Backcountry Navigation with Incomplete or Out-of-Date Maps

The United States Geological Survey stopped sending field observers to verify and update the location and existence of recreational trails, power lines, rail lines, pipelines, remote roads, campgrounds, and property boundaries by 1990. As a result many backcountry maps have out-of-date and incorrect information. The USGS map shown here shows a hiking trail which closed by 1950 and a town which disappeared in 1918. The new USGS National Map published in 2009 doesn't display any of these entities.

It's important to understand the limitations of incomplete or out-of-date maps for backcountry navigation since so many mapping applications, GPS units, and GPS-enabled smartphone apps are built around them. It's not just old maps that are full of errors and out of date-information, but also crowd-sourced map layers that assemble observations from multiple contributors without good editorial standards or field verification.

Despite these map quality deficiencies, expert wilderness navigators have developed techniques to make good backcountry navigation decisions and avoid getting lost. What strategies do they use to plan routes, identify mapping discrepancies, stay found in the field, and reach their navigational objectives?

The Limitations of Map Accuracy

If you thought that backcountry mapping data would be accurate and complete in this day and age, you're in for a big surprise. It's not, in large part because the USGS (United States Geological Survey) stopped sending field observers to verify non-topographic features such as roads, recreational trails, pipelines, powerlines, mountain peak labels or elevations, pubic buildings and structures, railroads, remote roads, campgrounds by 1990 due to budget constraints. The new National Map which started coming out in 2009 has none of these features, so you have to rely on 50's-era historic USGS maps, even if they're out of date.

What kind of information is missing, out-of-date, or incorrect on older USGS maps or current backcountry maps produced by third parties?

• Maps leave out information useful for route finding such as property lines, old roads, ski trails, snowmobile trails, power lines, and are often quite activity-specific for hiking, mountain-biking, skiing, etc. rather than general purpose.
• Maps capture a snapshot in time and are often considerably out of date due to changes to the physical landscape caused by avalanches or floods, bridge washouts, trail closings, road construction, business closings, etc.
• Maps don't reflect local weather patterns, snow coverage, avalanche danger, water levels, drought conditions, fire conditions, forest coverage, or vegetation density which can all throw a serious wrench into your intended route.
• Map scale may be too abstract (for example the 1:100,000 scale maps provided with many GPS units) to provide enough information to make good route decisions for foot-travel.

My map drawer: I use multiple maps whenever I plan off-trail trips and collect new ones that might be relevant for my area since they contain different information.

Expert Navigation Strategies

Expert navigators use three core strategies to cope with incomplete, out-of-date, and incorrect maps during the planning and travelk phases of backcountry trips.

1. Gathering map and route information from multiple sources, including historical sources
2. Knowing how to stay found by following landforms, often called handrails.
3. Taking the most energy-efficient route to a destination.

Gathering Maps and Route Information from Multiple Sources

When planning routes, it's good to collect route information from multiple sources. One strategy is to collect different paper maps, including activity-specific maps for hiking, skiing, or snowmobiling. Knowing that you're likely to come across a snowmobile trail, can be a good clue about your location if you don't have or use a GPS. That same trail can provide an easier route than plunging off-trail into dense vegetation or deep snow if it goes in the direction you want to go.

In addition to paper maps, many online planning tools such as Caltopo.com and Hillmap.com include free maps, historical maps, and satellite imagery that you can use to plan routes. They also let you superimpose them on top of one another, called layering (illustrated below), which is useful for combining them into a single composite view.

Local trip reports published online by other hikers, online discussion groups, weather forecasts, regional weather patterns, fire history, river gauges and avalanche forecasts can also provide valuable information for planning routes.

An example of two overlaid maps: Google Maps is overlaid with crowd-sourced hiking trail routes from the OpenStreetMap using the Caltopo.com online mapping tool.

Knowing How to Stay Found by following Landforms

One of the marks of an expert navigator is defining and using routes that follow obvious terrain features, often called handrails. This is a good fall-back strategy when roads or existing trails don't head in the direction you need to walk or you don't know about them. Handrails include rivers, streams, mountain passes, ridgeline, and other easy to follow landforms that make it possible to know where you are with reasonable certainty.

It also means that you don't have to constantly check your a GPS or compass to make sure you're on the right bearing. For example, you can hike beside a river, hike through a valley, or climb a ridgeline shown on your map and know where you are as long as you walk adjacent or on that landform. You can link together these handrails with other landmarks like stream crossings or mountain summits to form easy to follow routes and always know where you are.

Some handrail examples: Hike along the river on what looks like an old forest road until you come to a stream, then head south up the ridge to the summit of Bald Peak.

Taking the Most Energy Efficient Route

A third navigation strategy use by expert navigators is the notion of energy efficiency, or following the route that uses the least amount of energy to get to your destination. If you watch animals in the wild or come across game trails, you'll see that they take the easiest route to get from one place to another.

This strategy is especially relevant for GPS unit or GPS-smartphone app users, since an as-the-bird-flies route plotted from one waypoint to another by a GPS device is often not the most energy-efficient route to take.

If your map(s) depicts hiking trails, logging roads, forest service roads, or powerlines, they can be the most expeditious way to get from one point to another. But in their absence, you need to fall back on heuristics about different landforms, whether they're easy to follow, or whether they should be avoided.

For instance, certain landforms are not easy to hike along or traverse, such as stream gullies which fill up with dense vegetation or crossing steep slopes which are to contain fallen trees and rock debris. Hiking around these obstacles rather than picking your way through them is much easier, faster, and safer.

Wrap Up

Becoming a good backcountry navigator takes practice, especially because you'll usually be using maps that have inaccurate or out-of-date information. Knowing how to obtain and assemble different mapping sources; understanding what's information is accurate, what's missing, and what's probably out of date; and how to navigate efficiently in the field using natural features; are all the marks of an expert navigator.

It doesn't matter if you hike, bike, backcountry ski, or hunt or if you use a compass, GPS unit, smartphone app to follow a route, incomplete and out-of-date maps are the norm and here to stay. Learn how to find your way across the landscape despite them and you'll be self-sufficient.

from Section Hikers Backpacking Blog http://ift.tt/2ihpgSO