Laser Targets: Important?

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Re: Laser Targets: Important?

Postby GroundquestMSA » Nov 5, 2013 7:00 am

Of course, there are no fractions uttered in the cave (except when Laser Boy wants to goof off). I've been measuring to the nearest inch. Since I'm a member of the low-class, construction trade caste, my brain is already programmed to process standard units.
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Re: Laser Targets: Important?

Postby JSDunham » Nov 5, 2013 7:05 am

Extremeophile wrote:I've had difficulty getting readings when the shot is long and there's a lot of mist, but I haven't had issues with false readings. With the Leica distos you generally get the "255" error when the laser reflects off multiple surfaces (e.g. partly glancing off an intermediate wall, or a dome full of water droplets).


Yes--when I say problems with the readings, I mean problems getting them, not problems with their accuracy. I have only had accuracy problems with wet angled surfaces (and I note that GroundquestMSA's angled test readings were the most variable in that regard).
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Re: Laser Targets: Important?

Postby Extremeophile » Nov 5, 2013 11:08 am

GroundquestMSA wrote:Of course, there are no fractions uttered in the cave (except when Laser Boy wants to goof off). I've been measuring to the nearest inch. Since I'm a member of the low-class, construction trade caste, my brain is already programmed to process standard units.

If you go to an engineering scale, even if you stay with feet, i.e. feet, tenths of feet, hundredths of feet, you will find it much easier to enter the data into a computer, and it will reduce confusion if others ever need to refer to your notes. The last time anyone used inches in a survey was 1972.
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Re: Laser Targets: Important?

Postby GroundquestMSA » Nov 5, 2013 4:19 pm

Extremeophile wrote:If you go to an engineering scale, even if you stay with feet, i.e. feet, tenths of feet, hundredths of feet, you will find it much easier to enter the data into a computer, and it will reduce confusion if others ever need to refer to your notes.


Though I've never entered survey data into a computer and while no one will ever refer to my survey notes (at least the ones produced so far), I get your point.

Extremeophile wrote:The last time anyone used inches in a survey was 1972.

:laughing: No, it was Saturday. Which was also the last time anyone surveyed a 16' "cave." Sunday, I guess, was the last time anyone drew a map by hand. I belong in 1972, I really do.
Last edited by GroundquestMSA on Nov 6, 2013 6:43 am, edited 1 time in total.
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Re: Laser Targets: Important?

Postby NZcaver » Nov 5, 2013 6:42 pm

Or better still... go metric. :tonguecheek:
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Re: Laser Targets: Important?

Postby GroundquestMSA » Nov 5, 2013 8:03 pm

Using the engineers scale of my fiberglass tape would also waste the clever phrase coined to keep us on the standard scale, "The white side is the right side."
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Re: Laser Targets: Important?

Postby NZcaver » Nov 6, 2013 12:05 am

Wait a minute... fiberglass tape? Is that what you use for a lanyard on your laser? :big grin:
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Re: Laser Targets: Important?

Postby Bob Thrun » Nov 6, 2013 12:31 pm

Extremeophile wrote:[
If you go to an engineering scale, even if you stay with feet, i.e. feet, tenths of feet, hundredths of feet, you will find it much easier to enter the data into a computer,

I am puzzled by the claim that feet and decimals are easier to enter into a computer than feet and inches. I have heard this claim several times and I do not understand it. It takes exactly the same amount of typing for "12 6" as it does for "12.5".

I record data using whatever is the smallest numbered unit of the tape: tenths of feet, inches, or centimeters. Recording anything smaller does not add to accuracy because errors in the angle measurements dominate the overall error. A survey would be almost as accurate if distances were measured to 3 to 4 inches, or 75 to 100 millimeters. My Disto reads to a hundredth of a foot. I use the distances with the hundredths because it is easier and less error prone to write them that way than it would be rounding the numbers in the cave.

I do not like survey programs that keep data files in one unit. For instance 14 5 feet is stored as 14.42 and 4.15 meters is stored as 13.62. I like to keep data in the original units
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Re: Laser Targets: Important?

Postby Extremeophile » Nov 6, 2013 6:28 pm

Bob Thrun wrote:
Extremeophile wrote:If you go to an engineering scale, even if you stay with feet, i.e. feet, tenths of feet, hundredths of feet, you will find it much easier to enter the data into a computer,

I am puzzled by the claim that feet and decimals are easier to enter into a computer than feet and inches. I have heard this claim several times and I do not understand it. It takes exactly the same amount of typing for "12 6" as it does for "12.5"

Maybe there's a shortcut I'm not aware of ... are you saying that when you leave a space between numbers that all the various software programs recognize this as feet and inches? All this time I've been converting inches and fractions of inches into decimals before entering the data. It's one of the reasons, where I work, that we use rulers with tenths of inches rather than 1/2, 1/4, 1/8 etc.

Another advantage of an engineering scale is not needing to qualify the reading you're giving with a unit, e.g. "twenty four point five" rather than "twenty four feet, six inches".

A problem with converting inches to decimal feet is you end up with data that doesn't represent the true precision of the reading.
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Re: Laser Targets: Important?

Postby Bob Thrun » Nov 7, 2013 2:22 pm

Extremeophile wrote:[
Maybe there's a shortcut I'm not aware of ... are you saying that when you leave a space between numbers that all the various software programs recognize this as feet and inches? All this time I've been converting inches and fractions of inches into decimals before entering the data. It's one of the reasons, where I work, that we use rulers with tenths of inches rather than 1/2, 1/4, 1/8 etc..

I was thinking mainly of my software. I believe in letting the computer do the conversion sork. I looked at the Compass Help file. It looks like Compass might have a similar feature. Maybe someone else could say for sure.
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Re: Laser Targets: Important?

Postby lleblanc » Nov 8, 2013 10:27 am

Extremeophile wrote:Maybe there's a shortcut I'm not aware of ... are you saying that when you leave a space between numbers that all the various software programs recognize this as feet and inches?etc.


While I still handle lumber in feet-inches and fractions, I survey in meters unless feet are required.

Nonetheless, Auriga supports feet-inches. They get displayed with ' and " but for convenience, they can be entered with just a separating space. Internally, they get converted to decimal feet with 2 decimals. This is the only time Auriga performs a conversion. Other than that, numeric data is kept unit-less and the session (aka survey in Compass) determines the unit. Raw data remains as input, but conversions may be necessary during computations when various units are mixed within a given cave.

Extremeophile wrote:Another advantage of an engineering scale is not needing to qualify the reading you're giving with a unit, e.g. "twenty four point five" rather than "twenty four feet, six inches".


But you could say "twenty four feet, six" and that would be as clear. Or "twenty four space, six" since this is the way it would get input. My preference would go to "two four space six".
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