@olemanriver?ÿ ?ÿ0848 but sometime just before I got out in Feb. 1970, they changed it to 0844.?ÿ My second MOS was 5711
@john-nolton oh i don??t. Yes he could shuck the corn clean down to the cob (southern for story teller). He sure could. When they would all come out to Corbin for camp fires and drinks. He was always in the middle of a great story.?ÿ
@john-nolton Artillery. ?ÿI was an 0261. I can??t remember but they combined the geodetic surveying and Cartography/gis prior to me coming in i think the geodetic surveying was a 14xx number. Then we also had the artillery surveyors. But all those good ole days are behind me now. ?ÿNow I look forward to following old surveys deeds plats etc. just have not found the right company yet so i can do more of them. Lots of companies staking curb n gutter etc. ?ÿtopos. Well Semper Fi. If you ever out this way give a shout. I will buy the first round.?ÿ
It??s interesting that there??s calibration baselines for checking total station distances, while many surveyors rely heavily on RTK (VRS/RTN even which has more error than local base RTK), where with RTK you can measure two points , then measure those points an hour later and observe a different distance between them compared to the first observation. Basically RTK (VRS is network RTK and has more error than local base RTK) is a variable distance measuring device. ????
Oh my. "...more error..." This has been discussed often here, probably more like beat to death.?ÿ
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Is a calibrated steel tape more precise over short distances than an EDM? Could be.
Is an EDM more precise over certain distances than a steel tape? Could be.
Are GNSS observations more precise than EDM or steel tapes at some distances (between points). Could be.
Are any of those tools more accurate than any other tool you might use? Depends.?ÿ
No, RTK/VRS/RTN/Static, etc does not have "more error" than whatever. No, VRS or Network RTK does not necessarily have "more error" than a standalone base.?ÿ?ÿ
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Is a calibrated steel tape more precise over short distances than an EDM? Could be.
Is an EDM more precise over certain distances than a steel tape? Could be.
Are GNSS observations more precise than EDM or steel tapes at some distances (between points). Could be.
Are any of those tools more accurate than any other tool you might use? Depends.?ÿ
No, RTK/VRS/RTN/Static, etc does not have "more error" than whatever. No, VRS or Network RTK does not necessarily have "more error" than a standalone base.?ÿ?ÿ
Hear, hear. I've worked with some folks that really should have the entirety of this post tattooed on their forehead.
I took my javad to the baseline.?ÿ
Now they know brg and distances between them.
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Just kidding!!
Nate
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Is a calibrated steel tape more precise over short distances than an EDM? Could be.
The precisions of those measurements do not change with distance. The relative accuracy does.
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Is a calibrated steel tape more precise over short distances than an EDM? Could be.
A test I took indicated that it indeed is.
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Is a calibrated steel tape more precise over short distances than an EDM? Could be.
The precisions of those measurements do not change with distance. The relative accuracy does.
I said "could be" but still let's explore this, not because @bill93 doesn't know, but because it might be useful for @robertusa
(Honestly, I know I could learn a lot about many things, including measurements, from Bill, as he is a polymath and I am barely a one trick pony.)
For a chain, the theoretical precision may not change, but in practice it does. Perhaps we would then say it is accuracy, but for a 1,000 meter measurement I will argue that an EDM is more precise than using a chain. It MAY also be more accurate, if said EDM is correctly calibrated.
In practice, breaking chain will provide a less precise measurement than an EDM right off the bat (especially for any crew member born after 1980).?ÿ
And of course the way we define an EDM's precision means that it changes over distance. The specs call out: 2mm+1.5 PPM. You start out with 2mm+/- (meaning that if you made many measurements you could expect them all to fall within 2mm of the mean with an overall spread of 4mm from highest to lowest. And, that 2mm is 100% there for any measurement that EDM makes. 2mm from the mean is more relevant to precision at 1 meter than at 1000 meters.
Also, in practice, having to traverse and introducing all those additional setup and sighting errors will reduce the precision of the measurement, much as breaking chain reduces precision.
But perhaps I was imprecise in my choice of words. I will add some clarification: (I wish I had said as to avoid confusion.)
Within the working limits of a single measurement (without breaking chain), the tape will typically exceed the precision of the EDM. Within the working limits of a single set up, an EDM will typically exceed the precision of RTK. That is not "more error". In fact, as we increase the distances between the points we measure, we often find that the tape or an EDM are tools that do not allow measurements as precise or as accurate as those that are possible with RTK/VRS.
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And again, Bill, I do not suppose to teach you this, but perhaps further the discussion and more correctly state what I meant.
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Is a calibrated steel tape more precise over short distances than an EDM? Could be.
A test I took indicated that it indeed is.
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I answered that question as well...but they never tell you which ones you answered incorrectly.
@jitterboogie?ÿ Taking it to the extreme often provides the answer. If you are measuring between two points about a half-inch apart I'll take a pocket tape or scale any day. If you are measuring across the Grand Canyon it will be RTK hands down.
I contacted the NGS I&M Branch about the 100 foot monument and was told they were no longer supported due to a lack of interest by surveyors.
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This is all great, and we should be concerned enough to make sure that our equipment is well tuned and working properly.?ÿ But I don't think our measurements and/or techniques are what might get us into real trouble
Hi Everyone, don't forget that if you have relevant info to share about an NGS CBL that may help others recover it or be better prepared to use it, or not use it... please let us know.
Contact the CBL Program team via: ngs.cbl@noaa.gov
Or reach out to the Regional Geodetic Advisor via phone or email and he or she can ensure your information gets delivered to the CBL team: https://geodesy.noaa.gov/ADVISORS/
We are rarely able to do preventative site visits, so any information on access, vegetative growth, safety precautions, etc., could help the next person know what they'd be up against.?ÿ There's some nice CBLs out there, but there's also a lot that are nearly unusable or downright unusable.
Oh, and @RobertUSA myself and at least one other advisor have been mumbling internally that we ought to provide a "GNSS CBL" of sorts, that would allow users to validate their entire system: from antenna to post-processing to coordinate conversions.?ÿ ?ÿIt's mostly just a thought experiment at this point, but some personnel have at least agreed it would be a valuable service, and could potentially be a part of some future version of OPUS.
