identification, waypoint marking, point-to-point navigation, and route tracking.
But a smartphone GPS is even better:
- No extra weight, since I never leave my phone in my car at a trailhead;
- Little additional expense, since I already own the phone and just need software;
- A bright and super high-resolution 5-inch touchscreen;
- Access to topographic map and imagery layers that are far superior to the primitive proprietary layers found on handhelds; and,
- A huge amount of internal memory so that I can download maps along my route plus adjacent maps, in the event that I get off my printed detailed maps due to a detour or unplanned exit.
The only drawback of using a smartphone as a GPS unit is its inferior battery life. If left in airplane mode and used only occasionally, I can do a one-week trip without needing a recharge. But if used more regularly, for a mid-trip charge I must bring my Anker PowerCore+ mini Portable Charger plus the mini USB charging cable. On Guthook Hikes! I recently read an article about the battery life of phones when used as a GPS unit.
What maps and tools do you carry and most heavily rely on when backpacking? Do you have any other map tips to share that were not covered?