How to use modern surveying equipment?

[Stephen Tashiro]

I'm familiar with old fashioned optical surveying, but I've never tried to use modern equipment that is based on lasers. I see that "laser detectors" and laser levels are sold in hardware stores. Where on the web, can I find a good set of directions about measuring elevations with this equipment?

For example, I understand that the laser detector can be mounted on the typical "rod". But how is it used? Just looking at them, I'd guess that the rod man would hold the rod so the numbers faced him instead of the laser level. Then he would move the detector till it indicated a detection. The detector would display a horizontal line on its LCD display and the rod man would read the elevation from the rod that matched the horizontal line. That's just my imagining. Do things really work that way?

[AL Ursich]

I was a Chain-man as a Kid in High School in the early 70's. Worked as a Land Surveyor Helper, cutting the brush and setting the nail markers in the ground and using the plum bob calling my mark when on the point for bearing. Then holding the chain or metal tape measure with the plum bob on the mark for length. The Objective was to be able to plot all the data and after going around the property you ended up back at the first point.

I remember my Boss had the first Computer I had ever seen, the program was on a Cassette Player and when you turned on the Computer you loaded the application or program using the Cassette Tape.... That was 1972...

We did this big project and I remember the boss was Giddy with excitement as the outside track of the surveying had a 3 inch error of closure.... from starting measurement to the last back at the starting point. That told of the quality of our work.... A very high standard for the time....

With the Tape Measure you had to record the Air Temp since the 200 yard metal tape shrunk when cold and expanded when warm.

My Surveying skills helped me in the last 4 years of my Navy Career when we used Surveyor Transits to measure the roller path of the Radars, Guns, Missile Launchers and Gyros. We would work at Midnight as when the sun came up in the morning and the sun heated the ship on one side you could see the readings change as the ship Expanded on one side. We finished at Daylight.

Now to answer your question... They are putting a additional Gas Pipeline on our property next year. I had a chance to walk with the Surveyor Crew last winter marking out all the property lines.

The Theodolite or Transit had a Satellite GPS Receiver built in to the head, it also had a Laser Range finder and auto find. At setup, the head would level itself, position itself directly over the nail that the operator placed under the transit. It knew what direction to look that the Transit was previously setup on that now had a worker with a 6 foot Staff with a reflector in it. The Laser will see the reflector and lock up on it. The Transit noted the elevation and range to the previous spot. Then the operator swings the Transit to the general area of the new point and hits search... As soon as the Transit see's the Forward Staff reflector that the worker is sitting on the nail it locks in the bearing, range, and elevation.

Just as with Analog Theodolite, you record the Bearing, Elevation, Range, Height, but now it loads to a memory card.

As for the spinning laser levels, you level the head and turn it on and a laser spins on a level plane and you use a receiver that chirps when the laser hits it and you adjust the staff to record the numbers or distance between the laser beam and the ground.

Hope that helps....


With the Analog Transit of the 70's.... I remember the K&E Transit needed to go to Philly and get a replacement part and I went with my boss the 150 miles to Philly. After he fixed it he set it up to check everything. The Transit had a Magnetic Compass on it in the center and I saw the guy remove the top glass and move a balancing spiral weight on the tip end of the needle. I asked if the Tech should mark the starting position and he said no... This was the new balance point..... Well.... We get back home and setup and the needle of the compass was now nose diving and dragging it's tail on the glass cover...... I said to my Boss.... See... The Magnetic Field 150 miles away was just different enough that we needed to remove the glass cover in the field and move the Spiral weight on the Magnetic Arm...... or pointer....



AL

[Colin Giersberg]

We were to have a highway project this year (it may be assigned to a different crew now) that would use a piece of equipment that would scan the ground , download to a memory card, and generate its own cross-sections. I am sure there is more involved in the process, but that is what I had heard from a co-worker with the Alabama Dept. of Trans. What worries me is that technology isn't always reliable, so what happens when the equipment screws up, and we are the ones that have to figure out what went wrong, and how to fix it. Field books are not going to lose their memory, you have a hard copy that you can refer back to, and if there is a mistake in your notes, you can usually find it, and correct up.
We always seemed to be under pressure to get our cross-sections, and get out of the way so the contractor could start moving dirt. If the high tech equipment screws up, and the contractor has moved dirt, then there is no way of determining accurately how much dirt was moved for payment purposes. It seems like there needs to be a backup system in place just in case, and maybe there is.


Regards, Colin

[Stephen Tashiro]

It sounds like the modern transit does the process of "shooting stadia" automatically. My goal is to do a one man survey of my driveway. I'm interested in elevations, not boundaries. For that purpose, it sounds like what I want is a laser level, a rod and a laser detector. But I still don't understand if different types of detectors make it harder or easier for the rod man to read the elevation. What readings does the laser detector show besides "I see a laser"? Does it give a reading like "+2.05" inches? That means the rod man has to add that to the elevation of the location of the detector on the rod? Or does the rod man just slide the detector up and down the rod till it goes beep or something? I guess if the laser is bright enough, you could see where it hits the rod, but why would I need a laser detector then?

[Mike Henderson]

Seems to me that if you just want to shoot the elevation of a driveway, you should be able to do that with a builder's level and a long wooden ruler (maybe 6'). It would be best to have a helper to hold the stick, but you wouldn't need a lot of complex expensive equipment. I've done it by myself by propping the rule against something like the side of a short ladder.

Set the level up in a convenient position. Set up your ruler at the bottom of the driveway and take a reading. This is your base. Then put the ruler at different points along the driveway and take a reading (without moving the level). This will give you the elevations.

But if you're familiar with surveying you probably already know this...

Mike

[Stephen Tashiro]

What you suggest would be psychologically impossible for me.

You see, I have my fathers old 1960;s David White transit, elevation rod etc. The problem is that one of the bolts that lock the extending legs on the tripod for the transit broke. I looked for a new tripod locally but the ring on the old David White transit is larger than modern tripods accept. So I had a machine shop do a welding repair on the broken bolt (It has a head that looks like a big wing nut. It had lost a wing. ). When I got the repaired bolt back (several weeks later) I found that I had misplaced the little nut that goes on the other end. So I went looking for a replacement. The end of the bolt sits in a collar so I can't measure exactly what it size it is. My best guess is "7/16 ths -20". No local hardware store had this size. I went to "New Mexico Bolt And Screw", a fastener specialty store. The gentleman there pointed out that what I needed was a nut with a left handed thread. Arggh! He didn't have it.

Eventually, I'll find the missing nut and put together the tripod and the old outfit will be functional again. In the meantime, I'm not going to buy any mere "bulders level" or manipulate plastic tubing filled with colored water etc. when I already have a real transit. I will only buy new modern stuff. The basic purpose of having a hobby isn't to save money or even to do something. The purpose is to buy tools. Therefore, I return to my original question, which is: What features should I look for in a laser detector if my goal is to measure elevations? How are they used for this purpose?

[Peter Ellis]

Interesting thread, although I cannot help. I was only thinking the other day, as I passed some surveyors, that I wouldn't know what to do with current digital equipment, although I originally trained as a surveyor 40 years ago, but haven't done a land survey for something like 25.
I remember being fascinated by a promotional picture of the then latest Spectra-Physics laser mounted on a four screw base open framed Keuffel & Esser theodolite, that looked as if it was out of a museum and learning that it was a current model. The design had fallen out of favour in Europe probably before WWII, as four screw bases were prone to mis tightening and bending the base and had long been replaced in Europe by three screw ones with fully enclosed circles. American theodolites of the time were years behind European, particularly Swiss, German and British ones. Even the East German Carl Zeiss Jena ones were better. It seemed an odd combination of ancient and modern in the picture. Within a very short time the Japanese revolutionised the whole game and all the old manufacturers, unless they bought into digital technology, disappeared.

[Colin Giersberg]

Peter Ellis said "American theodolites of the time were years behind European, particularly Swiss, German and British ones. Even the East German Carl Zeiss Jena ones were better. It seemed an odd combination of ancient and modern in the picture. Within a very short time the Japanese revolutionised the whole game and all the old manufacturers, unless they bought into digital technology, disappeared."

The same can be said of power tools, cars, and several other things. Look at Bang and Olufson audio equipment. Biscuit joiners were used in Europe years before we adopted the technology. What about Festool with their system integration (the standard small Systainer can serve as an infeed and outfeed table for the Kapex), their saws and edge guides, and several other tools work together as a system. Do you see that with many manufacturers in the U.S. Up until this last year, Festool was the only company that did this. Will Dewalt and Makita come out with MFT tables., Systainers, etc.? I think Europe will continue to be several years ahead of us in technology, but that is just my opinion.

Regards, Colin

[Peter Ellis]

Hi Colin

My point really was that I was surprised at the juxtaposition of two very different levels of technology and coexisting. The Spectra-Physics laser sight was, at the time, leading edge and American technology. The instrument it was mounted on was 50 years prior. A lot of American technology was and is leading the world. There was evidently a reluctance in some technologies, though, to abandon what had worked for them in the past. It was true of British companies, too. Hilger & Watts continued to build more modern theodolites than K+E, but they were still failing to invest in the R&D that the Japanese were and by the time they realised that they needed to, it was too late. Their instruments were initially more robust than the Japanese ones were, with lots of heavy castings and bronze bearings, great for building Empire in remote parts of the world, where ruggedness mattered, but the Japanese auto collimation innovations were more in line with the future and each year the Japanese improved, taking more and more of the market. By the time H&W woke up, they could no longer afford the R&D, as they had lost too much market share.
The camera and motorcycle markets went the same way.

Cheers

Peter

[Scott T Smith]

The purpose is to buy tools. Therefore, I return to my original question, which is: What features should I look for in a laser detector if my goal is to measure elevations? How are they used for this purpose?

<grin> Stephen, I like the way you think!

Several years back I was in the position that you're in - i.e. what to evaluate about laser levels. In my case, I was interested in something that would allow me a one person operation, be durable, accurate over longer distances, maintain close tolerances, be self leveling, work either horizontally or vertically, send out beams both horizontally and vertically, and allow me to enter a slope. I came up with this list because my needs were 1) general building construction on my farm, 2 - rafter and roofing alignment (requires horizontal use), pole barn construction (cutting and aligning the tops of poles in the air) and outdoor grading work (pond dams, and a grass airstrip).

For most people, this list could be narrowed down a bit. Accuracy is important, especially over longer distances. Very high quality lasers can maintain 1/8" over several hundred feet.

Self leveling is a fantastic feature. My first laser had manual adjustments, and after setting it up the accuracy would change because of the sun hitting one side of the tripod and causing it to lengthen slightly. So over the course of a day I had to keep checking and releveling the darned thing! My second laser was self leveling and it will automatically sense a change, stop and relevel itself, and then start up again.

You NEED a receiver, unless you will only be working inside a dark building. It is not practical to see the rotating line out in the open - period.

Better quality receivers have a readout on both the front and the back, so that you can read the level against the rod from either side. This is really a nice feature to have. I actually purchased a second receiver to make it easier to lay out metal roofing (two people working simultaneously on both slopes of the roof).

You will have to do the math yourself in order to determine the grade changes, but it's easy. Typically I will take a measurement at the highest point first, and then go from there. For rough grading, rather than adjust the detector every time I move to a different location I will simply raise the rod to the point where the detector indicates that its level, and then make a quick estimate of the distance between the bottom of the rod and the ground. This lets me know how much fill to move in, and it's fast. Once I have completed rough grading, then I'll take the time to move the detector and record the differences between my reference point and actual.

Visually, "green" beam lasers are more visible than "red" beam lasers, but are currently more expensive.

I ended up purchasing the LMH 600 Lasermark from CST Berger. I've had mine for several years, used it frequently, with no complaints. Here is a link to some information about it:

http://www.cstberger.com/Products/LaserMark/LMH600.htm

You may not need the slope features on this product. I purchased the package and have used just about all of the features.

Hope this helps - good luck with your research.

Scott

[Stephen Tashiro]

Wow! It even has a remote! ToolKing sells a kit that includes the LMH600, tripod, the rod and a "target". I'll have to investigate whether a "target" is a laser detector - probably not.

[David G Baker]

I am happy with my old Berger optical level. Once in a while I could use a tripod to hold the stick when working alone.
I checked out the laser units but I don't do enough of the type of work that would justify the expense. The inexpensive ones aren't worth the trouble if you have to rely on your vision. Like Scott wrote, you will need a receiver.

[Steve Leverich]

Stephen, if you check out the above link it shows that only the 600D and 600PKG comes with a receiver. A "target" is just a red reflector that "lights up" when the laser hits it.

For DIY use, there are cheaper kits that include the receiver - I have one I got from HF a few years ago that was $300 including a receiver. Most receivers by themselves in this class run around $200-300, and if you're doing things outside in daylight you won't see the red laser at all. If you can wait til dusk, you can probably do without the receiver... Steve

Here's one from tool king that's less, still includes the receiver

http://www.toolking.com/dewalt_DW073KDR_reconditioned_cordless_interior_ex terior_rotary_laser_combo_kit.aspx