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Traverse Angle Adjustment
I want to distribute a positive 6 second angular closure error in a closed link traverse with 6 stations. My common sense tells me to subtract 1 second per angle and rerun the traverse. However, a YouTube video says to distribute the error proportionately. Like this
Line 1-2: -6″ x 1/6 = -1″
Line 2-3: -6″ x 2/6 = -2″
Line 3-4: -6″ x 3/6 = -3″
Line 4-5: -6″ x 4/6 = -4″
Line 5-6: -6″ x 5/6 = -5″
Line 6-7: -6″ x 6/6 = -6″
The closing azimuth is supposed to be flat, but it isn’t. What’s the correct way to do this?
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6 Replies
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There is no one right way to do it. The way you initially suggest is the common way. But you could arbitrarily decide to throw it all in one angle – perhaps because you knew the setups was mushy and/or the sightings were obscured at one station. The youtube method you describe sounds undefensible. But perhaps you are misunderstanding? If the calculated adjustments were applied to the azimuth of the legs rather than the turned angles, then it would work.
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This reply was modified 2 months, 4 weeks ago by Norman_Oklahoma.
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This reply was modified 2 months, 4 weeks ago by
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@ Norman_Oklahoma
Maybe I did misunderstand the YouTube video. Probably the same angle adjustment logic is good for any kind of closed traverse. I forgot about being aware of sighting low over grass, or some other condition that could affect an angle. Nothing suspicious on this particular job. Thanks for responding.
MH -
If this is a straight-forward traverse (no cross ties), I’d simply calculate it with raw data, do a compass rule adjustment and inverse the final numbers to make sure nothing got changed enough to cause a problem. You can of course do a Least Squares adjustment, that’s difficult without a program.
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@ Norman_Oklahoma
I found something questionable. I subtracted 6″ from the setup with a short BS.
MH -
For the record, 6 seconds misclosure on a 6 legged traverse is infinitesimally tiny. Even with a 1 second gun, as the 1 second rating is for a pointing, not an angle. And the gun is only one part of the system. I’d be inclined to push ahead without adjusting angles at all, as Moe suggests.
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What Norman said in his last post.
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