Map, Compass & GPS

Map, Compass & GPS
Wild flowers along Fall Creek on the way to the Green Lakes - Oregon

Thursday, February 25, 2016

Pace - Measuring Distance in the Backcountry

 Many outdoorsmen measure distance in the backcountry by using a Global Positioning System (GPS) receiver.   GPS receivers are reasonably accurate, real time, and provide distance traveled and distance to a destination.
But what does the hiker do if they don’t have a receiver, the GPS fails or batteries die?
A proven method for estimating distance is known as pacing.  Pacing is not as accurate as the GPS receiver, but it can give a reasonable approximation of the distance traveled.  Together with a map and compass, pacing is an important component of evaluating a hiker’s track through the backcountry.  In darkness or periods of low visibility pacing helps to determine the hiker’s location through a process known as dead reckoning. 
Pacing is a method that begins with measuring one’s stride, with the intent of determining an individual’s length of stride. A pace is a measured two steps; a complete stride.  As illustrated below, every time the right foot hits the ground is one pace. Each pace (two steps) normally measures out to almost 50-60 inches.

Perhaps the best method to determine a hiker’s pace is to record it over a specific distance to determine an average.  Before embarking on the trail, the individual should develop a “pace average” over a controlled area first. 
For example, measure the number of paces for a known distance of 100 yards.  To achieve this, go to a high school foot ball field or track.  Walk along a sideline from end zone to end zone.  Count how many paces it takes to go 100 yards.  Do this eight times and record the total number of paces for each 100 yard event.  Determine the average for all eight 100 yard lengths completed.  The result is that the hiker may determine that the average 100 yard pace count to be 58 ½ paces.  (With children compensate and be mindful of their strides being significantly different, including a skip here and an off trail discovery there.)
Whatever the “pace average” may be, do keep the stride natural and smooth.  Don’t try to exaggerate and unnaturally lengthen the stride.
Don’t get too bogged down in the estimation of the accuracy of the average pace. Of larger importance is to understand the complexity of the terrain and how it will impact stride and a hiker’s “pace average”.   Anticipate strides being different.  Take the time beforehand to imitate a 100 yard course on sloping ground.  Further, try a 100 yard pace in soft soil and hard soil, smooth ground and rocky ground. Move to other locations once an average pace is found on a controlled level environment (football field).  Layout a 100 yard course on sloping ground. 
Pacing over long distance can become quite boring and the hiker easily distracted.  This is especially true when the pace count is in the hundreds.  Was that pace 545 or 554?  In such cases pacing beads may be a useful tool.  Pacing beads can be purchased from online venders or made at home using paracord and simple beads. 
 
A quick Google search will turn up several methods for using pacing beads.  For example, Wikipedia states that “As users walk, they typically slide one bead on the cord for every ten paces taken. On the tenth pace, the user slides a bead in the lower section towards the knot. After the 90th pace, all 9 beads are against the knot. On the 100th pace, all 9 beads in the lower section are returned away from the knot, and a bead from the upper section is slid upwards, away from the knot.”
Pacing beads can be an important asset when Dead Reckoning (known as DR) with a map and compass.  Vigilant compass sighting and a steady “pace average” helps provide a rough approximation of both distance and direction when moving through the backcountry.







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