Traverse job!!

I could calc it if you recorded your distances, angles, etc. with pencil and paper. If so, please post them. If you recorded them electronically with a data collector, I couldn't do it but someone else could.

Take a picture of the notes with your phone. Then attach that photo to another post here.

That's the thing.  Not sure what angles to get.  That's where I am lost. I have azimuth.  Thr angles not sure which angles to get as there is different ways of getting angles.  There was no note. Just did the setups. 

Just to clarify. were you using a total station instrument? And if so, what exactly did you do at each point where you set it up? What other points did you sight, and what readings did you take?

1.) Make a list of each Azimuth with its Distance in the order that you measured them.

2.) Draw a rough sketch of the shape of your traverse and place each AZ-Dist at the proper line on your sketch.

3.) Take a photo and post it here.

The OP caused me a flash back to my very first traverse run in school with a total station, an HP48 and cogo card. The guy teaching had never run a traverse before in his life, handed us the equipment with instructions to 'figure it out'. Half the class quit but a few of us, with the help of one of the students who had some basic understanding as his father was a surveyor, eventually puzzled it out. So my question is, how far along in that process is the OP? Now it's second nature, but back then?

@rplumb314 

No actual notes were taken.  Was not sure what angles to write which I was hoping trimble business center would allow me to manually enter points for a traverse but was a fail. Here is what I ended up getting in TBC.  Hope I can more insight on the actual notes to get.  Always willing to learn even if I dont use it again. 

Posted by: @frankg

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@rplumb314 

No actual notes were taken.  Was not sure what angles to write which I was hoping trimble business center would allow me to manually enter points for a traverse but was a fail. Here is what I ended up getting in TBC.  Hope I can more insight on the actual notes to get.  Always willing to learn even if I dont use it again. 

-- attachment is not available --

 

Good job on the angle measurements. One at each station. Closed figure. Now you just need distances on those lines in order to compute your point coordinates around the figure and calculate the closure.

You seem to be running an azimuth traverse. That is, you are setting the azimuth of the back sight as your "zero" and turning to the foresight, and the reading is the foresight azimuth. This simplifies some calculations, but makes doubling of angles all but impossible. So most of us set zero as the angle to the backsight, measure the angle (and not the azimuth)  and let our computers add the measured angle to the backsight azimuth to compute the azimuth to the foresight. 

In your example the angles at each station may be reverse engineered from the differences in the azimuths.  And the sum of the interior angles in a four side figure, in theory, will add up to exactly 360°. Field measured angles will not add up to that exact figure because no work is perfect, but yours do. So I'm assuming that these are not all field measured values. 

Nevertheless, the noted distances do not quite result in a closed figure. The "misclosure" is about 0.035 feet. The sum of the lengths of the legs of the traverse is 536.49 feet. So the misclosure  is 1:15,328

0.035/536.49=1/x

0.035x=536.49 x 1

x=536.49/0.035

x=15328    

The points plcbk1 and plcbk2 were shot in w8th GPS.  Points plcbk3, plcbk4 and plcbk2 tv were done in the field with a total station

Really just need some notes and angles so the inspector can turn that assignment in.  Im not worried about it for myself. Any help is really appreciated

Just out of curiosity, are you running this traverse using Access (since you appear to be a Trimble shop with TBC) or some other variety of field controller/software? If that is the case, you should have a raw data file associated with your traverse that would have all of your measurements. Those measurements would be contained in the .job file imported into TBC. Many times I've run traverses and just booked all of the measured angles and distances and computed the traverse off of those. Your post reaffirms for me traversing is becoming something of a lost art with todays dependency on GNSS for everything. Really you need to go out with someone who knows what they're doing and run a traverse with them so you have a better handle on everything. I really loved running long traverses through the woods and over hill and dale and closing tight has always been a real rush for me.  

scs900 was used. No traverse module to use.  I will post a csv file if someone can help with some calc and drawing tomorrow.  And now i didnot do mulitple face turn on each point.  realized i am suppose to do that after it was done.  Usually do two face turns but as this was a quick show and tell setup.  I was able to pull up an email with the csv file of the points. 

 @frankg, this is the .csv file displayed in Excel, with a header added--

You mentioned that PLCBK1 and PLCBK2 are the two points set with GPS. Then there's PLCBK1 TV, which is perhaps a duplicate point set at PLCBK1. It's different by 0.009 ft. Then there's PLCBK2 TV, which perhaps was set after traversing through PLCBK3 and PLCBK4. If that's the case, PLCBK2 TV is a closing point, and what we have is an open traverse between the two GPS points. Does this correspond to what you did in the field?

It's important not to mix up field measurements with data that was input or calculated later. The closure calc should be applied to field measurements only. It's not possible to include the GPS points in a traverse closure because they're not part of a traverse.

PLCBK2 and PLCBK2TV are different by 0.028 ft.

Or to make things simpler. Just so she can finish this part of the survey training.  Does anyone want to share one of their traverse. Feel free to pm.  Be much appreciated 

@frankg

Here's a plot, of sorts. From what you've said, it doesn't seem as though the two GPS points, PLCBK1 and PLCBK2, were actually included in the traverse. So I plotted it as an open traverse beginning and ending at those points.

Because there were no angles measured at PLCBK1 and PLCBK2, it isn't possible to adjust the angles and calculate the closure of a four-sided traverse in the usual way.

I didn't compute a closure error or closure ratio, because the traverse wasn't closed. The usual purpose of computing the closure error is to get an idea of how accurate the field work was.

As @Norman_Oklahoma said, it appears you read azimuths in running the traverse. From those it was possible to compute two angles, as shown.

We don't know the accuracy of the GPS distance. However, the closing distance of the open traverse agrees with it very closely. So in effect the GPS and the traverse give a check on each other.

It's possible that both the GPS and the traverse are in error by a similar, larger amount, but that's very unlikely. From what can be seen here, it looks as though the field work was quite accurate.

Sounds as though the instructions for this assignment may not have been very detailed.

It doesn't look like she's being trained at all. I agree with an earlier post that traversing is becoming a lost art. I've done more than I can remember. The difference in azimuths will give you angles, but if you don't understand the traverse method (and mix methods such as subbing in GNSS shots), it's just a muddle. I hope the answers given for your figures have helped.

The keys to a good traverse are consistency and redundancy. Repeat measurements made the same way throughout the loop or line if an open traverse. Best of luck.