ENTS, The Brunton looks like it would be a little easier to use, at least for a beginner. Not that the Suunto is at all hard to use.
JP On Jan 6, 12:18 am, "Edward Frank" <[email protected]> wrote: > Steve > > As far as I know nobody has ever compared the two here in ENTS. Brunton > makes top of the line compasses/clinometers for geology work. would thin > they would make good clinometers. The thing to check would be how easily the > readings are to take, how closely can you estimate the angle, and if you > sight the same point several times from the same position (sight, drop it > down, sight again, do you come up with the same readings. > > You can test the accuracy of the clinometer calibration: > > Ed Frank wrote (Sept 14, > 2005)http://www.nativetreesociety.org/measure/instrumentation/suunto_clino... > > You can test the level accuracy of a clinometer or instrument. Sight from a > marked height at some object- tree of pole at a distance. Have an assistant > mark the point on the distant object the clinometer or instrument says is > level. Move to that spot and sight back to your original position. If it > is perfectly accurate the backsight will be right on the point you shot from > originally. If it is reading high, then the angle it is off will be > under-reading by arc tan [1/2 (error)/distance]. If it is pointing lower > than the starting point, then it is reading high, calculations are the same. > In this way you can tell at least if the original level line is actually > level or not. > > There is no reason to think that the Brunton would be calibration error would > be any different from that of the Suunto. But you can use this process above > to develop a correction factor if you want. The error in the clinometer is a > simple mechanical one relating to the weight placement on the dial. It is a > simple error that should be exactly the same amount in the same direction at > all angles, unlike systematic errors which increase over a range. However > unless the clinometer is really way off, several degrees, then the errors at > the bottom (slightly larger but shorter distances, ad the errors at the top > slight ly smaller but longer distances) tend to pretty much cancel out > > John Eicholz wrote (Nov 6, > 2003)http://www.nativetreesociety.org/measure/instrumentation/calibration.htm > I think I can prove mathematically that the error in tree height that > results from each degree of clinometer error is approximately between > 1.75% and 1.9% of the horizontal distance to the trunk...Because the > factor: (1/cos(@))*(Sin(@)-sin(@+e)) is nearly a constant! Its range is > a smooth progression from 1.74% at 0 degrees to 1.9% at 80 degrees. > > Ed Frank > > http://nature-web-network.blogspot.com/http://primalforests.ning.com/http://www.facebook.com/profile.php?ref=profile&id=709156957 > > > > ----- Original Message ----- > From: Steve Galehouse > To: [email protected] > Sent: Tuesday, January 05, 2010 11:09 PM > Subject: Re: [ENTS] Suunto vs. iPhone > > I have, and have been using, a Brunton clinometer rather than a > Suunto---any appreciable differences in quality or accuracy? > > > Stevehttp://nature-web-network.blogspot.com/http://primalforests.ning.com/http://www.facebook.com/profile.php?ref=profile&id=709156957- > Hide quoted text - > > - Show quoted text -
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