Mile Measurements on the AT

[KilroyWasHere]

Hi Everybody,

Just curious, are miles on the AT measured by a measuring wheel these days or by GPS? More specifically, is all the walking on switchbacks part of that measurement or are switchbacks measured as the crow flies?

Thanks in advance

[Gambit McCrae]

The trail is measured as the trail wonders, not as a crow flies. I am almost sure that it has or is measured by wheel and GPS as well, depending on who is doing the measuring. I would say that it is one of the most accurate trail mileages out there. I know that when I carried GPS on parts of the BMT that my results were was off from the data books...Like, miles off along the lakeshore trail

[moldy]

It's the wheel. I have encountered them several times. I do think that they cheat in the AMC. Those quarter of a mile signs around all the huts are more like a half mile.

[TNhiker]

I would say that it is one of the most accurate trail mileages out there.

the GSMNP redid their measurements years ago and its quite fascinating how the guy measured them all...

link below....




http://www.smhclub.org/Stories/Lochbaum.htm

[Odd Man Out]

I've seen this discussed before. I'm not sure what the OP was meaning by "as the crow flies" since with high enough resolution, a GPS track can measure every twist and turn of the trail as one would with a wheel. However the other thing that people have asked is does a GPS track take into account the additional mileage due to elevation gain and lost. The answer is that it doesn't really matter as much as most people think. You can estimate the difference with geometry. Compare two hikers. One hikes 10 miles a path that is perfectly flat (horizontal) straight line. The other hiker also hikes to a point that is 10 miles away (on a horizontal line). He also hikes a perfectly straight line, but follows the contours of hills up and down which adds some extra distance. If we assume the incline up and down is always on a 10% grade (I use 10% because I recall reading somewhere that the AT averages 10% grade over the length of the trail, but that could be wrong. I think MapMan measured it once), you can use geometry to calculate that the first hiker hikes exactly 10 miles and the second hiker hikes 10 miles plus 263 feet, which over 10 miles isn't much. Over a 2000 mile trail, the difference is only about 10 miles. From the point of view of a cartographer, it is in interesting questions. From the practical point of view for the hiker, the difference isn't particularly relevant, unless you are taking a bee-line hike from the summit of El Capitan to the bottom of Yosemite Valley.

[Malto]

the GSMNP redid their measurements years ago and its quite fascinating how the guy measured them all...

link below....




http://www.smhclub.org/Stories/Lochbaum.htm

I very thankful there are people as dedicated as this guy in the hiking community.

[AllDownhillFromHere]

Avery supposedly wheel-measured the whole thing back in the day.

[TNhiker]

Avery supposedly wheel-measured the whole thing back in the day.

yeah....i believe he did...

but, the trail has changed an awful lot since then...

[Sarcasm the elf]

Avery supposedly wheel-measured the whole thing back in the day.

yeah....i believe he did...

but, the trail has changed an awful lot since then...

If I recall, there is a story that the original trail (since rerouted) carved a particularly grueling path up a steep mountain in the South the name of which escapes me. The route as supposedly flagged as a joke by the trail builders because they wanted to see of Avery and his wheel could make their way up the darn thing.

[Grampie]

Hi Everybody,

Just curious, are miles on the AT measured by a measuring wheel these days or by GPS? More specifically, is all the walking on switchbacks part of that measurement or are switchbacks measured as the crow flies?

Thanks in advance

Around 2000, +- a year I met a group of four hiking up Stratton Mountain on the AT in Vermont. I remember one of their names. It was Dr, Dell. One of the hikers was carrying a large devise on his back that was what I would think was some kind of GPS unit. They told me that they were doing a satellite map of the trail. They had a support vehicle that would meet them at road crossings. They would than relay the info that they collected, by downloading it by phone. They were doing this to establish accurate measurement of the trail.
They were doing this before todays small GPS units and cell phones were in common use.
Some years later I saw an article about the project and that Dr. Dell had passed away.

[AllDownhillFromHere]

Around 2000, +- a year I met a group of four hiking up Stratton Mountain on the AT in Vermont. I remember one of their names. It was Dr, Dell. One of the hikers was carrying a large devise on his back that was what I would think was some kind of GPS unit. They told me that they were doing a satellite map of the trail. They had a support vehicle that would meet them at road crossings. They would than relay the info that they collected, by downloading it by phone. They were doing this to establish accurate measurement of the trail.
They were doing this before todays small GPS units and cell phones were in common use.
Some years later I saw an article about the project and that Dr. Dell had passed away.

That was Deldoc! I met him in 1999, somewhere in the mid-Atlantic. Backpack mounted GPS unit.

[gpburdelljr]

Since GPS data is now available for the entire trail, I would assume that current trail measurements are based on GPS. GPS measures horizontal distance, not slope distance.

[AllDownhillFromHere]

Deldoc info:
http://www.xyht.com/spatial-itgis/ma...-trail-part-2/

[Odd Man Out]

Avery supposedly wheel-measured the whole thing back in the day.

There's a photo of him with his measuring wheel in the Appalachian Trail book.

[Venchka]

There’s a sign at each end. Does it really matter how far apart those two signs are?
Wayne

[tdoczi]

There’s a sign at each end. Does it really matter how far apart those two signs are?
Wayne

when discussing the theoretical difference due to elevation change not being incorporated, no.

if, as the OP was asking, the measurements excluded accurately measuring the switchbacks.... well yeah, a 2200 mile trail that was actually 2600 miles might be an issue.

[Venchka]

when discussing the theoretical difference due to elevation change not being incorporated, no.

if, as the OP was asking, the measurements excluded accurately measuring the switchbacks.... well yeah, a 2200 mile trail that was actually 2600 miles might be an issue.

The AT has been around long enough to have a decent idea of the gap between the two end points.
Asking if switchbacks are included in the total distance is.......
Y'all have fun.
Wayne

[tdoczi]

Asking if switchbacks are included in the total distance is.......

on one hand i agree totally. on the other, as dumb as it is, it does seem like some maps of some trails are measured in ways that dont include the walking length of the switchbacks in the total mileage.

or maybe people who insinuate such things arent correct. i dont know. but at a minimum there is chatter to that effect.

[Pondjumpr]

To answer the question more specifically, than it has already been answered.... As the crow flies, it is right at 1,117 miles, or just over half of the actual mileage taking into account for the "switchbacks." Credit Google maps for the measurement.

[Odd Man Out]

To answer the question more specifically, than it has already been answered.... As the crow flies, it is right at 1,117 miles, or just over half of the actual mileage taking into account for the "switchbacks." Credit Google maps for the measurement.

Yes it all depends on the resolution of the measurements. The coastline paradox states that if you make enough measurements, the distance of a highly convoluted path can approach infinity. No wonder hiking the AT is so hard. https://en.wikipedia.org/wiki/Coastline_paradox