I'm using a Trimble S7 with Access software on a TSC5. I have known points A and B, there is a hill between 2 points and i don't have free line of sight, therefore a resection is not possible. My solution was to create an intermediate point C with coordinates, then setup on C, back sight to A, then set another intermediate point D, then move the instrument to point D, setup, back sight to C and keep doing this until I take a shot to point B.
I can start my topographic survey and when done, back in the office, I can rotate the boundary to match with the original location of points A and B.
I know there is a method in Trimble Access which i can do the adjustment on the fly and NOT post- survey. The instruction on Trimble help is not clear to me. Is the traverse adjustment possible on the fly and not the way I have done it in the office?
IMHO there is no way to adjust your traverse until you have made that final tie to point B. I do not use Trimble but like you I always do the adjustment in the office where I can save all the points to a new file (keeping the original data separate) and then rotate and translate all the points to the line A-B and often times there is an elevation adjustment also. Much easier and safer to adjust in the office.
I set up with an arbitrary set of coordinates, complete the traverse, then analyse the observations with least squares analysis, fixing points a and b.
Can't you just setup on the hill and "wiggle in"? I think that's what they used to call it.
My approach with only a dc would be to run a random link traverse and then translate and rotate the resultant coordinates, as a group, onto the fixed points. BAM! But I haven't done so in years because I much prefer to do these sorts of things in the office. BTW - doing this with StarNet (or any similar package) is a slam dunk.
Couple of ways to do it with Access with both involving using the translate/rotate function. My preferred method would be to set up where I can see either A or B and use a reverse compass bearing to cogo out the station coordinates for my set up using a measured horizontal and vertical distance. Then change to making A or B my backsight, run the traverse and collect topo. Finally close into the other point. Since a compass bearing was used, you'll have to rotate everything onto the second control point holding the first but likely only a couple of degrees, then check the vertical against the second point to make sure that misclosure is tolerable. The second method would be to run a completely independent traverse off the two points using an assumed xyz and translate, rotate the whole kit and caboodle to match up with the control points A & B. If the misclosure is tolerable and you want to adjust, easy enough to prorate the error into your setups, but if it's within a tenth for topo I wouldn't bother messing with it. Either way, easy-peasy.
Just because I'm paranoid, doesn't mean they aren't out to get me.
Can't you just setup on the hill and "wiggle in"? I think that's what they used to call it.
You are definitely old school. Yes, that’s what they used to call it. AKA “bucking in.” I’ve done it several times.
@field-dog No Way, Point A is around a corner, then comes the hill , on the other side is point B.
@sarkiss The Traverse adjustment routine in Access is probably not what you need. It is intended to adjust a fully closed loop where all the angles have been observed. The missing line technique mentioned by @landbutcher464mhz and @pfirmst is the way to go - assuming you can't beg or borrow a GNSS receiver that is
I did the adjustment in the office. I hate to move points, so I ended up moving the boundary to match with the shots taken at points A and B.
Thank you guys!
I did the adjustment in the office. I hate to move points, so I ended up moving the boundary to match with the shots taken at points A and B
The coordinate number values change with just the punch of a button to match the coordinates on A & B. Changing the boundary coordinates is a bad idea IMHO.
No Way, Point A is around a corner, then comes the hill , on the other side is point B.
In that case I'd probably just run a loop around the site I'm topoing, passing through A & B along the way. The traverse points would just become control points to go with the topo.
I hate to move points, so I ended up moving the boundary to match with the shots taken at points A and B.
I move boundary linework onto monuments I tied all the time, that's SOP for me.
@sarkiss Before moving any points, always have a backup plan if things go sideways. It's my preference once I have a boundary nailed down based on monuments on the ground and tied into my control network, to lock that stuff down and don't mess with it since I'm working with real world coordinates. In my book, the topo is orders of magnitude lower in importance to my control and boundary resolution. If I'm going to gob something up I'd much rather have it be a few topo shots as opposed to accidently moving one of my control points or monument ties that constitute my boundary framework, and not catch it.
Just because I'm paranoid, doesn't mean they aren't out to get me.
@williwaw I always work with local coordinates. I don't have any gps device. I rather move the boundary lines than any points shots taken.
If you wish to save time a traverse like that can be adjusted in the field in 5-10 minutes.
Old school, since there are no cross ties, and no angle closure a compass rule will adjust it the same as a non-weighted least square adjustment.
Check book math; doesn't take hardly any time.
Can't you just setup on the hill and "wiggle in"? I think that's what they used to call it.
Nice. Wiggle in and buck in were common practices when I started.