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Important Signficant Figures Question

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(@imaudigger)
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Yes, I agree

 
Posted : 13/02/2014 9:25 pm
(@steve-d)
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In my mind the question of what I report relates to what measurements I can repeat with a high degree of confidence. I would not want to report an area or spot as out of speck if I could not reproduce the measurement within the significant figures of my equipment and methodology. Application of professional judgment is always a part of the “art” of surveying. In short I agree with others, I think you report what you find; however be certain your number is accurate, not just precise.

 
Posted : 14/02/2014 4:09 am
(@duane-frymire)
Posts: 1924
 

The engineering textbook I use states fractions must be converted to thousandths in decimal form. So the conversion is you need to be within 0.021 feet. Outside of that is outside of spec.. So, you need to be using equipment and procedures that measure to the nearest thousandths of a foot, repeatable at whatever precision is in the spec.. Is a confidence level specified, such as sd or 95%, etc..

Oh, I see they specified the test, nevermind.

 
Posted : 14/02/2014 6:10 am
(@glenn-breysacher)
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> The engineering textbook I use states fractions must be converted to thousandths in decimal form. So the conversion is you need to be within 0.021 feet. Outside of that is outside of spec.. So, you need to be using equipment and procedures that measure to the nearest thousandths of a foot, repeatable at whatever precision is in the spec.. Is a confidence level specified, such as sd or 95%, etc..
>
> Oh, I see they specified the test, nevermind.

Just what Duane said. Take the conservative view that anything beyond the decimal equivalent is exceeding the spec. Common sense dictates otherwise, as Kent said, if you try to fix something that isn't broke, you might break it.

 
Posted : 14/02/2014 6:49 am
 vern
(@vern)
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What is that pavement for? Those are some really tight specs for asphalt. 5/8" was the limit on the airport taxiways we paved last fall but the smoothness straight edge was 16 feet. There were also allowances for a certain percentage to be out but not exceed a certain amount.

We have some really good asphalt crews and state of the art equipment but I'm not sure we could meet that spec. [sarcasm]Was it staked for paving on a ten foot grid? [/sarcasm]

 
Posted : 14/02/2014 10:30 pm
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