Map miles vs. actual miles

[timcar86]

I'll be making a trip from Clingman's Dome to Fontana Dam in April. I have an argument with my friend that says due to elevation change, we'll be walking more like 60 miles instead of 30. So what's the deal? I plan on spending 3 days on the trail and I expect to make it in that time. I realize that the hike will be strenuous and I've been training for it. Is 30 miles in 3 days unrealistic?

[Lone Wolf]

it's 32 miles. not 60. yes you can do it easily in 3 days.

[_terrapin_]

AT distances, as listed in the guidebooks, are distance-over-ground.

Furthermore, in spite of appearances, the verticals don't add much to the distance. Eg, what most thru-hikers would consider an "extremely steep" grade is typically no more than 20% -- ie., 1000 feet of gain in 1 mile. A more typical grade is 1/2 or 1/3 of that.

The profiles shown on the ATC maps generally have enormous vertical exaggeration. 5 to 1 is common, and sometimes it's higher.

[Wise Old Owl]

AT distances, as listed in the guidebooks, are distance-over-ground.

Furthermore, in spite of appearances, the verticals don't add much to the distance. Eg, what most thru-hikers would consider an "extremely steep" grade is typically no more than 20% -- ie., 1000 feet of gain in 1 mile. A more typical grade is 1/2 or 1/3 of that.

The profiles shown on the ATC maps generally have enormous vertical exaggeration. 5 to 1 is common, and sometimes it's higher.

Doesn't hold true when you are not on the AT, there have been times where the GPS says .6 back to the lot and a wooden sign says 1 mile!

[Johnny Thunder]

I'll be making a trip from Clingman's Dome to Fontana Dam in April. I have an argument with my friend that says due to elevation change, we'll be walking more like 60 miles instead of 30. So what's the deal? I plan on spending 3 days on the trail and I expect to make it in that time. I realize that the hike will be strenuous and I've been training for it. Is 30 miles in 3 days unrealistic?

HAHAHAHAHAHAHAHAHAHAHAHAHAHAHA

This has been a pet peeve of mine since I first took my orientation merit badge courses. Geometry tells us that the airial distance shown in maps is incorrect when it comes to the actual mileage of terrain due to changes in elevation.

Funny thing is that I seriously just had this conversation on Friday night with a guy who worked for Google maps. He confirmed that maps were inherently wrong when it came to actual distance. The GMaps project takes GPS distance and elevation readings something like every 5 yards (Friday was a bit hazy). After that it uses these readings to calculate the actual distance you've traveled.

He imagined that when a mapmaker publishes a map that the distances listed are actual distances and not map distances.

Hope that makes sense.

I wouldn't think that you'd be traveling 60 miles over 30...that seems like a lot. See if you can add up the total number of feet gained and the number of feet lost in elevation. Then use that figure as the vertical for figuring out the hypotenuse (spelling?) of the triangle.

[_terrapin_]

See if you can add up the total number of feet gained and the number of feet lost in elevation. Then use that figure as the vertical for figuring out the hypotenuse (spelling?) of the triangle.

When you do that, you'll see that the error is fairly small, typically on the order of 5%. In any case, the distances cited in the AT data books are accurate. They're measured with a wheel. They're distance-over-ground.

[Johnny Thunder]

When you do that, you'll see that the error is fairly small, typically on the order of 5%. In any case, the distances cited in the AT data books are accurate. They're measured with a wheel. They're distance-over-ground.

Exactly...1000 feet of elevation loss/gain only tacks on an extra 93 feet of walking over the course of a map mile.

[Rain Man]

The Pythagorean theorem states that the square of the hypotenuse is the sum of the squares of the other two sides, that is,

c2 = a2 + b2 (those "2s" should be superscripted)

If he says you're traveling 60 miles up and down over a 30 mile "base line", then 60 squared equals 30 squared plus "x" squared. "X" being your rise (and fall). You should be able to calculate it as two equal back-to-back triangles, to allow for equal rise and fall for a rough calculation.

If my math is correct, you'd have to climb (and/or descend) 52 vertical miles from Newfound Gap to Fontana Dam in order to travel 60 "straight line" miles.

I don't think so. People who ascend Mt Everest climb less than 5 miles.

BTW, fat old ME did the Fontana-to-Newfound Gap hike NOBO in two and a half days, so I sure bet you can do it SOBO in three, for sure.

RainMan

.

[Beachcomber]

The Pythagorean theorem states that the square of the hypotenuse is the sum of the squares of the other two sides, that is,

c2 = a2 + b2 (those "2s" should be superscripted)

If he says you're traveling 60 miles up and down over a 30 mile "base line", then 60 squared equals 30 squared plus "x" squared. "X" being your rise (and fall). You should be able to calculate it as two equal back-to-back triangles, to allow for equal rise and fall for a rough calculation.

If my math is correct, you'd have to climb (and/or descend) 52 vertical miles from Newfound Gap to Fontana Dam in order to travel 60 "straight line" miles.
.

Never did cotton to that book-larnin' no-how. We're out in the woods so we won't have to do math OR spelling.

[bencarlinson]

There is a difference will be there between the map and actual miles. Map are used mainly for directional signs and simultaneously distance about the area also. A treasure map is drawn to a scale of 2 inches = 3 miles, like-wise different types of maps are available according to the needs and specification areas also. Please produce some more attachments about the topic for view detail information.

[timcar86]

That's good to hear, I'll send him this page.

[Appalachian Tater]

In other words, the distance measured between two points on a map is less than the distance listed in the guidebooks. And when Google maps gives directions and milage it takes this into account as well?

[Slo-go'en]

In other words, the distance measured between two points on a map is less than the distance listed in the guidebooks. And when Google maps gives directions and milage it takes this into account as well?

Figuring out distances from maps using a ruler gives you the straight line distance between points, which is fine if the path between those two points is indeed a straight line - which it rarely is.

Therefore, to know what the exact distance between those points are, someone would have had to physically measure the distance on the ground. Which has been done for all roads and major trails. This actual measured distance is often marked between selected points on maps.

No doubt google maps has access to the measured distance data base and uses that when calculating distance for directions.

[snick]

Figuring out distances from maps using a ruler gives you the straight line distance between points, which is fine if the path between those two points is indeed a straight line - which it rarely is.

Therefore, to know what the exact distance between those points are, someone would have had to physically measure the distance on the ground. Which has been done for all roads and major trails. This actual measured distance is often marked between selected points on maps.

There are problems with maps that depict three dimensional surfaces on a hlat surface, and there is also a problem with scale and the relationship between the line on a map and the trail in the woods. If you are scaling distances on a map and the map has a large scale, then you are missing many of the small curves that are on the ground. I was surprised to see that the A.T. has been measured with a wheel. I guess that it was a way for someone to get paid to take a vacation. Wheels are inherently inaccurate, because the wheel doesn't measure all of the surface; it only measures what it has touched.


I doubted the accuracy of A.T. map distances from day one, but I realized that such impressions are rather subjective. Then I noticed that some sections agreed with my impression, and those pieces were straight and even. Then there was the day in Connecticut when it took me five hours ttravel 2.8 miles, and the next day was worse: it took me more than an hour to cover 0.3 miles. That's 1584 feet; I can throw a stone almost a fifth of that distance, and it took me an hour to walk it. The map distances are just wrong.

[Pedaling Fool]

There are problems with maps that depict three dimensional surfaces on a hlat surface, and there is also a problem with scale and the relationship between the line on a map and the trail in the woods. If you are scaling distances on a map and the map has a large scale, then you are missing many of the small curves that are on the ground. I was surprised to see that the A.T. has been measured with a wheel. I guess that it was a way for someone to get paid to take a vacation. Wheels are inherently inaccurate, because the wheel doesn't measure all of the surface; it only measures what it has touched.


I doubted the accuracy of A.T. map distances from day one, but I realized that such impressions are rather subjective. Then I noticed that some sections agreed with my impression, and those pieces were straight and even. Then there was the day in Connecticut when it took me five hours ttravel 2.8 miles, and the next day was worse: it took me more than an hour to cover 0.3 miles. That's 1584 feet; I can throw a stone almost a fifth of that distance, and it took me an hour to walk it. The map distances are just wrong.

Dude, you can argue all you want about errors introduced in maps by various factors, but your examples are not map errors. Sounds like you just slipped into another dimension, happens all the time, just be happy that you somehow managed to slip back into this dimension. http://criticalbelievers.proboards.c...nt&thread=2570

[tdoczi]

Wheels are inherently inaccurate, because the wheel doesn't measure all of the surface; it only measures what it has touched.

ok, i was really trying to avoid asking this, but what the heck does that statement even mean exactly?

[snick]

That means that wheels can't be trusted to measure anything except for a flat surface, no bumps and no depressions.

[Montana]

Wheels are inherently inaccurate, because the wheel doesn't measure all of the surface; it only measures what it has touched.

Exactly... If you had a microscopic wheel to measure with, the distance from GA to ME would be nearly infinite!

[hopefulhiker]

One thing you have to consider is the little bit of extra walking you do to get to a water source or to get to a town....

[Johnny Thunder]

Also, those 30 miles might "feel" more like 60 if you compared them to the 30 miles in Maryland....or 30 miles in Ohio. Maybe it's just me and I'm out of shape...