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sketchfest

calculating degress

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If someone says, "Oh damn that trail was steep, our elevation gain was 520' per mile." Is there a method to calculate the average gradient of that trail that would equate to 45, 50 or whatever degrees?

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Yeah, I will have to get a copy of my third grade math book to figure that one out.

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Take the angle of the slope, and convert it to radians (which means

take the slope angle in degrees, divide it by 180.0, and multiply it by pi=3.14159...). Next, compute the tangent of the slope angle (where the angle is in radians). Use the "tan" button on your scientific calculator for this. Next, multiply the result by 5280.0. The result is the number of feet by which the slope will rise, over the course of a mile of flat distance (i.e., as might be measured by a GPS).

 

For small slope angles, you can probably just approximate calculating the tangent tan(x) with x - (x^3 / 3), where again, x is the slope angle in radians.

 

 

Edited by Stephen_Ramsey

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If you've got a scientific calculator - Divide the elevation change by 5280. Take the AntiTangent of this (usually Tan-1 - or with the windows calculator, click the inverse button) - this is the measure in degrees of your slope (in the case you mentioned 5.62 degrees)

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way simpler method

 

tangent = rise/run

 

so in your example 520'/1mile (5280 or whatever) (way simpler in metric!!!!)

 

so tan x = 0.1

 

so x = inv. tan of 0.1

 

I never have to do that last part cause i use % slope and it's a 10% slope.

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you stupid fuckers. that angle equals inverse sine of the ratio of elevation gain over trail length. you aint measuring 'run' you measuring the hypotenoos shit. rolleyes.gifpitty.gifmoon.gif

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i was a minnit too slow there all righty

 

hey lum ox iof you measure the trail length off a map then it IS horizontal distance. dont gimme no inverse sine.

 

of course if you took trail length out of a sissy hiking book where it was measured with a wheel they push along da trail THEN maybe youd be making sine but they probably already did the froo froo slope calc for ya......

 

ANYWAYS its all just chestbeating...... the RELENTLESS mt si trail storms upward at an average angle of 19.7 degrees, STEEPER THAN MT OLYMPUS THE HIGHEST MOUNTAIN IN THE SOLAR SYSTEM yellaf.gif

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Stephen_Ramsey said:

Take the angle of the slope, and convert it to radians (which means

take the slope angle in degrees, divide it by 180.0, and multiply it by pi=3.14159...). Next, compute the tangent of the slope angle (where the angle is in radians). Use the "tan" button on your scientific calculator for this. Next, multiply the result by 5280.0. The result is the number of feet by which the slope will rise, over the course of a mile.

 

For small slope angles, you can probably just approximate calculating the tangent tan(x) with x - (x^3 / 3), where again, x is the slope angle in radians.

 

 

yellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gifyellaf.gif

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sketchfest said:

If someone says, "Oh damn that trail was steep, our elevation gain was 520' per mile." Is there a method to calculate the average gradient of that trail that would equate to 45, 50 or whatever degrees?

 

No. rolleyes.gif

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The steepest hiking trail to date I've ever been on is the Lake Constance trail. Since I was an english major and suck at calculus someone calculate this one. 3400 vert ft in 2 miles!

 

BTW, it's degreEs, not degress!

Edited by David_Parker

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17.8 degrees, or 32.2% grade. (assuming dist given is map dist). Actual length of trail (hyp) = 2.1 miles

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IIRC slesse west side trail and rexford trail are both steeper than that -insert chestbeat icon here rolleyes.gif

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i think a degress is something like a negress but steeper pitty.gif

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here's how I calculate it:

 

moderate sweat produced - easy

 

thighs a little rubbery at top - moderate

 

lungs seared - steep

 

all three - too damn steep

 

you guys just love this nerdy stuff. wazzup.gif

 

 

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since you guys love nerdy stuff, can someone explain to the math idiot who couldn't understand half this post what the difference between grade and degrees is? for instance when you see those 6% grade, trucks use caution signs, what is the degree of the slope? and why don't we just use one of these systems (and switch to metric while we're at it)?

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% grade is rise over run times 100. Degrees it arctan rise over run. A 6% grade is equal to 3.4 degrees. for relatively flatter slopes it is easier to perceive % grades. When you are talking a 45 degree slope it doesn't make much sense to call it a 100% slope so you use degrees for steeper stuff.

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aint_this_great said:

since you guys love nerdy stuff, can someone explain to the math idiot who couldn't understand half this post what the difference between grade and degrees is? for instance when you see those 6% grade, trucks use caution signs, what is the degree of the slope? and why don't we just use one of these systems (and switch to metric while we're at it)?

a 6% grade means it goes up (or down) about 6 feet for every 100 feet horizontal distance. thas all.

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Degrees and percent slope are useless. Radians are the ONLY way to go. Ask any physicist.

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Dru said:

way simpler method

 

tangent = rise/run

 

so in your example 520'/1mile (5280 or whatever) (way simpler in metric!!!!)

 

so tan x = 0.1

 

so x = inv. tan of 0.1

 

I never have to do that last part cause i use % slope and it's a 10% slope.

 

and furthermore... tangent = rise/run = percent slope

 

So, if you have a slope defined as , say 14%, then the degree measurement is inv. tan (14) cool.gif

 

Handy reference here.

 

Go here for trig tables if you don't have a calculator. smile.gif

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Sphinx said:

Degrees and percent slope are useless. Radians are the ONLY way to go. Ask any physicist.

rolleyes.gifrolleyes.gifrolleyes.gifrolleyes.gifrolleyes.gif

 

radians are for theorists and guys what wear lab coats instead of hard hats thumbs_down.gif

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Dru said:

, STEEPER THAN MT OLYMPUS THE HIGHEST MOUNTAIN IN THE SOLAR SYSTEM yellaf.gif

 

I think it is called Olympus Mons or some such (on Mars). Mt Olympus is a little closer to home in WA or Greece. wazzup.gif

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