Levelling with TS behaves strangely

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Levelling with TS behaves strangely

Postby sfd-surveytech » Fri Feb 11, 2011 4:44 am

Ok, I admit, everything I learned about doing Trigrinometric leveling with a Sokkia SET 500, a Carlson Surveyor and SurvCE 2.5 has been through trial and error, and after this post, I'm actually going to read the manual - outdated as it is (Yes Carlson, that is a plug).

However, because of trial and error, I have been able to complete two loops recently without having to entirely redo either loop. Mind you I had to manipulate the data and what gets processed, but I did get satisficatory results - though not as timely or painlessly as hoped.

My thinking (hoping) is that I have the data, and deleting a set of foresights to a point and redoing them and re-processing the data in not 'bad' practice.

My biggest problem seems to be with foresight turning points. On the first loop from the two above, I backsighted a previous TP, did a SS and then foresighted my next TP. The first shot was a bust, 0 SD. then the remainding 3 were garbage. After moving then backsighting that TP and foresighting my starting/ending BM, I learned that the TP elevation was wrong. So after reviewing the data, deleting first set of BS and FS shots, and retrying BS and FS shots twice. And lots of head scratching...I learned that the elevation for the last TP was just wrong and the only way to fix it was to reshoot it. :( Don't know what went wrong and how the VA was out to lunch on the three good shots but, it was. I even had an elevation on that TP from another source, so I had something to compare the calcuated elevation to! Another error, another lesson. After repeating the second last setup and the last setup, the loop closed satisfactorily.

On the second loop from the two above, same problem! Took a shot on the last TP as a FS. The shot went wonky - zero SD again! Expecting that it might be a problem - but hoping it wouldn't - and hoping that just deleting that shot would fix the problem, I proceeded to take 3 more shots. Moved to shoot that TP as a BS and found the problem I expected. Just deleting the first bad read to that TP as the FS did not fix the problem!After "deleting" that data, the program seemed to think it was a SS so it would not let me backsight it proprerly.So I had to 'undelete' the first FS to the TP and edit it to be the same as the other three foresights and finally after about 20 minutes of 'trials' I was able to get the program to realize that the TP had a reasonable elevation and was able to BS the TP. After that I was able to take another SS and close into my BM. Once again, I had to take a couple of trials at that too....

So, here are my questions:
- has anyone had simliar problems? If so, how did you overcome them?
- can anyone give some tips on good practices for trig leveling?
- does it sound like I'm doing anything wrong? (I'd like to think my practices are good, but I'm posting to learn and improve)
Posts: 15
Joined: Fri Feb 11, 2011 3:45 am
Location: Huntsville, Ontario


Postby sfd-surveytech » Sun Mar 20, 2011 11:37 am

typed up a nice update, but darn thing timed out or something and lost it! Will re-write offline and save it then paste it here!
Posts: 15
Joined: Fri Feb 11, 2011 3:45 am
Location: Huntsville, Ontario

Postby ron23 » Fri Apr 22, 2011 10:33 am

Yeah! Nowdays Total station is very popular instrument in the surveying due to its accuracy and also for the direct storing of the levels in the memory it save the time of manual writing. Thanks for your contribution it's really worth for me.

Material Safety Data Sheet Software
Posts: 1
Joined: Wed Apr 13, 2011 10:23 am

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