Gary- Well doesn't that seem counter-intuitive...I'd think that 98.56% of the time this percentage would be most accurate to the last listed digit, and the adjacent (to right) digit not listed was estimated and then rounded to an appropriate digit. Just because you multiply 81.23 by 12.37 and get 1004.8151 from your calculator, assuming that you're correct with an answer to the ten thousandths of a unit, when your instrumentation was only capable of rendering data accurate to the hundredth, is an unsupported extrapolation.
So when the laser rangefinder manufacturer says their product is accurate to .5 meter or .5 yard (under distances less than 100 yards for Nikon 550 Forester), just because you can multiply it by a sine function listing digits to the ten thousandths, doesn't make the ultimate height reading accurate to the ten thousandth of the unit measured. 0.5 meter or 0.5 yard (already an indication of stated inaccuracy by virtue of units not having parity) is the weak link in this chain. The fact that ENTS works to minimize inaccuracies is very laudable, and I'm satisfied that ENTS measurements done by our "A-Team" are as accurate as manufacturers state and only exceeded by 'careful' direct taping measurements. And such efforts should be continued. But the facts remain, at least I propose that to say our laser measurements are accurate to a tenth of a foot begs another question. I propose that there is data out there that will indicate that a tree's height varies diurnally and seasonally between actual growth, respiration/transpiration processes, in a range wider than that of our claims of static height that gets put down in spreadsheets as 'golden'. I suggest that "to the nearest foot" should be more appropriate, and still a challenge to obtain with high levels of statistical confidence. -Don > From: [email protected] > To: [email protected] > Subject: Re: [ENTS] Finishing up in the Trees of Peace > Date: Tue, 8 Dec 2009 11:18:52 -0500 > > EPA assumes the last digit to be interpolated. Therefore if your > least precise measurement is to the nearest tenth then EPA assumes the > hundredth place is an estimate and data should be stated to the > hundredth. > > Gary > > On Dec 8, 2009, at 9:25 AM, Bob <[email protected]> wrote: > > > Lee, > > > > You rascal. You took the bait. Significant digits. Yes, we > > overstate the implied accuracy when we show too many decimal digits. > > One decimal digit is pushing it, let alone two. > > > > In the Air Force on engineering projects, we we're forced to show > > 4 decimal digits on calculations we we're pulling out of private body > > cavities. I wrote a paper on that, but it wasn't especiaaly well > > received by the brass. > > > > Bob > > > > Sent from my iPhone > > > > On Dec 8, 2009, at 8:50 AM, Lee Frelich <[email protected]> wrote: > > > >> Bob: > >> > >> There is no way you can measure a tree to the nearest hundreth of a > >> foot--e.g. 156.05 feet. Please get out your 7th grade math textbook > >> and > >> review the chapter on significant digits. > >> > >> Also, because cold air is denser than warm air, the laser beam goes > >> through it more slowly, thereby over-estimating tree heights on cold > >> days. Therefore, all of the trees you measured are an inch shorter > >> than > >> you reported. In the future, please restrict tree height measuring to > >> days when the temperature is within +/- 2 degrees of the temperature > >> inside the factory where your rangefinder was made. > >> > >> Lee > >> > >> > >> > >> [email protected] wrote: > >>> ENTS, > >>> > >>> Braving a colder than comfortable temperature, I finished > >>> remeasuring > >>> the 150s in the Trees of Peace today - at least I think I have. The > >>> trees in the table below have been measured within the Trees of > >>> Peace > >>> stand, not to include the Mast Pine area. I have a more work to do > >>> there. Plenty of pines have been measured elsewhere, which will be > >>> reported in due course. > >>> > >>> One very important measurement today was the confirmation of the > >>> Mirror Tree as 156.05 feet in height taken at mid-slope. I should > >>> explain. The tree's trunk is partly buried. Will Blozan and I > >>> measured > >>> it a few seasons ago and projected the location of its true base. It > >>> was a provisional 156 then. Today I dug down at mid-slope location > >>> and > >>> took a new mid-slope spot as the base, although I still had not > >>> reached the root flare. However, the new mid-slope basal position is > >>> sufficiently low to allow a 156.05-foot measurement. The tree's true > >>> base is farther down. How much? Maybe another 0.5 to 1.0 feet. I > >>> don't > >>> think more than that. Now to the table. The height of the Joe Norton > >>> tree reflects Andrew's tape drop measurement. > >>> > >>> > >>> Crown Distance - Yds Crown Angle -degrees Hgt Above Eye Level > >>> -ft > >>> Base Distance - Yds Base Angle -degrees Hgt Below Eye Level - > >>> ft > >>> Offset -ft Total Tree Height-ft Tree Name Tag # Date > >>> 72.00 31.50 112.86 62.00 17.20 55.00 1.50 > >>> 169.36 Jake > >>> Swamp 58 12/2/09 > >>> 163.50 163.50 Joe > >>> Norton 52 10/17/09 > >>> 61.00 49.00 138.11 37.00 11.80 22.70 > >>> 160.81 John Brown 48 > >>> 12/2/09 > >>> 63.00 37.60 115.32 52.00 13.00 35.09 6.70 > >>> 157.11 Tom > >>> Porter 31 12/2/09 > >>> 55.00 48.00 122.62 42.00 15.50 33.67 > >>> 156.29 Tuning Fork > >>> 44 12/2/09 > >>> 68.50 37.90 126.24 55.00 10.20 29.22 0.60 > >>> 156.05 Mirror 77 > >>> 12/7/09 > >>> 59.00 37.90 108.73 47.50 18.60 45.45 1.10 > >>> 155.28 Arovl Lookin > >>> Horse 26 12/2/09 > >>> 60.50 50.50 140.05 41.00 4.90 10.51 4.50 > >>> 155.06 Unnamed 37 > >>> 12/2/09 > >>> 66.00 41.40 130.94 52.50 6.80 18.65 5.00 > >>> 154.59 Lynn > >>> Rogers 34 12/2/09 > >>> 51.50 54.90 126.40 28.00 18.50 26.65 1.30 > >>> 154.36 Paula > >>> Horn 27 11/4/09 > >>> 53.00 50.80 123.22 39.00 15.00 30.28 > >>> 153.50 Tribe-1 41 > >>> 12/2/09 > >>> 64.00 36.80 115.01 53.50 13.70 38.01 > >>> 153.03 Ravine 82 12/7/09 > >>> 57.50 49.20 130.58 36.00 7.70 14.47 6.00 > >>> 151.05 Guardian 70 > >>> 12/2/09 > >>> 55.50 52.60 132.27 41.00 8.60 18.39 > >>> 150.66 Unnamed 35 12/2/09 > >>> 53.00 49.00 120.00 36.00 13.70 25.58 5.00 > >>> 150.58 Hollow 83 > >>> 12/7/09 > >>> 55.50 47.20 122.17 37.00 14.50 27.79 0.50 > >>> 150.46 Ann Joc > >>> None 12/2/09 > >>> 63.00 44.80 133.18 44.00 7.50 17.23 > >>> 150.41 Unnamed 85 12/2/09 > >>> 49.00 60.90 128.44 24.00 12.30 15.34 6.60 > >>> 150.38 Unnamed 28 > >>> 12/7/09 > >>> 67.00 32.10 106.81 57.00 14.70 43.39 > >>> 150.20 Unnamed 5 12/2/09 > >>> 63.00 38.60 117.91 57.00 9.00 26.75 4.80 > >>> 149.46 Unnamed 36 > >>> 12/2/09 > >>> 51.00 52.80 121.87 32.50 12.20 20.60 5.60 > >>> 148.07 Member of > >>> Tribe 40 12/7/09 > >>> 63.00 39.70 120.73 51.50 7.70 20.70 5.00 > >>> 146.43 Dave Chief > >>> 63 12/7/09 > >>> 47.00 54.00 114.07 29.00 16.60 24.85 6.50 > >>> 145.43 Road > >>> warrior 79 12/7/09 > >>> 53.50 42.60 108.64 39.50 18.00 36.62 > >>> 145.26 Dave Chief 63 > >>> 12/2/09 > >>> 53.00 43.90 110.25 40.50 13.30 27.95 6.30 > >>> 144.50 Italian > >>> None 12/2/09 > >>> 48.00 51.20 112.22 34.00 11.20 19.81 6.00 > >>> 138.04 Member of > >>> Tribe 39 12/7/09 > >>> 47.50 50.40 109.80 31.50 10.90 17.87 6.30 > >>> 133.97 Unnamed 29 > >>> 12/7/09 > >>> > >>> > >>> Before I left, I measured one tree in the Cherokee-Choctaw area. It > >>> is > >>> a tree visible from the the road down to the lower meadow. I spent a > >>> good 35 minutes with the tree and finally settled on a height of > >>> 149.3 > >>> feet. The pine's girth is 10.1 feet in girth. This is the second > >>> pine > >>> I've confirmed in the re-measurement project above 149 feet but not > >>> quite 150. Next year, both should be inducted into the 150 Club. > >>> > >>> So what's the bottom line? The final count of 150s in the Trees of > >>> Peace stands at 19. The net change of 150s is down by one from > >>> what I > >>> previously had listed. The Dave Chief was a big surprise. I > >>> re-measured it again and can't get over 146.4 feet. It used to be a > >>> 150. Gain some, lose some. > >>> > >>> Bob > >>> -- > >>> Eastern Native Tree Society http://www.nativetreesociety.org > >>> Send email to [email protected] > >>> Visit this group at http://groups.google.com/group/entstrees?hl=en > >>> To unsubscribe send email to [email protected] > >> > >> -- > >> Eastern Native Tree Society http://www.nativetreesociety.org > >> Send email to [email protected] > >> Visit this group at http://groups.google.com/group/entstrees?hl=en > >> To unsubscribe send email to [email protected] > > > > -- > > Eastern Native Tree Society http://www.nativetreesociety.org > > Send email to [email protected] > > Visit this group at http://groups.google.com/group/entstrees?hl=en > > To unsubscribe send email to [email protected] > > -- > Eastern Native Tree Society http://www.nativetreesociety.org > Send email to [email protected] > Visit this group at http://groups.google.com/group/entstrees?hl=en > To unsubscribe send email to [email protected] _________________________________________________________________ Get gifts for them and cashback for you. Try Bing now. http://www.bing.com/shopping/search?q=xbox+games&scope=cashback&form=MSHYCB&publ=WLHMTAG&crea=TEXT_MSHYCB_Shopping_Giftsforthem_cashback_1x1 -- Eastern Native Tree Society http://www.nativetreesociety.org Send email to [email protected] Visit this group at http://groups.google.com/group/entstrees?hl=en To unsubscribe send email to [email protected]
