Trimble Access an S6 and a Closed Traverse

Access can adjust & close a traverse for you automatically, so long as there are no really bad blunders, by running the Traverse procedure under COGO. If I remember correctly, when you re-shoot & occupy the initial setup point to close, you must use the same point number. Anyone feel free to fill in the gaps, I'm not completely familiar with it.

If it's a closed loop you should set up on your initial station and turn closing angles backsighting the last station and foresighting the initial backsight point. Always use the same point numbers for the same points in Access/TBC.

If it's an open traverse between, say, two GPS pairs, designate them as Control points if you want to close it in Access. Obviously, any slop in the GPS points will get thrown into your traverse if you adjust it.

You can close the traverse in the field in Access, or adjust it in TBC. I find the TBC Compass adjustment to be pretty wonky, but they just put it in there so hopefully they'll improve it. It's amazing how many things are easier to do in Access than they are in TBC.

If you close it in Access you can get a raw closure, then balance the angles and get an adjusted closure, then perform a Compass rule adjustment.

The office has us use a different point name for our tie in station. If the first station was 900, when we shoot it as a FS we store it under, say 10900.

We then occupy 10900, turn to original BS, say it was 901, and call it 10901.

This is for being run through Starnet though, wasn't sure if you DID in fact intend on closing it AND adjusting in the collector.

I'm curious what anybody else might think about this procedure. I'm not saying it's the best, only it's what we are told to do. I've told them I can adjust it in the collector myself, they sneered at that as if it were blasphemous!

If I was the office LS responsible for your work I'd want to see the raw positional and angular misclosures, which the point numbering system you describe easily allows.

BajaOR, post: 345157, member: 9139 wrote: If I was the office LS responsible for your work I'd want to see the raw positional and angular misclosures, which the point numbering system you describe easily allows.

I find it to be a head scratcher why you have to use the same 900 number in the traverse cogo function. :-S It feels to me like you're almost abandoning the traverse you just ran. Kind of like resetting zeroes before you shoot a checkshot. I suppose the collector knows what is going on and accounts for it, but I've never had the chance to experiment with it.

Lee D, post: 345124, member: 7971 wrote: If it's a closed loop you should set up on your initial station and turn closing angles backsighting the last station and foresighting the initial backsight point. Always use the same point numbers for the same points in Access/TBC.

If it's an open traverse between, say, two GPS pairs, designate them as Control points if you want to close it in Access. Obviously, any slop in the GPS points will get thrown into your traverse if you adjust it.

You can close the traverse in the field in Access, or adjust it in TBC. I find the TBC Compass adjustment to be pretty wonky, but they just put it in there so hopefully they'll improve it. It's amazing how many things are easier to do in Access than they are in TBC.

If you close it in Access you can get a raw closure, then balance the angles and get an adjusted closure, then perform a Compass rule adjustment.

If using the sample below of a sketch of a recent traverse I start a new job in an assumed system scale factor being 1.0 applying. Station setup creating a point number one at N:5k E:5k Elevation=100 do I leave the control point check box unchecked?
And take a compass reading to my back sight and I apply it to the azimuth to my back sight which will be point number 2 that will then give a coordinate to the point after it records the distance and vertical angle.

I then set point 3 once I move ahead to point 2 back suggesting 1 and so fourth.

Do I then come back around and when occupied on 5 I do an averaged observation f1/f2 to point number 1. Then average the data? Or do I go into the Cogo menu and choose traverse at this point?

Do I have to make sure these closing point numbers (6 aka 1) or (7 aka 2) are a certain assigned number or can they be whatever number as long as it's the same number that I originally started my job with such as 1 and 2?

From there I think I understand what I need to do as far closure. I just want make sure I take the proper steps getting there.

In that scenario - a closed traverse with no external reference - I would start out with the instrument either at 1 backsighting 5 and foresighting 2 or at 2 backsighting 1 and foresighting 3. I would traverse around until I was re-occupying my first occupied point and then turn closing angles. So if my first setup was at 1 backsighting 5 and foresighting 2, my last setup would also be at 1 backsighting 5 and foresighting 2. And I would call them 1 and 2 both times through. You could check Control on the first point but it shouldn't really matter.

My preferred method would be to have my first backsight to an external reference. Let's assume that in your scenario there's a radio tower to the NNE of point 1. I would set up on 1, get my compass bearing to the tower, backsight it as point 2, and observe it either Angles Only or Horizontal Angle Only. I would then foresight point 3. Using Measure Rounds, I would turn sets direct and reverse at each point - occupy 3, backsight 1, foresight 4, etc. - until I came back to point 1. My closing angles would then be backsighting 5, foresighting 2. Does that make sense?

Also figuring out how to traverse with Access, I followed the previous post's method and it worked very well - first backsight to an external reference as horizontal angle only, turning sets throughout the traverse, and closing by foresighting the same ext reference. But I had a question and haven't yet tried: could I turn rounds directly from a station setup plus (using the single backsight option, and the foresight as the additional point), as opposed to completing a station set up, and then measuring rounds? Or does this mess up either the station setup or the traverse functions in Access and TBC?

Can anyone help explain this difference in viewing traverse results within Access and TBC?

This was a short 4 station closed traverse in a parking lot, roughly 200x300. I closed it within Access.

A) In DC, on the "Close Results" screen, it showed angular close of 11", distance close 0.002', and precision 1:443,874.
B) I exported a Traverse Report from Access, and it there I see: adjusted (compass), angular misclosure 0", distance misclosure 0.011', and precision 1:89,057.

Then, from TBC, I can highlight the traverse and in properties see the same 1:89,057, etc. data as in the Traverse Report (B).
I can also chose Adjust Network, where I see the "Before Adjustment" information same as in "Close Results" (A), as well as "After Angular Adjustment" information: angular misclosure 0", distance misclosures (N,E,Z each a few thousandths), and precision H 1:375286 and V 1:613745.

Are the various reports and info just viewing the steps along raw -> angular adjusted closure - > compass adjustment?