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Fixing a classic blunder  

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Posts: 3
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(@carrolltown)
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Joined: 2 months ago

I made a classic blunder while surveying last week with a Sokkia total station.

I had 3 known points on site. A, B and C.

In the controller I had set the occupy point as B and the back sight as C. In reality I was occupying A and B was my back sight.

This has caused the coordinate calculations in the controller to be incorrect. So I'll need to recalculate those coordinates. In short, the controller believes that the measured back sight relationship is between points B and C, when the measured angles are actually between A and B.

I have access to the raw file (.rw5) but am having trouble understanding what changes I need to make to get the proper coordinate calculations. Ideally I can make a change in the controller and not recalculate using the raw file. The controller is a Carlson controller running SurvCE.

 

Any help is much appreciated. If there are any additional data are needed to crack this thing, let me know.

 

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Stephen Ward
Posts: 1960
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(@stephen-ward)
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Joined: 8 years ago

If you know the range of points collected from the bad setup, you can fix it with a simple translate/rotate.  CREATE A COPY OF THE FILE BEFORE YOU DO ANYTHING ELSE.  Translate the group of points from B to A, then rotate the group of points around A using B-C as the original azimuth and A-B as the new azimuth.

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Posts: 3
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(@carrolltown)
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Joined: 2 months ago

Thanks for the response.

I've made back-ups of this dataset from 9 ways from Sunday - so no worries there.

The translate and rotate method makes sense for getting the points in the correct (x,y) space. But what about transforming the data in the z direction (elevation)?

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Stephen Ward
Posts: 1960
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(@stephen-ward)
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Joined: 8 years ago

Assuming that your HI was correct, a 3d translate from B to A in step one above should fix the horizontal and vertical.

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kjypls
Posts: 180
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(@kjypls)
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Joined: 4 years ago

Editing the .rw5 on the collector is tedious, but pretty easy.

After you edit it, you can save it as a different file name. Then, you need to process it (your re-named .rw5) and give it the OK to overwrite the points in .crd

 

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