double correction for curvature and refraction...how to fix?

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double correction for curvature and refraction...how to fix?

Postby mlbrack » Mon Mar 03, 2008 7:25 am

I rented a total station a while back to complete a project. I was assurred that it was not correcting for curvature and refraction, and I used FG for make the correction.

When adjusting optical work to a gps control net, I found that the gun had been correcting for curvature and refraction. So now, my elevations are corrected twice for curvature and refraction, once by the gun and once by FG.

Anyone have an idea of an easy was to fix this, or do I need to go through the project and manually adjust each elevations shot by shot?
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Postby Jason Poitras » Thu Mar 13, 2008 12:16 pm

Hi Mike,

I believe you already got an answer to your question via our support department.

I thought I would write a quick note about this so other users can learn from your question. Curvature and Refraction errors usually don't start appearing until you shoot distances greater than 500 feet. At a distance 1000', the error would be +/- 0.02 feet which for topographic surveys is insignificant.

Depending on the distances you measured, I bet that most of them were relatively short so you can foget about trying to correct the observations. The difference will be so small that it won't be worth the effort.
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