So...let's see what kind of mixed reviews we get here.....
What is the correct method when it comes to closing a traverse?
I've heard to tie in to your original backsight first then turn to your original occupy point from there. I've also heard shoot from your last point set on your traverse into your original occupy point and then set up on it and turn to your original backsight. I've even heard, albeit from a less reliable source of information, tie in to your original backsight only and go to the house!
Hmmm, so if you START with Line A_B, then you might close on line A_B, but either way, you MUST derive a bearing for line A_B when you start, and typically, you have ANOTHER name, for line A_B, such as line O_P, and the inverse of line A_B, and the inverse of line O_P, when subtracted, YIELD your angular closure. Some software, wants it to still be named line A_B, so that least squares can "Recognize" it. But, the traverse report of some software, generates you a "report" on how far you traversed, and what your closure was like.
(It does not matter, when you close FLAT all the time, LIKE I DO! (Wink!)
What does this have to do with RTK? (Bad joke!)
N
Turn angles @ all the traverse points (multiple sets if necessary, but at least direct and reverse), and shoot all the distances both directions (take several readings and mean them). Use the same number of angles and distances @ each setup. (you don't need to occupy the first setup more than once unless you are occupying all the setups more than once). You could occupy the first or another setup again if you have some doubts and think that setup might be suspect.
That's my opinion. If you can shoot across the traverse or to other points on the traverse from one setup, that's good too, but typically the whole reason you're traversing is because you cant see multiple locations from one setup.
The minimum requirement for "Closing a traverse" is when you set up on every traverse point and turn every angle and measure every leg.
This gives a coordinate closure and an angle closure.
Without having both, the adjustment process is close to being all guesswork.
Adjust the angular closure first and the coordinate closure should improve, if not the equipment with level bubbles probably needs adjusting. That is the most simple action.
Actually the analyzing part can get very involved and debatable in some cases.
:plumbbob:
Wouldn't the exact procedure depend on what your data collector software requires?
A Harris, post: 359240, member: 81 wrote: Adjust the angular closure first and the coordinate closure should improve......:plumbbob:
I disagree. Play around with the traverse, if you close on different setups (ie: make a different point your starting point every time you run the traverse). You'll find different closures. Reason being for every time you run it you are leaving out one angle to hit your closing angle and distance. adjusting out your angular misclosure will probably create a closure that is kind of in the middle of all the different ones. At that point you will get the same closure regardless of which point you start and end on.
If you did the first experiment, if one closure is much better than all the others, the angle you left out is probably the weakest angle and would deserve the most amount of adjustment if you were to weigh your adjustment of angles......
The sum of the internal angles of a triangle is always 180å¡...unless you have some error.
Measure all three angles and you can calculate your error... (N-2*180)
I occupy all three control points and measure all three angles.
If you intend to call it a traverse the closing angle should be turned. If you want to call it a network you have other options...
I haven't calculated a traverse in over 20 years. It's network or nothing for me.
Reset on your starting/closing point and reshoot the 2nd traverse point. That gives you more information if there is an angle bust or just out of range angle. If TP 1 and TP 2 reshots agree with the originals within your error budget, consider that a good traverse. If one is significantly larger error than the other, restudy all your angles sand distances.
I just finished a very nice open, more or less traverse. For TP 1 I backsighted a corner pipe and set TP 2. TP 2 to TP 3. At TP3 I set 4 (side traverse) 5 and 6. 5 was low giving me a shots at a structure and the opportunity o looking fro a corner initial recon could not find. 6 was high and in a field. I did not find the corner from 5 but did turn a set to 6. At 6 I shot 3 irons, set 7 near one iron in better view. At 7 I reshot the near iron and an iron across the field. I then set 8 over a crown. From 8 I shot my third set on one iron, shot 8 irons and a called for post then set 9 733' across and adjoiner to get 3 of his pins so I could confidently set a missing corner. I calc that corner and when I go back the snow has reduced and I see a small set stone, which was 0.1' from my calc coordinates. I then relook for my last missing corner and now see a pipe that was just not ringing through the snow. I shoot that from 6 and after final evaluation set an iron in a tree root 0.6' from my called for post. That gives mathematical harmony with two adjoining filed maps. My main PQ deed was original in perches and was perfectly converted to fee with perfect closure by adjusting all the angles.
Everything was under my error budget, not bad for the conditions.
Paul in PA
