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Norman Oklahoma
(@norman-oklahoma)
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December 4, 2018 3:45 pm  

What proportion of your surveys are on a local coordinate system?   

"Convention is like the shell to the chick, a protection till he is strong enough to break it through." Learned Hand


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JKinAK
(@jkinak)
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December 4, 2018 4:09 pm  

If you mean local arbitrary system not tied to WGS84: less than 2%

If you mean local low distortion projection that is geodetically referenced: greater than 98%

If you mean both: 100%

- John


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John Putnam
(@john-putnam)
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December 4, 2018 4:27 pm  

Off the top of my head I can't think of the last time I set up a project on random / local coordinate system.  I have been brought in to work on projects that appear to be local (without proper meta data it is hard to say).  Just this morning, the practice of tying into an established system paid off big time.  At the end of October I did a little design survey for about 600 feet of track realignment in a mill.  The engineer was supposed to design it the next day so I could turn around and lay it out.  I set two control points and tied them to the ORGN.  The plans were not completed until yesterday.  I went today to find that one of my two points had been the victim of a utility relocation crew at the end of last week.  Being able to set a new point saved my bacon.

John Putnam, PLS
OR, CA, WA & ID


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Norman Oklahoma
(@norman-oklahoma)
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December 4, 2018 4:36 pm  

By local coordinate system I mean 5000/5000 (or similar) with bearings based on some classical method such as an old survey line, compass, sunshot,  or just assumed. Not geodetically referenced.

For the record I would wager that well over 90% of surveys done in the Portland/Vancouver area are on local systems.   

This post was modified 2 weeks ago 2 times by Norman Oklahoma

"Convention is like the shell to the chick, a protection till he is strong enough to break it through." Learned Hand


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Williwaw
(@williwaw)
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December 4, 2018 5:01 pm  

Maybe 5% of the jobs I do are done on local systems. They tend to be small  and simple jobs done using conventional equipment where the scope is very limited, or they're based on legacy work that was done on such a system where it's just easier and less hassle to stay within the confines of what had been done previously. These days 95% of my work is done in State Plane and tied to the CORS network. I'm just finishing up a project utilizing ties from four previous surveys done over the last decade. Likely saved me several days of work and my client never argues when I save them money by recycling data they've already paid for once. 

This post was modified 2 weeks ago by Williwaw

Just because I'm paranoid doesn't mean they're not out to get me.


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linebender
(@linebender)
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December 4, 2018 5:18 pm  

Zero % for more than 20 years


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Precision Geosystems, Where Precision Meets Value.

Loyal
(@loyal)
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December 4, 2018 5:20 pm  

ZERO% in the last [nearly] 40 years. Ye ol' 5k5k w/a solar was SOP back in the 60s & 70s, but by the mid-70s MOST of my work was tied into the National Network via USC&GS Triangulation Stations.

Loyal 

"Perilous to us all are the devices of an art deeper than we possess ourselves."
Gandalf, The Two Towers


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Norman Oklahoma
(@norman-oklahoma)
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December 4, 2018 5:41 pm  

I'm seeing a trend here .... I know that somebody out there is doing 5000/5000 surveys .... don't be shy. Seattle? Vancouver, B.C.? Or is Portland  the last bastion of non-geodetically referenced surveys?

"Convention is like the shell to the chick, a protection till he is strong enough to break it through." Learned Hand


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roger_LS
(@roger_ls)
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Posts: 441
December 4, 2018 5:58 pm  

99.5% on local coordinate system. 5000, 5000

Reviewing boundary surveys becomes so much more confused and tedious when a survey is not using bearings from an original subdivision map or local deeds or mapping. It's a real pain to make sense of how they've done what they've done. You have to be constantly comparing the difference between measured bearing shown and the original record. Boundary surveying is already complicated enough, why add another level of complexity. Global coordinate systems are overrated and unnecessarily used too much of the time. Keep it local! 

This post was modified 2 weeks ago by roger_LS

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Jim Frame
(@jim-frame)
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December 4, 2018 6:11 pm  

For urban surveys I generally start and stay local (though I prefer 15000,15000 to 5000,5000).  For rural surveys (which tend to be referenced to the PLSS) I'll start with SPC and finish the mapping local/ground (Star*Net makes this very easy to do).  The local university campus is on a nominal NAD83/NAVD88 system, but it's an older epoch and height realization, so it's usually best to reference the campus monuments; that makes it more of a local system.  For urban corridor surveys of any significant length (i.e. over 1/4 mile or so) I'll usually use SPC/NAVD88.

It depends.  🙂

Jim Frame
Frame Surveying & Mapping
609 A Street
Davis, CA 95616


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hlbennettpls
(@hlbennettpls)
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Posts: 318
December 4, 2018 6:15 pm  

I'd be willing to guess 99% of mine are.  It was a trend years ago when the company started to do sectional worksheets since most of the stuff around here was acreage and we've kept the trend alive.  I've thought about translating and rotating, but I have some of these worksheets with well over 1,000 jobs in them and it would mean every time we went back to that job and did something that needed to be added to that survey it would need to be translated and rotated.  I just can't see the need to do it.  If I have a project in one that needs to be in real world coordinates I simply translate and rotate that 1 job instead of many.  Any new worksheets we do are in real word coordinates though as I see the benefit of having them as such.


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JPH
 JPH
(@jph)
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Posts: 987
December 4, 2018 6:50 pm  

Half.  Boundary surveys are mostly local, don't see much of a reason to put them on SPC.  ROW surveys are obviously SPC.


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holy cow
(@holy-cow)
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December 4, 2018 6:51 pm  

Any job that can be done without GPS will be local coordinates.  That is a substantial percentage.


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MightyMoe
(@mightymoe)
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December 5, 2018 6:52 am  

Every survey is tied to Geodetic Coordinates (NAD83 various epochs). The XY coordinates don't mean much to me. With a very few exceptions none are on State Plane but can be converted very easily in the rare case where someone wants some State Plane coordinates.  

And that's basically been the same since the late 70's, back then lot surveys were maybe 1/2 done on a 10000, 10000 assumed bearing system and the other 1/2 tied into a control network, but even then all large surveys were tied to NAD27 monuments and bench marks.

Using Geodetic Coordinates doesn't mean that you can't use local bearings, that is easily done with an LDP, or a simple rotation that most programs allow, might as well, you get the best of both worlds. 

 


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James Fleming
(@james-fleming)
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December 5, 2018 7:10 am  

Surveys for civil design; 100%

Retracement surveys 80%

Monitoring 0%

We have a lot of GIS resources available to download and pretty robust RTN network(s).  It makes sense to put all but the smallest urban boundaries in SPC to be able to bring in photos, aerial topo, etc.

“Civilization is not an endless succession of inventions and discoveries, but the task of ensuring that certain things last.”
— Nicolás Gómez Dávila


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