Wiggling in

[Wheelin]

I have an interview coming up in which the practical part of the exam will have me wiggling in on line between 2 points without the aid of a second person. Not having done this before, a kindly retired surveyor showed me how to do it, but I'm taking 12 1/2 minutes, and I've been informed that I have to do it in under 8 minutes to pass. From what I'm about to describe in what I learned how can I shorten my time?

1) pace the distance between the 2 line points.
2) pace 1/2 the distance to find the approximate mid point & make a mark with keel if on pavement, or some object if on dirt
3) using a measuring tape, pull the tape out 5 or 6 feet, lock the tape into place, and put the zero end of the tape on what you believe to be the line to one of the points respective to your position.
4) walk to the zero end of the tape and see how far off line the reel of the tape is to the other point. Adjust accordingly.
5) do a rough level of the gun using the optical or laser plummet (depending on what gun you're given) to sight on the tape measure.
6). Look at one of the end points and flop. Make a visual guess as to the distance you are off. Since you are roughly halfway between the two points, the distance you'll need to move is 1/2 the visual distance you are estimating.
7). Using the measuring tape, now place it perpendicular to the line so that the optical plummet is sighting on a round number, like 2.00 feet. Place a pencil at 1/2 the distance that was visually estimated in step 6 toward the line
8) using the visual distance estimated off line in step 6, look into the plummet and move the gun to the pencil position indicated in step 7.
9) Rough level, backsight a point and flop. If you are on the edge of the range pole set over the point, go ahead and do a fine level on the gun, and use double centering method.
9) estimate the visual distance again, and place pencil at 1/2 the distance along he tape measure.
10) Slide the gun on the base of the tripod to the pencil. Double center. You should be on line at this point.

Thoughts on how to shorten my time (other than starting a job in the gun, tagging the 2 end points, and setting out a line? They won't let me do that.)?

[Stan_K]

Are you allowed to use a calculator? Are you good at mental math? Is the terrain fairly level?
1) eye-ball the midpoint
2) quickly setup instrument
3) turn angle from BS to FS
4) sine of angle * distance = double the offline distance of instrument
5) using tape measure, measure perpendicular distance
6) move instrument, setup & level
7) repeat step 3 & 4
8) should be able to slide instrument on tripod for final adjustment

QUESTION: Is this really an exercise in wiggling-in or is it an exercise in how fast you setup an instrument? It normally requires 3 setups to complete the wiggling-in process. Some take 10 minutes just to setup the instrument-once!
Good luck.
Stan

[Peter Ehlert]

Thoughts on how to shorten my time

practice, practice, practice.

demonstrating your ability to quickly setup the gun and proceed in a logical manner will probably earn a very high score.

now turn off the computer, go outside, and practice, practice, practice.
good luck!

PS: Wiggling in is rather archaic, 40 years ago not many knew how to do it. you will probably be tested by an old fart like me. good luck!

[bruce hall]

try using a right angle prism to put yourself on line.

[Peter Ehlert]

good idea, a plum bob string works too.

[Wheelin]

Are you allowed to use a calculator? Are you good at mental math? Is the terrain fairly level?
1) eye-ball the midpoint
2) quickly setup instrument
3) turn angle from BS to FS
4) sine of angle * distance = double the offline distance of instrument
5) using tape measure, measure perpendicular distance
6) move instrument, setup & level
7) repeat step 3 & 4
8) should be able to slide instrument on tripod for final adjustment

QUESTION: Is this really an exercise in wiggling-in or is it an exercise in how fast you setup an instrument? It normally requires 3 setups to complete the wiggling-in process. Some take 10 minutes just to setup the instrument-once!
Good luck.
Stan

Thank you. To answer your question, I guess it's an exercise in both.

[Jim Frame]

Three things:

1. I've actually needed to wiggle in maybe 5 times in nearly 40 years of field work. Unless your employer works under unusual conditions, I question the value of this test as an indicator of pertinent ability.

2. In none of those instances was I able to pace between the endpoints. The reason I had to wiggle in was because access to the endpoints was impractical and/or I needed to setup in a particular spot in order to see a location of interest. Determining the midpoint would seem to be of little use in the real world.

3. Similar to the plumb bob string, a straight lath or other stick can be used as a rough sighting tool.

[Wheelin]

Three things:

1. I've actually needed to wiggle in maybe 5 times in nearly 40 years of field work. Unless your employer works under unusual conditions, I question the value of this test as an indicator of pertinent ability.

2. In none of those instances was I able to pace between the endpoints. The reason I had to wiggle in was because access to the endpoints was impractical and/or I needed to setup in a particular spot in order to see a location of interest. Determining the midpoint would seem to be of little use in the real world.

3. Similar to the plumb bob string, a straight lath or other stick can be used as a rough siting tool.

I agree with your point 1. There will (hopefully) be other tests with regards to pertinent ability, but unfortunately, they won't let the interviewee make the rules!

[Wheelin]

Thoughts on how to shorten my time

practice, practice, practice.

demonstrating your ability to quickly setup the gun and proceed in a logical manner will probably earn a very high score.

now turn off the computer, go outside, and practice, practice, practice.
good luck!

PS: Wiggling in is rather archaic, 40 years ago not many knew how to do it. you will probably be tested by an old fart like me. good luck!

I would love to practice! Do you have a total station that I can use? I, alas, am just a poor, struggling, career-switching, proletariat LSIT, struggling to make his way in the world.

[bruce hall]

been thinking about your situation and good luck with the 8.5 minutes. granted wiggling in shouldn't take "forever" and I guess two and a half minutes per set up would get you just under the allotted time. And that's if you are fortunate to make it in three tries, which is the best I could hope for (well maybe one setup is the best case, but that's never happened to me). I have wiggled in countless times and is not a big deal. never was on a clock and don't want to be (surveying is not a race although I have to get the job completed). hurry, hurry gets me in trouble.

Be methodical with a purpose and you should be fine. forget about the stop watch. If you are in the OC you can borrow my T16 and a set of legs and I will give you two lath that you can plumb over the end points. You will have to provide your own pocket tape, red head and watch.

[Wheelin]

Thank you very much for your generous offer. The interview came & went. I feel like I bombed it, but despite my bruised ego, I view it all as a positive...or an "opportunity to learn". If you don't mind, though, I'll definitely take a rain check on your offer.

[D Ryan]

Don't feel bad. Everyone else probably did about the same. Kind of a silly test in this day and age. And similar to what Jim said, if the two points were in close proximity, you'd just set up on one and sight the other. I can only guess they were using this to test your overall ingenuity and understanding of the principles involved, and not whether you could really wiggle in that quick. Looking on the bright side, maybe you showed them something they weren't expecting.

Dave Ryan,
Humboldt County

[Wheelin]

Thank you. One of the beauties of getting older is that I'm getting too tired to dedicate too much energy to negativity. Best just to move on. I feel thankful that I'm still employed; many others have it much worse.

[Gary Schenk]

I'm surprised they didn't have you adjust a solar compass.

How often will you need to wiggle in a scanner?

[pls7809]

Kind of funny, but one of the first field tasks I had to do as a survey intern for LA Dept. of Water & Power was learn how to wiggle in to do a deformation survey on a dam. Monuments were set at the ends of the axis line on the hills on each side and the way they measured the horizontal movement for this particular dam was to wiggle in and then measure offsets to the monuments set on the dam itself. I only did it the one time and I have never done it since.