How steep a hill?
April 25, 2007 9:03 PM   Subscribe

Is there a (cheap-ish) tool that will measure pitch (as in a roof, or hill)? and what is it called?

I realize I can do this with a long level and a yardstick, but I have a small project wherein I'd like to measure the steepness of of bunch of roads around town and something that would allow me to run out onto the road and make a very quick measurement would be ideal, as I am not actually being paid inexpensive would be nice as well.
posted by edgeways to Sports, Hobbies, & Recreation (15 answers total)
You dont need a level. Just use a plumb line (make one yourself) and a protractor (cheap plastic one).
posted by vacapinta at 9:07 PM on April 25, 2007

The handheld tool that does this is a clinometer. It's basically a plumb weight and a protractor in a little housing with a sight. They're not super-accurate, and as vacapinta says, you can probably roll your own fairly easily.
posted by flabdablet at 9:11 PM on April 25, 2007

Couple of good looking roll-your-own recipes here.
posted by flabdablet at 9:14 PM on April 25, 2007 [1 favorite]

They make things like this that are meant to be mounted on a bike, which I'm sure you could adapt in some way. Or something like this for aiming a satellite dish. They're all essentially really simple devices, just some kind of pendulum or bubble.
posted by Rhomboid at 9:14 PM on April 25, 2007

Oh and for measuring the grade of a road, I think you would want something with a little bit of length to it (i.e. a few feet) because otherwise you'd be measuring the grade of a very small area, which could vary a lot. Or just take a handful of measurements at a few different spots within say 10 feet and average them.
posted by Rhomboid at 9:16 PM on April 25, 2007

To measure the grade of a road, you'd stand up a pole that has a clearly visible mark on it at your eye height, then sight on the white mark through your clinometer from maybe twenty metres downhill.
posted by flabdablet at 9:29 PM on April 25, 2007

If you're measuring lots of roads, and you don't have a helper, and you reckon you can get an accurate enough measurement based on the relative heights of two spots maybe a couple metres apart, you can make yourself a big A-frame level and add extra calibration marks either side of the central one.
posted by flabdablet at 9:37 PM on April 25, 2007

A clinometer (they're cheap) or a GPS with an altimeter. The GPS is more work but more fun and potentially more accurate.

You could also find topo data on the web somewhere and figure it out from that.
posted by unSane at 9:39 PM on April 25, 2007

also related
posted by LobsterMitten at 10:27 PM on April 25, 2007

You could throw something together in 10 minutes if you have a slide rule.

Attach a plumb line of known length to the top of the slide. Use the angle between the plumb line and the side of the slide to get the ruler level (When they line up, it's level). Then you have a known rise. Put the other end of the ruler into the hill, and the position of the slide in the ruler will give you the run. Take the inverse tangent of rise/run and you have an angle. You could then mark the ruler with the angles even before going out.

Don't some slide rules fold up? Not sure if they become rigid at the joints.
posted by cotterpin at 6:49 AM on April 26, 2007

Cotterpin, the tool you are referring to is a combination square. As in the link, you can get one with a protractor head, which may be what you're thinking of with "fold up."

A slide rule is not a measuring tool; it's a calculator.
posted by Kirth Gerson at 7:40 AM on April 26, 2007

You dont need a level. Just use a plumb line (make one yourself) and a protractor (cheap plastic one).

Note that if you're trying to find the % slope, which is typically the form of measurement used by civil engineers and the like, this method will require trigonometric functions to get from the angle of the slope to the percentage, and the correlation isn't necessarily intuitive, because the percent slope measures rise over run. So a slope that rises as fast as it runs (a 45 degree angle) is 100%.
posted by LionIndex at 7:48 AM on April 26, 2007

To be clear then, the slide rule is not for its markings but only its shape. Any straight edge with a slider would work.
posted by cotterpin at 9:26 AM on April 26, 2007

You didn't click on the links I went to so much trouble to give you, huh?
posted by Kirth Gerson at 10:43 AM on April 26, 2007

Are you sure you want to do it manually? If not, you can robably get a set of topo maps on CD for your state for like $50 (from National Geographic), and then you have both distance and altitude (contour lines) and you are all set...
posted by blindcarboncopy at 8:19 AM on May 14, 2007

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