Trouble with vertical in traversing

[neOhiosrvyr]

Everytime I traverse when I check into my backsight I'm vertically off anywhere from 0.02' to 0.16' off usually low. I can run a whole loop and close horizontally fine but vertically never. Even if I run a level loop and put good elevations on my control points if I shoot a traverse point off the control whether its a hundred feet to a thousand feet if I check back into my backsight I'm off. The further the distance the worse it gets usually but not always. I use a Topcon GPT-3003W with a Carlson data collector and software if that helps.

 

[Apakrat]

Just a stab---
Consider the closure error is due to earth curvature imbalance of horizontal distances between vertical back sight and foresight.

At 74th year working on IR-One2 - - UHK PhD - - -

 

[cherrypicker]

Just another stab---

Have you taken enough readings on each face to compensate any errors in accuracy of the vertical circle of your instrument? If you are usually low it would initially suggest an error in your instrument if the readings are only taken on one face.

good luck...