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Permalink Reply by J. Anthony Cavell on June 10, 2018 at 1:20pm

-The first possibility is that a point was disturbed.

-Secondly, check your data to be sure scale factors, projections, and datums are EXACTLY the same.

- Check the specs on your prisms and which ones were placed where.

- Of course, consider operator error, poor instrument or reflector setup.

The solution is not obvious given the limited data. 
The old carpenter's saying, "measure twice; cut once" can be very important in surveying as well. Make sure two sets of observations agree before acting on them. If they don't agree, take another set of observations.

Good luck,

JAC

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Permalink Reply by Mohammad Salem on June 10, 2018 at 11:51pm

Thanks  J. Anthony Cavell 

as you said  measurements, so we have measured twice the control points but in both we faced mass mach location of objects were in the first location that were surveyed first. 

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Permalink Reply by J. Anthony Cavell on June 11, 2018 at 8:38am

Mr. Salem,

I'm sorry; I don't understand your meaning. Please explain to me again.

JAC

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Permalink Reply by Mohammad Salem on June 11, 2018 at 11:42pm

Dear J. Anthony Cavell 

I said we have measured survey control points ones again in the site and in the second round as well we faced this problem, relocation of objects than the first round, during measurement the accuracy in each station setup was 1-4 mm you think of about 18 station setups were made, now in the result it shows 20-60 cm relocation in objects and control points than the first step surveying!!! 

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Permalink Reply by J. Anthony Cavell on June 12, 2018 at 8:13am

Dear Mr. Salem,

Are you surveying radially from a single point, shooting other points from one setup?

Are you surveying radially from a few points, shooting other points from only a few setups?

Or are you running a traverse through the points, closing back on the beginning?

JAC

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Permalink Reply by Mohammad Salem on June 12, 2018 at 11:47pm

Dear  J. Anthony Cavell

We have installed few points trough out the site, shooting other points around from mentioned installed points. 

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Permalink Reply by J. Anthony Cavell on June 13, 2018 at 12:53am

I'm sorry I cannot offer an solution. I cannot find a cause for your problem. I probably would have to witness the situation personally to find the cause.

JAC

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