by **Darcy Detlor** » Sun Nov 21, 2004 11:29 am

I think that we are concerned about wording, when all we need to is provide a solution to the problem. Our definition of a "Closed Loop Traverse" is designed for a special case. Our "Open" traverse actually "closes" to a known point with an option of a closing foresight angle. This allows you to adjust angles. It is a still a "closed" traverse.

Our definition of "Closed Loop" traverse was originally created to simplify data entry. It is no different from our "Open" Traverse except there is no need to enter in some extra information because we know that the starting backsight point is the last point where you set up the instrument. It means no more than that. When you choose our "Closed Loop" traverse we define the starting backsight point and the original setup (POB) point as fixed and immovable points. You are actually closing on the BS point. Therefore the leg between the two is not part of the loop. The first angle from the backsight to the second setup is used for the angular calculations, and the last foresight shot angle (back to the POB) is used to compute the angular calculation, but the leg between the two is not part of the traverse, because the points are fixed relative to each other. The closure computation is the distance traversed from the first setup point to the point where the error is measured, which in this case is the distance between the last setup coordinate and the starting BS coordinate, divided by that distance error.

If you use the "Open" option, which is "open" only in the respect that you have to enter in a little bit more information, you will get the results you want, but the leg between the starting backsight point and the initial setup (POB) will be adjusted, and the starting backsight point will move.

I believe we could discuss the wording for quite a while, and it is possible that we would change the terms slightly, but in reality we offer several scenarios in our documentation which cover just about every possibility. As Glen stated, I think that you want to use the "Open" method to compute the results the way you want them.