# How to measure trail slope without an expensive clinometer?



## SWriverstone (Sep 3, 2009)

I'd like to measure the slope of sections on local trails...but I don't want to fork out $$$ for a nice Suunto Clinometer (or other equivalent). Also, using contour lines on a topo map probably wouldn't work since some of the hill sections I'd like to measure might only be 30-50' long...

I know you can whip up a cheapo, DIY clinometer with a protractor and a weighted string...but is this accurate enough to measure the slope of a trail? (Extreme accuracy probably isn't needed...I just want to be able to figure out if a certain hill is a 5% grade or a 12% grade.)

Would the Suunto clinometer be that much more accurate than the DIY protractor?

Finally, any tips on how best to measure? (For example, I'm guessing you'd want to stand at the bottom of the hill and sight a point at the top of the hill that's the same height above ground as your eye, right?)

Thanks,
Scott

PS - I'm also guessing that using the barometric altimeter in my Garmin GPS isn't very accurate either...but maybe I'm wrong?


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## cjohnson (Jul 14, 2004)

*phone app?*

seems to me there a was post on this forum regarding a free phone app that was able to measure slope.


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## cjohnson (Jul 14, 2004)

*this thread*

http://forums.mtbr.com/showthread.php?t=587727&highlight=phone


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## Trail Ninja (Sep 25, 2008)

I've used the protractor method for years to build trails. Works for me.

... and yes, your guess for measuring is correct. Try a stick with a piece of flagging tape at eye level to sight to. You can carry it around and set it up anywhere so you don't have to find a convenient tree.



> (For example, I'm guessing you'd want to stand at the bottom of the hill and sight a point at the top of the hill that's the same height above ground as your eye, right?)


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## hazdxb (Oct 11, 2008)

If you have an iphone or an ipod go to itunes store and search for "advanced inclinometer" it costs .99 and will get you a nice reading, if you need more accuracy search up "advanced level and inclinometer" which costs 1.99 both are pretty good.


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## bweide (Dec 27, 2004)

IMO A protractor clinometer has more than sufficient accuracy for trail work when considering how inaccurate the human eyeball is. I am an experienced trail designer and my eyeball estimates are often off by 4%. I have trained groups to measure grades with protractor clinometers on slopes I had carefully measured with a clinometer and the students usually get grade measurements that vary only by 1-2% from my own. 

It is easiest to measure grades if you have someone serve as your sighting pole. When I am by myself I will take a trekking pole and determine where on the pole is eye level when kneeling. Then I just have prop up the pole and take my sights from a kneeling position.


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## Trail Ninja (Sep 25, 2008)

bweide said:


> It is easiest to measure grades if you have someone serve as your sighting pole. When I am by myself I will take a trekking pole and determine where on the pole is eye level when kneeling. Then I just have prop up the pole and take my sights from a kneeling position.


Saves a lot of running up and down if you have help. I prefer to mark the sighting stick standing otherwise I can't see over the ferns.


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## slocaus (Jul 21, 2005)

Trail Ninja said:


> Saves a lot of running up and down if you have help. I prefer to mark the sighting stick standing otherwise I can't see over the ferns.


Yes, standing. :thumbsup:

This is in dense chaparral with poison oak, blackberry vines, coyote brush, sage, and coffee berry. It is just a mile to the Pacific Ocean, so you are seeing wet drippy fog. Most of the day the brush was 5-6 feet deep, and at times 12-15 feet deep. We use a 5 foot PVC pole with one end painted florescent orange, as you see in the picture. We site pole to pole with a clinometer. We work with four us us with poles and two of us with a clinometer. You could do the same with protractors.


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## Skookum (Jan 17, 2005)

i'm currently borrowing one, that saves me a ton of cash.


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## mtbikernc69 (Mar 23, 2004)

Seems like dropping $130 for a good quality Clinometer is a good deal and great investment. You really can't beat the quality and durability of a quality tool. I know. I spent 20 years as an auto mechanic and can tell the difference in quality between Craftsman and Snap On/Mac/Matco tools. Whatever money you would save in buying Craftsman tools you lost in gas driving to Sears a dozen times a month to replace sockets and wrenches. You may pay $50 for ONE Snap On wrench but when you wear it out in 20 years and they replace it for free...:thumbsup:


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