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The 0.04' Is Currently On The West Coast

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(@jim-frame)
Posts: 7277
Topic starter
 

A 1973 Record of Survey shows 3/4" iron pipes set at each end of a 1205.56' line. I found both pipes in good condition today and measured 1205.60' between them. I missed his 1973 bearing by 4 seconds; I'm on CCS83, he was on a Caltrans realization of NAD27.

He sure made my job easy!

 
Posted : April 30, 2014 9:13 pm
(@rankin_file)
Posts: 4016
 

[sarcasm]So... have you figured out which one is off? But then, maybe they're both off !?!?!!? [/sarcasm] o.O

 
Posted : April 30, 2014 9:29 pm
(@deleted-user)
Posts: 8349
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"He sure made my job easy!"

Boy Howdy to that, all you had to do is yank his out and put yours in! 😉

 
Posted : May 1, 2014 3:26 am
(@dave-ingram)
Posts: 2142
 

Seismic activity.

 
Posted : May 1, 2014 3:38 am
(@holy-cow)
Posts: 25292
 

Go out tomorrow and shoot those two points again. Then report on the difference found.

 
Posted : May 1, 2014 4:39 am
(@oxnard-kurt)
Posts: 11
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I am more surprised by the Bearing being so close. I have rarely found NAD27 Bearings matching NAD83 Bearings. I suspect that all the systematic errors fell in your favor this time.

 
Posted : May 1, 2014 4:51 am
(@jim-frame)
Posts: 7277
Topic starter
 

> I am more surprised by the Bearing being so close. I have rarely found NAD27 Bearings matching NAD83 Bearings.

It's actually pretty common around here when following up on 1960's-era Caltrans work. I've never investigated to see if the orientation of NAD27 and NAD83 are aligned in this region, or if there was something peculiar about the way Caltrans realized NAD27, but I know other surveyors who have noticed the same coincidence.

 
Posted : May 1, 2014 5:23 am
(@jered-mcgrath-pls)
Posts: 1376
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> A 1973 Record of Survey shows 3/4" iron pipes set at each end of a 1205.56' line. I found both pipes in good condition today and measured 1205.60' between them. I missed his 1973 bearing by 4 seconds; I'm on CCS83, he was on a Caltrans realization of NAD27.
>
> He sure made my job easy!

[sarcasm]Probably should epoxy an aluminum cap to those pipes so you can properly punch the distance.[/sarcasm];-)

 
Posted : May 1, 2014 6:29 am
(@ric-moore)
Posts: 842
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I think filing a complaint is in order

 
Posted : May 1, 2014 7:01 am
(@mapman)
Posts: 651
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Often the bearing difference is surprisingly small in the southern region too. Would be interesting to see how the variances would stack up throughout the state. Probably due to the Lambert system and multiple zones.

 
Posted : May 1, 2014 8:21 am