Digital Level (Land Surveying)

by hillsidesurveyor @, MN, IA, WI, Friday, October 04, 2013, 17:10 (607 days ago)

I have been thinking about moving to a digital level, but have never used one or even know how they operate.

Some of the questions I have are:

Are digital levels more accurate than a standard automatic level?

Do you need special software to download the data, or can you get direct readings from the level and book it like a standard level?

We are currently using surveypro software that has a leveling option on it. Is this for a digital level?

Have been using a standard Topcon level for years that has treated me very well, but there is always a rounding error when running long loops. I would think that a digital level would eliminate the human error when reading between the lines so to speak.

I have been so used to looking up benchmarks in the field book from level loops, it may be hard to switch to having things switched to a digital format.


Thanks for any replies.

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by Norman Oklahoma ⌂ @, Portland, Oregon, Friday, October 04, 2013, 17:23 (607 days ago) @ hillsidesurveyor

Are digital levels more accurate than a standard automatic level?

Very much so. Loop closures under 0.01' are normal. If you get closures greater than that it is because your turning points aren't stable.

Do you need special software to download the data, or can you get direct readings from the level and book it like a standard level?

You aim, press a button, and get the rod read out. Book as normal. Super simple to use. Some models will carry the elevation. At lot will record to SD cards or some such which most laptops can accept. All depends on what you want.

--
Lord, help me be the person my dog thinks I am.

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by Jim Frame @, Davis, CA, Friday, October 04, 2013, 17:39 (607 days ago) @ Norman Oklahoma

You aim, press a button, and get the rod read out. Book as normal. Super simple to use. Some models will carry the elevation. At lot will record to SD cards or some such which most laptops can accept. All depends on what you want.

With the Leicas you'll probably want to use software if you choose not to book the data. The Leica output is ASCII, but it's pretty cryptic. If you're handy with programming it's not too hard to write your own, but you'll spend a fair amount of time with the GSI manual before you get anywhere.

--
Jim Frame
Frame Surveying & Mapping
609 A Street
Davis, CA 95616

Digital Level

by Equivocator, Brisbane, QLD, Australia, Monday, October 07, 2013, 15:41 (604 days ago) @ Jim Frame

DNA Series spits it out in excel format if you tell it too. Nicely formatted, booked and reduced.
The Sprinters require you to use the 'Sprinter Dataloader' program, which is (as you said) required if you want to be able to read the data.

Digital Level

by callen @, Indiana, Friday, October 04, 2013, 17:37 (607 days ago) @ hillsidesurveyor

I've seen millimeters reasonably attainable with right equipment and procedures, and seen it repeated. I'm a believer based on limited experience, but not an expert.

Be sure you have a DC with software to support it, or test drive the onboard software.

I've seen guys resort back to hand field notes because the "included" software was so user un-friendly after they got into it. You still get better results easier, but part of the bonus is also the efficiency. You may still need field notes for detailed point descriptions.

Been a while since I ran one, but it seems like Trimble's DiNi would store shots and even run closures and adjust for you all in the level. It's kind of funny seeing 0.002' "adjusted" out of points in a run for most purposes, but technically it is correct to adjust first, and round off to your desired accuracy at the end.

Digital Level

by Justin Maloney @, Cambridge, MA, Friday, October 04, 2013, 17:54 (607 days ago) @ hillsidesurveyor

Yes, a digital level is much more accurate than an equivalent standard level. With decent turning points expect typical closures of 1-3 thousandths without much effort.

For most loops I just write down the data in the notebook, but it's much faster because all the math is already done for you. You will also know instantly if your closure is off, and it will give you the rod distance as well. I would only bother with downloading the data if I was spending all day doing levels. The newer models use flash or SD cards and probably have more than enough space to save decades worth of data if you ever need to look it up.

I haven't used a data collector with the level before but the Surveypro level module is for digital levels. I imagine it's pretty simple to run, there isn't a whole lot to leveling unless you're doing specialized adjustments.

If you do levels with any regularity a digital level is a very good investment. The elimination of reading and calculation errors is the main benefit, and the better accuracy and quicker operation is just icing on the cake.

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by B.L. HINDMAN @, Antlers, Oklahoma, Friday, October 04, 2013, 18:04 (607 days ago) @ hillsidesurveyor

I have ran 12 mile check levels with a leica digital level. With a hundreth difference. Used the LGO software to download and excel to adjust.

ITS THE WAY TO GO! ;-)

Digital Level

by Beavers @, Nebraska, Friday, October 04, 2013, 18:52 (607 days ago) @ B.L. HINDMAN

I have used a Leica digital level some, and like others have said it can be a pain to learn.

I was always lucky enough to avoid being the guy to run the long level loops.
Our crews that did run the long 10-20 mile level loops always closed within a hundy or two. They are faster than three wire even with a good I-man and dead nuts accurate.

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by Bill93 @, 52402, Tuesday, October 08, 2013, 08:26 (603 days ago) @ B.L. HINDMAN

A tight closure is necessary but not sufficient. I'm not arguing against digital levels. If you can always hold a tight closure, then you can believe it. But I'm never impressed by a single closure no matter how good.

You occasionally get an accidental near-perfect closure. I've run between two NGS bench marks to see if one was "replanted" when the ties didn't seem to match the data sheet. I closed 0.006 ft using a middle-grade Topcon auto level and 3-wire readings estimated to hundredths on a topo rod. Was the data that good? No way. I was hoping to get maybe 0.050 ft. The rest was the luck of the draw.

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by Beer Legs @, Milky Way Galaxy, Planet Earth, USA, Friday, October 04, 2013, 18:09 (607 days ago) @ hillsidesurveyor

Generally you should be able to use a data collector which is nice because it records the data. My 1998 HP-48 with Survey Pro even operates our Topcon DL-102C. Expect to get closures in the thousands using good procedures.

--
Never build a wire gate tighter than the wife can close. - Baxter Black.

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by Steve Corley @, Little Rock, Arkansas, Friday, October 04, 2013, 18:23 (607 days ago) @ Beer Legs

We have been using Leica Digital levels since back in the 90's. We currently use a DNA 10, and get second order closures using fiberglass rods. We had to Blue Book a project last year. Since we did not have the equipment to do the Blue Booking, Invar Rods and the 1st order level, we had one of our survey contractors who wanted to get into that type work do the leveling and Blue Booking. We had a recent run between 2 benchmarks with our DNA 10 and fiberglass rods. Our numbers were very close to what they got with a DNA 01, Invar Rods and turning turtles. We just turn on a big screw driver driven in the ground. We store the data, but usually book it too, and depend on the book unless there is a problem. I have adjusted a few networks with Star Lev.

--
Steve Corley
steve dot c dot corley at sbcglobal dot net

Digital Level

by SIR VEYSALOT, Friday, October 04, 2013, 19:44 (607 days ago) @ hillsidesurveyor

Ran a level loop with a Nikon 520 side by side with a high-end trimble digital level. Through a river valley 2 miles in length 200' vertical. Tied within .01 same as Trimble. My one turn covered three of their turns.

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by roveryan @, Enschede Netherlands, Saturday, October 05, 2013, 04:41 (606 days ago) @ SIR VEYSALOT

get a digital level with accuracy specification of 1st order. then get a pair of those level rod base stabilizers. use them even on hard surfaces and your closures will be less than 0.003 mm for 1km loops.

Digital Level

by Richard Davidson, Tuesday, October 08, 2013, 07:33 (603 days ago) @ roveryan

"...and your closures will be less than 0.003 mm for 1km loops..."

Is this a typo?

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by roveryan @, Enschede Netherlands, Tuesday, October 08, 2013, 15:43 (603 days ago) @ Richard Davidson

yes a typo shoul be .003 m to enter 1st order prescision

Digital Level

by party chef @, Saturday, October 05, 2013, 07:18 (606 days ago) @ hillsidesurveyor

If you have never used one you should try renting one for a day before committing. The closures are crazy good and it is nice not having to book all the data but using one is a bit more finicky than a auto level. The level needs to be able to see a pretty big swath of the bar-code so it is not like a Philly rod where you just need a little hole and can raise for red to pick the foot up, also light conditions are a bigger constraint especially in areas where the light will be speckled like with sun falling through tree canopy.

To my mind the digital is the way to go, if it has specs tighter than can be measured with a total station I would go straight to digital, but in some applications a regular level can't be beat.

Too bad they all look ugly now a days, I like the look of the old wild ones better. I have only used Wild/Leica models but found the Leica one to be pretty hip, you can print the raw out so it is pretty much the same as a field book which makes it easy to follow.

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by paden cash ⌂ @, The Great State of Oklahoma, Saturday, October 05, 2013, 07:51 (606 days ago) @ party chef

I don't remember what model we had at the State, but they were Leica/ Wild. In 1995 I ran 18 miles from Alva, OK to Cherokee, OK on SH14; and then turned back.

36 miles of levels checked 19mm before any adjustment. It will make a believer out of the harshest critic. I can only assume they make them a little better nowadays.

--
"Never miss a good chance to shut up."

Will Rogers, 1879-1935, American Humorist

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by Frank Willis ⌂ @, Alexandria, LA, Sunday, October 06, 2013, 08:37 (605 days ago) @ party chef

I totally agree with all said above regarding accuracy. I also agree with Party Chef that visibility on the rod is important. If you are running in the woods or on steep slopes where you can't see a lot of the rod you will get tired of it very quickly. But where you have good rod visibility there is nothing better. The first time I checked closure using one on an 8-mile loop, I did not believe it was that accurate-but it was.

--
www.willisengineering.com

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by Cliff Mugnier ⌂ @, Baton Rouge, Louisiana, Sunday, October 06, 2013, 14:13 (605 days ago) @ Frank Willis

LSU has two Zeiss/Trimble units. One is used for optical tooling metrology, one for geodetic levelling. Good stuff & reliable. We use second-party software for geodetic applications that we purchased years ago from Charles Whalen; don't know if it's still available.

Difficulties concerning visibility with the Leica units I think has been corrected.

--
Cliff Mugnier
Surveying, Geodesy, & Photogrammetry
LOUISIANA STATE UNIVERSITY

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by Jim Frame @, Davis, CA, Sunday, October 06, 2013, 14:29 (605 days ago) @ Cliff Mugnier

Difficulties concerning visibility with the Leica units I think has been corrected.

Corrected when, and is the fix via firmware update? I've run into it a few times with my DNA03. It was serviced last year, but I don't recall if they updated the firmware.

--
Jim Frame
Frame Surveying & Mapping
609 A Street
Davis, CA 95616

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by Norman Oklahoma ⌂ @, Portland, Oregon, Sunday, October 06, 2013, 17:29 (605 days ago) @ Jim Frame

Corrected when ...

I've used the Leica NA2002, which needed a nearly unobstructed field of view of the rod to read, and a Leica DNA03, which is much more forgiving but still needs a good sized hole.

--
Lord, help me be the person my dog thinks I am.

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by roveryan @, Enschede Netherlands, Monday, October 07, 2013, 15:56 (604 days ago) @ Norman Oklahoma

i don't understand the problem about rod visibility. You are doing a level run not a topography survey where you need to measure the exact point feature on the ground. If you can't sse the rod then move it to a visible area. So you add another set of BS FS to the total observation data.

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by Norman Oklahoma ⌂ @, Portland, Oregon, Monday, October 07, 2013, 20:53 (604 days ago) @ roveryan

i don't understand the problem about rod visibility.

It is a minor annoyance only.

--
Lord, help me be the person my dog thinks I am.

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by Frank Willis ⌂ @, Alexandria, LA, Tuesday, October 08, 2013, 06:39 (603 days ago) @ roveryan

I think the problem stems from the terrain you are in in the Netherlands as compared to Louisiana, which can be like surveying in the Amazon at times. Lots of vegetation and it would often take too long to clear it out of the way as opposed to seeing an optical target through small breaks in vegetation.

--
www.willisengineering.com

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by Carl Zeiss, Sunday, October 06, 2013, 17:39 (605 days ago) @ party chef

I haven't used a digital level for eleven or twelve years.

My last run was with a Leica NA3000. It was a 26km run through NGS first order mons (3), through 2 second order mons, to close on a first order mon. Closure in 26 km was 1.2mm.

That's about the worst result I had with it. I ran a rod and the crew, not the level.

Even then Leica had field book format software which I used. I don't understand the issue about that.

Although I have good memories about my 1970's i-man Ralph, the digital level never read the wrong foot on Monday mornings.

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by Frank Willis ⌂ @, Alexandria, LA, Tuesday, October 08, 2013, 07:14 (603 days ago) @ Carl Zeiss

That kind of closure is about what I got when I finished a job of approx. similar size. I just did not believe it. It is incredible how precise these things are.

--
www.willisengineering.com

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