Survey Control

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pls5528
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Joined: Sat Jan 27, 2007 5:42 pm

Survey Control

Postby pls5528 » Wed Jun 05, 2019 3:35 pm

I have always known that your "survey control" is essential for a successful project. Planning for how to establish such control should be a prerequisite of each project, and, what accuracy you wish to achieve. If you were performing a large project which requires ties to Caltran's or NGS based monuments, an ALTA survey or a small boundary/topo survey in a rural countryside, your planning for how to approach the job and what control to initially use is a critical and essential path to success. I personally like "checklists". If checklists are used, they should be developed beforehand and suitable for the current standards specific to your project. I personally have developed some of these checklists and have broken them out for both "Field" and "Office", which has proven to me to be effective.
Survey control performed in the field should to be analyzed and/or directed by an LS (which is competent in performing such work). Note, that I added "competence in performing such work" in the last sentence. As with civil engineering, land surveyors in the industry have strengths and weaknesses in their respective knowledge and training, and should not attempt to do such work, unless it is being directed under an LS that is competent in such work. The final evaluation and analysis of such control, should be documented (both horizontal and vertical control) and saved. If one was ever needed to provide proof of such survey control accuracies, by a client, city, county or, in court, you should be able to provide such documentation with confidence.
I have personally had discussions with some in our industry about the issue of "control", only to hear, "It's Close Enough"! Some simply float a geometric puzzle of land around until it fits close to the monuments. That reminds me when Dorothy's house fell down from the tornado in the Wizard of OZ movie? Where it falls, is where it is. Professionally, I beg to differ! There is NO way to validate such control, nor is it following any kind of legal principles which relate thereof. My thought is that we are hired to be professionals, and as such, perform our duties accordingly. As Joe Friday said, just present the facts Ma'am!
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Jim Frame
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Re: Survey Control

Postby Jim Frame » Fri Jun 07, 2019 9:32 pm

I think that most surveyors who've been around awhile carry those checklists in their head, and modify them according to the project at hand. It's a rare job for which I'll actually run a Star*Met preanalysis to make sure my control plan meets specs (though I did run one just last week). I mostly plan the control as I go, and it's not often that I'm unpleasantly surprised by the results.
Jim Frame
Frame Surveying & Mapping
609 A Street
Davis, CA 95616
[url]framesurveying.com[/url]

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pls5528
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Re: Survey Control

Postby pls5528 » Sat Jun 08, 2019 8:17 am

You are right Jim, in "that most surveyor's who have been around awhile carry those checklists in their head". In that I have managed crews, and office staff for the best part of 25-years, I found that these checklists (for the ones which perhaps have not been around for awhile) are both educational to them and provide accountability to those staff working under my direction. In the previous years in the field, I many times would perform traverse closures, adjustments, and final analysis in the field, document all in my field book-----DONE.
You mentioned "Star Net", which was one of my favorite programs I used in the past. The original support guys were always great!.

A.Westerlund
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Joined: Thu May 14, 2015 1:09 pm

Re: Survey Control

Postby A.Westerlund » Sat Jun 08, 2019 1:42 pm

Are you willing to elaborate on some of those checklist items?

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mpallamary
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Re: Survey Control

Postby mpallamary » Sat Jun 08, 2019 2:48 pm

The lost art of land surveying and understanding strength of figures.

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land butcher
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Location: calif

Re: Survey Control

Postby land butcher » Mon Jun 10, 2019 5:55 pm

I did a lot of ALTAs and other projects for many companies, on my first visit to any job I drive it so I know what I am dealing with. This is especially needed with aerials and the placement of targets. I had one office LS ask, when I called in about 10am to tell him the targets were set, asked me why I didn't set them first thing. He had no clue as to the number of times I was sent out to control targets set by someone else that could have been set in a near but different location and would not have required a special CP just to tie in that target. Same office LS that always said "Work smarter not harder".

Another thing is on a large control net is to make cross ties. I set the mons on one site near a dam but they had their super chief with the 1 second gun run the control on them. He made no cross ties and not long after the coordinates were distributed to others I was sent out there and for giggles made a cross tie, ~3 tenths in less than 1000 ft. The lines he ran were good but the net had a bow in it.

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pls5528
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Re: Survey Control

Postby pls5528 » Tue Jun 11, 2019 3:35 pm

A.Westerlund wrote:Are you willing to elaborate on some of those checklist items?


What are you looking for? I am glad to share some of what I have. Email me at pls5528@gmail.com

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pls5528
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Re: Survey Control

Postby pls5528 » Thu Jun 13, 2019 3:09 pm

mpallamary wrote:The lost art of land surveying and understanding strength of figures.


Ahhh yes. If it didn't fit within the acceptable table values, plan it out again. Before GPS, I remember doing Triangulation and Trilateration on large areas in the low deserts of California. Sometimes we would do it at night using the headlight of the truck to get out angles. Other times, the old Rangermaster. Fun days


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