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Disadvantages to running resection vs normal setup
a-harris replied 7 years, 4 months ago 41 Members · 93 Replies
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billvhill, post: 421725, member: 8398 wrote: In my experience a resectionat at 900 feet is too far for vertical, maybe not for dirt work but for buildings, I would use a level. I would also beware of doing more than one resection on the same building. It doesn’t mean much if one building is a little off from another but within the same building it does. I would set the daily control with the GPS just as you mentioned, occupy a point and backsight another and use that for each building. That’s one thing I miss about using Leica, being able to shoot the same point multiple times.
Please don’t mention inches on this site” should be banned from construction, period. We had a new civil engineering join us 2 years ago who is obsessed with decimal inches. I argued this, as it was drilled into me in college that inches are ONLY fractions, NEVER decimal. Turned into a summer of debate.
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Luke J. Crawford, post: 422179, member: 11382 wrote: ” should be banned from construction, period. We had a new civil engineering join us 2 years ago who is obsessed with decimal inches. I argued this, as it was drilled into me in college that inches are ONLY fractions, NEVER decimal. Turned into a summer of debate.
Not disagreeing with that.. it adds way more confusion than needed. The best is when half the plans are in inches and the other half decimal feet. It’s just asking for something to be built wrong. That being said… I do slip on occasion but only because I’m so used to saying it for 10 hours a day 6 days a week. Telling a carpenter a bolt has to move 15 thousandths is probably the worst idea ever. Telling him it has to move 15 thousandths NORTH will get you a punch in the face
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You have to know how your software is working also. Older versions of TDS would change your angle and distances (that you just measured) to work with the distance between control points resecting from. That works fine if you know the control is perfect 🙂 but if it wasn’t perfect you got some wild answers. On that software I would use side angle side formula to solve triangle manually. It is my understanding that newer field software seems to be better at reporting differences and asking what the user wants to hold. Jp
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elkboarder, post: 422208, member: 12485 wrote: Not disagreeing with that.. it adds way more confusion than needed. The best is when half the plans are in inches and the other half decimal feet. It’s just asking for something to be built wrong. That being said… I do slip on occasion but only because I’m so used to saying it for 10 hours a day 6 days a week. Telling a carpenter a bolt has to move 15 thousandths is probably the worst idea ever. Telling him it has to move 15 thousandths NORTH will get you a punch in the face
I had to do an as built once (in the days before total stations) where we had to locate things in feet and decimal feet along a baseline (stationing), and then the offsets from the baseline in feet and inches. Engineer specs.
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How many remember the old days of “angle only” resections? Needed at least three, and it was very sensitive to geometry. I think that is why some people have a mistaken view about the accuracy of modern resections. I have done some of that off of radio towers and water tanks that had coordinates in the days before GPS. Good for å± a few feet, rough position only.
But now with three or more points, and accurate total stations, plus on board least squares solutions, one can have high confidence in the results.
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elkboarder, post: 421940, member: 12485 wrote: Wow thanks Paul in pa.. your insight has been very helpful. I wasn’t aware this forum was going to contain so many people looking to stroke their egos than actually help but hey whatever helps you think you’re the smartest in the room
Um, it affects our replies. I worked in Chicago, I have run a TRANSIT for many years. With a 200′ and 300′ tape.
Honestly, do you mean TOTAL STATION?
BTW, you will get into alot of things here, on this forum, including Surveyor’s Emotional Troubles…. It seems that this forum is a one stop shop, for Wine, Women, Wives, GPS, Transits, Least Squares Adjustment, and dead cats. And, you are trying to teach an “Old Dog” a new trick…. ie, your other party chief.
So, you may need a surveyor psychologist, or a Psychiatrist. However, there are proctologists, masquerading as genuine surveyor psychs!MAYBE your other party chief, has experience with this, and is hesitant to change his ways….
🙂
Surveyors, and party chiefs have delicate egos too.
N
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John Hamilton, post: 422217, member: 640 wrote: How many remember the old days of “angle only” resections? Needed at least three, and it was very sensitive to geometry. I think that is why some people have a mistaken view about the accuracy of modern resections. I have done some of that off of radio towers and water tanks that had coordinates in the days before GPS. Good for å± a few feet, rough position only.
But now with three or more points, and accurate total stations, plus on board least squares solutions, one can have high confidence in the results.
I think John likely has nailed it. Resection, with an EDM, ie total station, with DISTANCE is way better.
I bet this is WHY your other PC is not on board with Resection.N
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Nate The Surveyor, post: 422229, member: 291 wrote: Um, it affects our replies. I worked in Chicago, I have run a TRANSIT for many years. With a 200′ and 300′ tape.
Honestly, do you mean TOTAL STATION?
BTW, you will get into alot of things here, on this forum, including Surveyor’s Emotional Troubles…. It seems that this forum is a one stop shop, for Wine, Women, Wives, GPS, Transits, Least Squares Adjustment, and dead cats. And, you are trying to teach an “Old Dog” a new trick…. ie, your other party chief.
So, you may need a surveyor psychologist, or a Psychiatrist. However, there are proctologists, masquerading as genuine surveyor psychs!MAYBE your other party chief, has experience with this, and is hesitant to change his ways….
🙂
Surveyors, and party chiefs have delicate egos too.
N
You’re right, I should have clarified that I meant total station. I’m new to the site and will use proper terminology moving forward. The response from Paul in PA is what got to me. He could have easily said something along the lines of “are you using a total station or actual transit?” There was no need for the arrogance. I will say though, if I’m going to catch grief if I put a comma in the wrong spot while posting then I’d prefer those types of people to not even read my discussions. My intent is to start a conversation, learn some things and help others learn as well which is what I thought this forum was all about. I do not act like a know it all because I’m not. I care a lot about my profession and want to do the best job I can but if I’m going to have to analyze every word of every post I create so that I don’t sound dumb to someone who is just itching to call me out on stuff then I won’t bother posting anymore.
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elkboarder,
I’ve been around this forum for many years, and a few before this one. One thing to remember is that we all have different personalities. You sometimes have to have thick skin on here. I don’t take too much of what is said on here to personally. I have had to wade through a few discussions before to learn something. Don’t let anyone get to you, and you can learn a lot here. Hang around, and you’ll get used to this rowdy bunch, and gain some knowledge.
Welcome to the forum!
Jimmy
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Elkboarder- I think your problem may have nothing to do with resections. Sounds to me that he just doesn’t respect you as a supervisor or acknowledge that you are “in charge” this is often a problem when a younger less experienced person is purportedly “in charge” of someone more experienced
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Jimmy- thanks, I’m liking the site so far, just not some of the negativity but you’re right.
Roger- (that’s a pretty awesome profile picture by the way) But..that is what’s going on. It’s a messed up situation because this project has been non stop for the past year. About 3 months into it he up and quit with one weeks notice, which as you all know is pretty much the same thing as quitting with no notice at all so it was up to me to keep the client and do the work of two crews which I worked my A** off for months after to keep everyone happy. The project go to the point where just I could not do it anymore and we needed a guy that knew what he was doing so we ended up bringing him back on. The pessimist in me thinks he quit hoping I’d struggle and then we’d call him back within a week and he could re-negotiate his pay but I ended up doing it with just one other guy who we brought on as a helper for months. So yes, I do think that he does not have as much respect for me as our other guys out there. All that being said, I guess I kind of make it seem like we are at each others throats all day. That’s not the case at all. We actually get along well and for the most part it is a nice balance. I show him things he’s not used to using like digital levels and he shows me things I haven’t done since college.
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elkboarder, post: 422208, member: 12485 wrote: Not disagreeing with that.. it adds way more confusion than needed. The best is when half the plans are in inches and the other half decimal feet. It’s just asking for something to be built wrong. That being said… I do slip on occasion but only because I’m so used to saying it for 10 hours a day 6 days a week. Telling a carpenter a bolt has to move 15 thousandths is probably the worst idea ever. Telling him it has to move 15 thousandths NORTH will get you a punch in the face
Truth in that.
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I did maybe 2 resections in my 1st 10 years of surveying and those were for rough work. I got SurvCE about 3 years ago (had always been SurveyPro user),started reading about it’s least squares resection routine with ability to set standard deviations, researched the S out of best practices for such things and I now use it all the time. Ive done same resects with CE & SP then checked other points. CE does it better, or at least it lies better….
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Some references I’ve found-
http://geomtours.blogspot.com.au/2015/06/free-station-resection-with-2-reference.html
Larry Best, post: 421947, member: 763 wrote: I think one reason some of us “more experienced” surveyors don’t use resection is that before field computers it would have been too tedious to calculate in the field. SurvCE makes it very easy to use and understand the errors. One thing I recently realized is that the LS solution gives the same weight to varying distances, I think. When setting up between 2 points, one close and one much farther, I would like to proportion the errors to the distances. Can I do this? Am I missing something?
CE is great because it does weight the measurements based on the standard deviations you set for each sight.
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Comparison of methods:
- Angular resection and triangulation: only bearings are measured to the known points.
- Trilateration: only distances are measured to the known points.
- Free stationing and triangulateration: both bearings and distances are measured to the known points
I believe the OP is talking strictly about the 3rd, using D&B for position calculation.
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Nate The Surveyor, post: 422229, member: 291 wrote: Um, it affects our replies. I worked in Chicago, I have run a TRANSIT for many years. With a 200′ and 300′ tape.
Honestly, do you mean TOTAL STATION?
BTW, you will get into alot of things here, on this forum, including Surveyor’s Emotional Troubles…. It seems that this forum is a one stop shop, for Wine, Women, Wives, GPS, Transits, Least Squares Adjustment, and dead cats. And, you are trying to teach an “Old Dog” a new trick…. ie, your other party chief.
So, you may need a surveyor psychologist, or a Psychiatrist. However, there are proctologists, masquerading as genuine surveyor psychs!MAYBE your other party chief, has experience with this, and is hesitant to change his ways….
🙂
Surveyors, and party chiefs have delicate egos too.
N
A lot of the NYC guys run only transits on high rise work still. I get a lot of funny looks when they see my 1″ robot, like it’s from Area51 and is obviously is a “commie plot” that can’t be trusted.
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elkboarder, post: 421679, member: 12485 wrote: Hi everyone. I am currently having a little bit of an argument with one of our more experienced field crew members. He’s been surveying for 15+ years and in my opinion has some bad habits that he refuses to unlearn. One of these is his firm belief that resections should and I quote “only be done when there are no other options” We are currently working a very very busy construction site with more equipment and machines blocking our line of site than I can describe. This just so happens to be our busiest part of the project, we are both crew chiefs however I am the lead in this project. He is very stubborn and more than likely upset that a 30 year old is trying to tell him how to do his job. I normally would not tell anyone how to do their job as long as they were not screwing anything up however his method of setting on the same two points repeatedly and setting points off this setup if something is in his line of site is starting to just get silly and I believe he is introducing more error into what he is laying out than needed. Behind the project is a large ridge that we have control on (traversed control.) For the past two months I set two backsites on whichever points will give me the best angle and then run my resection and lay out whatever it is I’m laying out. 90% of my layout work is foundations and anchor bolts. I do this for many reasons and will list them. I would just like anyone’s input on if any of my theories are flawed because I’m trying to really figure out why he’s so against them.
1. With resections you can set up right next to what you’re laying out
2. You are establishing control while at the same time setting up for your layout, saving time.
3. With you being so close to what you’re laying out the error decreases. When I stake out my backsite which is 900′ away after an hour and see an error of .04′ I know that that error is much less on what I’m laying out because of how close I am.
4. Easier to re-level the transit when it’s sitting 20′ away from you.
5. Resections help to average out error in setups.
6. We get a lot of different tasks throughout the day usually I lay out a foundation with 40 anchor bolts in about an hour and then get a call to do the same thing 150′ away from where I’m at. This allows me to pick up by transit, move to where I need to be, turn the glass on my backsites if need be and run a new resection.With all of these advantages I just don’t understand his thinking. I do (and not bragging here) but at least double the work he does throughout the day because of this method and it’s actually starting to make me mad because part of me thinks he’s doing it on purpose so he doesn’t have to work as much. Half his day is figuring out control dilemmas where I never have that problem. The way this site is setup is we have a fixed GPS base and are running a local coordinate system. The GPS is calibrated to our traverse so everything jives well. Whenever I stake out one of my control points of something I’ve laid out from a resection it always hits tight. I guess I’m just looking for others opinions on this issue and to hopefully gain a little insight on why he may be so against them.
ThanksStraight from the Swiss minds… I’ve given this to a few co-workers, only partially as a joke. Page 33 may be all her needs.
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Elkboarder, you can get a comma wrong… and get picked on… Hey, I recommend a some asbestos and a bit of salt….
wear the asbestos, and put the salt in some of the “salt free” advice…I okuzionally speel thigs wrong… just to anoy the speeling perlice!!
🙂
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Hey mate,
As stated numerous times, there is no problem with conducting a resection for construction set out. I actually prefer it as you are able to set control in positions which are outside the scope of works, less likely to be disturbed by heavy plant. As stated earlier also, you will be eliminating centering errors which are much more likely than a error in a careful resection. Your train of thought in setting the jigger up close to the area you are marking also greatly reduces the error aswell, as whatever small errors you have in a resection will be insignificant if you have a significantly lower distance to your set out points.I’ve been using reflective targets for resections on long term sites for a few years now, and I find that I’m getting consistently tighter miscloses than setting up over marks. even though I do have to check the condition of these targets regularly, and I’m generally shooting at the very least 3 targets double faced, it is a huge time saver which makes it a worthwhile exercise when all things are considered. It’s also made it easier for me to teach our operators how to setup instruments for machine guidance as they tend to get frustrated when setting up over a mark.
I’d be talking to your boss about the issue as it seems more like he’s too proud to be working under the supervision of a “junior” surveyor in his eyes. This is much more likely to be the issue, and you don’t want his lack of work to reflect on the firm as a whole because it will affect everyone, not just the stubborn employee.
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Haha! Finally someone else who calls a Total Station a Jigger! It’s good to see another Aussie in here.
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