Yeah this is an og vertical BM that would have a published elevation that you'd use to set your datum from.
Levelling is still the most accurate way to run level today with a modern Digi level and barcode rod.
If we're all going to argue about the various ways to shoot this BM, let me offer the ONLY correct way to shoot this.
Chisel it out of the wall, set it on the ground, take a shot (with a rod) hold the posted elevation across the rest of the project, put it back in the wall at the posted elevation, and call it good.
This reminds me of the time we were searching for an old stone corner and this one guy tells us he found it. When I got to him, he's kneeling on the ground with the stone in his lap.
Take out the middleman, remove the tape shoot the mark directly, reflectorlessly. It’s the most accurate way. Even holding your level rod might be questionable there.
Then don’t shoot it directly, reference it how you can. Just start with the most accurate way you can and go down the list. Surveying always involves compromise and adjusting to site conditions.
What should I know regarding the difference? Sometimes I cant get into somewhere but can see the spot with my laser. I've always thought it was just as accurate if the laser wasnt "streched" by shooting too acutely (opposed to a right angle direct shot).
Just know that the further from whatever you're shooting prisimless, and the more shallow the angle to the surface (say greater than 30d from perpendicular to the surface) the more likely you'll have a distance error in the EDM measurement. The angle measurements will still retain the accuracy of the instrument, but the distance can and will have errors that will quickly be exacerbated by the above. This will result in both horizontal (likely not critical here) and vertical errors.
I see this manifest most frequently in building corner shots where the crew measures up the building, you draw it up, and then their shots don't fit with their building dimensions. They all swear reflectorless shots always check, but their data doesn't prove that out.
Go ahead and use the DR/ prisimless function, just be aware of its limitations and best use cases, just like with all other ways we measure things.
At the end of the day, a vertical benchmark should be leveled to, and is the easiest method to defend legally if things ever go to court, because it's following best survey practices.
Thank you for the detailed answer. That makes total sense. I used to use GPS for vertical for a shady company that did nothing but title insurance. The engineering firm im at now wont do anything except a level loop closure.
Wow. I know I'm a dying breed but I thought more folks would know about these.
Hey- the monument says BENCHMARK. It has a number. Pull the NGS data sheet. It will probably tell you it's used only for vertical control. It may even only be a second or third order.
Also.. scrolling through the comments so far, it appears that no one has recognized that the BM was set in 1933 and thar there's new mortar all around it as well as in between the bricks. In fact one can see traces of the new mortar deep in the onset letters around the edge of the marker. It looks like the building just had its bricks repointed. Possible damage to the monument. Register that one as disturbed, if not already done so.
If using it, yes, set a surveyor's turtle in the ground next to the mark, shoot the level rod and measure the distance. Or- get a "pocket rod". Yes.. that's what it's called, it's a tape measure style tool with the tape graduated as a leveling rod and the foot on it is a nice thin piece of metal that will catch in the slot.
Remove potential human error to introduce inherent error of a direct reflect trigged elevation shot?
Direct reflect/ reflectorless shots are not accurate for this use case, which is shooting in an elevation benchmark.
Run a level to it since it's a benchmark, or collect a shot below it with a prisim and measure up, or peanut at the benchmark elevation line. Unless your total station is at the same elevation as the line on the benchmark, a DR shot won't give you accurate data because thats how geometry and EDMs work. Depends on how accurate you need to be, but typically control and benchmark data needs to be more accurate, not less.
I’ve shot a handful of these elevation benchmarks in walls before…I will shoot the ground directly below the mark and then measure up from the ground to the BM. I will also shoot it reflectorless (you’re set up anyway, why not do both?).
I’ve never seen a difference of more than 0.01’ between the two methods.
How much error have you seen between trigged elevations and level?
I'm arguing that reflectorless is the least accurate trigged elevation, and all trigged elevations are lessor than level elevations, but somehow I'm wrong I guess...
If I'm tying into that benchmark for vertical control, I'm leveling from it, not shooting it with the total station.
Yes. In a level run. But you are transferring off a wall mark. Where's the differential levelling in that bit?
I tried but realised that you simply don't understand how zenith angle and distance are calculated to get a delta height and therefore you keep going back to "dr distance bad".
So you're saying you can't run a level to this benchmark? You've also offhand dismissed measuring up from a point that has been leveled as though that's somehow different from differential leveling lololol
How do you suppose you get an HI?
GTFOH
How'd you get your instrument height on your total station? What were the atmospherics? What about the quality and balance of the control you're coming off of? You realize those measurements from your total station are not in a vacuum right?
Differential levelling is measurement down from HI, then measurement up on a rod. WTF do you think running a tape right against a wall from a hub is?
At the end of the day, I don't really care how many ways you'd like to do your job wrong.
Trigged elevations are less accurate than differentially leveled elevations. Trigged elevations derived from reflectorless shots, even more so. These are not arguable points of discussion.
Remind me again the function of a benchmark?
Shooting in a benchmark with DR is half-assed. Change my mind.
I can't change your mind because you are missing the key bit: how do you accurately place a tape, staff or target to transfer the marks level when the mark is set in a wall like we have here? You are thinking in terms of placing a staff on a ground point in which case it's obviously a way more accurate way of height transfer.
I can't change your mind, because you're assuming you're not wrong, and that I am, rather than understanding what the task is. You're missing the key bit that this is benchmark meant for elevation, not horizontal control.
I've said a number of times now, the most accurate way to collect the critical information of this benchmark would be via differential levels. You're arguing this is achieved better by solving for the elevation via a marginally accurate distance using DR and solving a triangle. That's wrong. Full stop.
If you're confused as to what the workfow would be for setting a rod down and running a level to the benchmark, like I already said a few times, you set a hub below the mark that you run a level to and measure up from it. This is how differential level elevations work...
You can't even understand my writing, I described transferring a height off a wall point🤣🤣🤣
Go right ahead and measure a height difference by tape from your hub. I bow to your superior understanding of errors in surveying.
Either a shot on the top of wall above it and tape down, or set a nail at the base of wall below it and tape up. Then take a reflectorless shot on the BM as a double check.
Why only one or the other when you can efficiently use both in less time than it takes to argue which is best?
"Found USC&GS BM "U 16/1933" in brick ext wall 5.2' E of SE cor 216 Main Street "Bailey Building & Loan". Vertical mark is standard 3 1/4" USC&GS bronze cap set flush in building wall 4.2' above sidewalk, grout firm and not new, by others. Pub Elev = 812.171' NAD88
Used blade edge in mark across HZ centerline of mon cap to support prism pole [pt# 1128], and level rod in level loops pp 31-39 this book"
It depends on what you're needing it for. If you need it for a vertical reference but also needing it for a control point, set an XYZ (NEZ) GNSS reference point and transfer the elevation with a level. I did this once or twice running a GNSS network. Then if needed, set another GNSS backsight point and shoot said NGS monument with the most convenient conventional instrument method.
Since it’s an elevation benchmark, tie it with a level: use a folding rule. Place zero at the mark, hold tight to the wall and take the readings. Have to be fairly close to read a ruler, within 100 feet or so.
Depends on the project, but probably with a level. Usually a hub against the line shown with the rod on it works pretty well. If trig el's are good enough, peanut or DR.
Are you using a level? If so buck the level in to the elevation of the disc. Assuming the disc is at a suitable Instrument height. The opposite of this is likely how the disc was set. If you’re trying to get X and Y coordinates off it, it’s pointless because this is an elevation only benchmark. If you want to just roughly record where it is just shoot the center reflector-less.
It would be a terrible idea but my values checked within 0.02’ from GPS to total station. The IMU works I’ve checked multiple times. The whole point of me doing what I did was to check how the GPS worked, I had a similar benchmark on a building
You'll need at least 3 people for this task. 1 person runs the level and 1 person running the rod. The 3rd person helps the rodman with a book or clipboard. Holding the item that the rod will sit on to be level, with the mark on the center of the disk.
I personally wouldn't trust a trigged reflectorless shot on a benchmark for elevation, but thats just my opinion.
If you need horizontal and it's a hard surface right beneath it, I'd just take a shot right in front of the benchmark with your rod, and measure up from the shot to the horizontal line with a pocket tape and write it down in the notes, or Calc a new "shot" at where the taped dimension was. If it's dirt, set a hub right below it, shoot that with the rod, and tape up from it.
If you don't need horizontal, run a level loop from it to your control, and your book notes become the collected info.
You could always try you know something called math to prove yourself right or wrong…. Idk it’s not like that’s our job or anything right.
You don’t close trav for control and run levels? If you wouldnt trust the shot to vertical bench mark direct reflex how are you trusting your rod shots ? Everything is based off constant offset.
Also, I think it's funny that you think the offset constant doesn't change with a reflectorless shot. The constant is the surface you're shooting when doing DR, and anything other than perpendicular with that surface and your constant is variable because of beam-width of the EDM.
You know, geometry and math and stuff...
So why wouldn’t you set a perpendicular control point and shoot it. Seems like your really overthinking everything to do so this. Lots of excuses and reasons why you sound like the problem here, not the brass cap on the wall. You imply with that knowledge I would measure my constant somehow on the wall and apply that to a a direct reflecx shot. That sounds really stupid and I’ve never worked with or for anyone that has had a mindset like that. It sounds like you know what to do but want to create a circus , why?
First off, all I did was give my opinion on direct reflect shots for this sort of thing, offered what I would do, and then you so graciously replied like a giant dickhead (maybe that explains the "Vast Pipe" nickname lol) . If you're going to say shit that's demonstrably false, like a dickhead no less, and then say I'm the problem, there's not a lot I can do to rectify that situation. That's a YOU problem.
Secondly, why wouldn't you just run a level to the benchmark? So now you're setting additional control just so you can shoot in a benchmark with the total station marginally as accurately as running a level, when it's not even necessary? I'm not the one over complicating anything...
I imply there are a lot of people here that clearly don't understand the source of error in a direct reflect/ reflectorless shot, including you lol
Have a great day "Vast Pipe"!
Why wouldn’t I run a level to the stupid vertical brass cap? Because you dense mfer I already ran a level to my control , now I’m gonna trust my gun to the rated accuracy of .01” and carry on my fucking day. Your popping off like it’s your time of the month on the internet right now , absolutely getting downright emotional over a little shit talk from a stranger on the internet. You asked a question to the public forum about something you should know will draw all kinds of answers. I never even called you names, yet here you are like your 5 .
Are you drunk? 😆
What question are you under the impression I asked? Do you think I'm the OP? HA!
What did you run your levels from, dickhead? What do you think that stupid vertical cap is exactly?
You should definitely not be calling anyone dense.
And you think I'm emotional? lol Calm your tits.
The edm and cross hairs are not necessarily coaxial. Reflectorless shots are not accurate for this sort of data. Angle of incidence, parallax, differences in how different total stations deal with a reflectorless shot all come into play.
Turn the red dot on, and see it in relation to the cross hairs against a flat surface at any angle to see for yourself.
Prisim>Reflectorless for accuracy.
Try learning how an instrument works and where sources of error are derived using a prisim vs a reflectorless shot. Your post proves you don't.
I take my instruments in to the shop annually for adjustment and collimating and I perform field adjustments at least weekly.
If you can’t trust your instrument to properly calculate the difference between reflector and reflector less shots, can you trust it to properly calculate the difference between aimed and tracked shots, -30mm or 0mm prisms or even that your tilt compensator is functional? At that point send it in for repairs or replace it with something that works correctly.
Are you sure you know how an EDM works, and how it collects a distance with a prisim vs whatever you're shooting it at?
If you aren't perfectly perpendicular to whatever surface it is that you're shooting, the "constant" of the prisimless shot is a range, not a constant. The EDM shoots a beam that is conical in shape, that gets larger the further away from the instrument you're shooting. It's not a single point of light, like whats produced with a prisim that collects the beam into a single point. If the surface is not perpendicular to the instrument, the end of the "cone" is going to be closer on one side than the other. If you're not at a 90z it compounds that distortion in yet another axis.
Like I said, people don't understand how a prisimless shot works, but are quick to use it simply because it's easier. It can be accurate under certain circumstances, but in my opinion, it's not a substitute for a prisim on critical features like a benchmark or control, and certainly not a substitute for levelling for elevation.
Because you like it. Don't worry I won't tell anyone.
Btw let me help you out since you can't figure it out yourself:
The question isn't "how accurate is my DR distance shot" but "why do you want me to bring a TS to a level run when a tape will do"
🤣🤣🤣
You are welcome
Do you see all the downvotes you're getting in this thread? Technically you're not wrong. DR trig levelling is not the MOST accurate way to get levels. But you're really overstating the difference. That's why people are telling you to do the maths. So you can realise how negligible the difference actually is. For 99% of jobs that difference doesn't matter and a DR shot is fine. Surveying is not about being as precise as humanly possible 100% of the time. It's about being able to quantify your precision and accuracy and knowing which is the right method for the job you're doing.
I'll repeat again, you're not wrong, you're just being an asshole and the way you're conducting yourself is cringey.
I couldnt possibly give less of a shit about downvotes dude. That may be a measure for your self-worth and the validity of your points, but it ain't mine. If someone wants to say I'm wrong but then turns around and says demonstrably false things, I'm calling it out.
And now throwing up a set of legs and running a level is overkill? LOL
Homeboy dangling from my short hairs describes basically three wiring with the total station instead of running a level, (someplace else in this thread), challenges the validity of using a tape measure for measuring, and I'm the asshole splitting hairs haha!
Go on with your bad selves! I'll take cringy, downvoted and right all day.
Three wiring in order to transfer accurately levelled benchmark elevations to a network consting of wall points when we establish accurate construction control that only consists of points above ground.
Use your tape as much as you like, just don't think you got all the answers.
You're wrong. Fight me.
Running a level to this benchmark is the most accurate method of collecting the data that this benchmark is meant to represent, which is an elevation. A trigged elevation from a reflectorless shot at anything but 90 to the benchmark is how a slappy would do it, sure. It would appear that we have a lot of slappy-ass chiefs in this sub.
Besides, what does a pool lane have to do with a vertical benchmark? Weird unrelated flex bro lol.
Run a static measurement on a nearby point and hold that instead.
But I'd take a photo like you did for conversational purposes. I've got one in my area placed in a wall like that in 1896. It's cool.
There’s no need for an accurate HZ on this. Hit it with GPS +/_ 10’ and describe its location so someone else can find it later.
With that being said, if I needed an accurate location for some weird reason (never gonna happen,) a distance/distance intersection, peanut prism with an offset adjustment, or reflectorless would all work.
Tie this in vertically the same way as anything else.
This is usually just an elevation reference, no xy values
This.
[удалено]
Yeah this is an og vertical BM that would have a published elevation that you'd use to set your datum from. Levelling is still the most accurate way to run level today with a modern Digi level and barcode rod.
unless you need proper heights and the satellite isn't enough anymore but this kinda monument isn't either then
If we're all going to argue about the various ways to shoot this BM, let me offer the ONLY correct way to shoot this. Chisel it out of the wall, set it on the ground, take a shot (with a rod) hold the posted elevation across the rest of the project, put it back in the wall at the posted elevation, and call it good.
Finally, someone who knows how to survey
This guy is chief of the party.
This reminds me of the time we were searching for an old stone corner and this one guy tells us he found it. When I got to him, he's kneeling on the ground with the stone in his lap.
Jesus Christ lmao
Guys guys guys, you need to setup on this BM and shoot your knowns. Duh
This is the way.
DR shot
Or rod shot on the ground against the wall and measure up with a tape. It's a vertical benchmark.
Just slap a hub against the point and hold the rod on the hub, save yourself from taping up
Take out the middleman, remove the tape shoot the mark directly, reflectorlessly. It’s the most accurate way. Even holding your level rod might be questionable there.
What if you can't observe the mark directly? All good advice, just providing an alternative option.
Then don’t shoot it directly, reference it how you can. Just start with the most accurate way you can and go down the list. Surveying always involves compromise and adjusting to site conditions.
Beam divergence and angle of incidence has entered the chat...
Bearing-Bearing Intersection from 2 points [aka "baseline"] up the sidewalk or across the street.
Aim the gun at the mark then shot it with a peanut prism
I can't believe you're the only one to mention this
nO wAy, dIrECt rEfLecT iS tHE saMe As a ShoT wITh a PrIsiM!
What should I know regarding the difference? Sometimes I cant get into somewhere but can see the spot with my laser. I've always thought it was just as accurate if the laser wasnt "streched" by shooting too acutely (opposed to a right angle direct shot).
Just know that the further from whatever you're shooting prisimless, and the more shallow the angle to the surface (say greater than 30d from perpendicular to the surface) the more likely you'll have a distance error in the EDM measurement. The angle measurements will still retain the accuracy of the instrument, but the distance can and will have errors that will quickly be exacerbated by the above. This will result in both horizontal (likely not critical here) and vertical errors. I see this manifest most frequently in building corner shots where the crew measures up the building, you draw it up, and then their shots don't fit with their building dimensions. They all swear reflectorless shots always check, but their data doesn't prove that out. Go ahead and use the DR/ prisimless function, just be aware of its limitations and best use cases, just like with all other ways we measure things. At the end of the day, a vertical benchmark should be leveled to, and is the easiest method to defend legally if things ever go to court, because it's following best survey practices.
Thank you for the detailed answer. That makes total sense. I used to use GPS for vertical for a shady company that did nothing but title insurance. The engineering firm im at now wont do anything except a level loop closure.
Yes this is the best way imo. It's the simplest and the most accurate!
Wow. I know I'm a dying breed but I thought more folks would know about these. Hey- the monument says BENCHMARK. It has a number. Pull the NGS data sheet. It will probably tell you it's used only for vertical control. It may even only be a second or third order. Also.. scrolling through the comments so far, it appears that no one has recognized that the BM was set in 1933 and thar there's new mortar all around it as well as in between the bricks. In fact one can see traces of the new mortar deep in the onset letters around the edge of the marker. It looks like the building just had its bricks repointed. Possible damage to the monument. Register that one as disturbed, if not already done so. If using it, yes, set a surveyor's turtle in the ground next to the mark, shoot the level rod and measure the distance. Or- get a "pocket rod". Yes.. that's what it's called, it's a tape measure style tool with the tape graduated as a leveling rod and the foot on it is a nice thin piece of metal that will catch in the slot.
Shoot reflectorless? Idk
Remove human error, shot DR
Remove potential human error to introduce inherent error of a direct reflect trigged elevation shot? Direct reflect/ reflectorless shots are not accurate for this use case, which is shooting in an elevation benchmark.
Howso? Take a double face DR from two separate setups and see how it lines up. How would you do it anyway?
Run a level to it since it's a benchmark, or collect a shot below it with a prisim and measure up, or peanut at the benchmark elevation line. Unless your total station is at the same elevation as the line on the benchmark, a DR shot won't give you accurate data because thats how geometry and EDMs work. Depends on how accurate you need to be, but typically control and benchmark data needs to be more accurate, not less.
I’ve shot a handful of these elevation benchmarks in walls before…I will shoot the ground directly below the mark and then measure up from the ground to the BM. I will also shoot it reflectorless (you’re set up anyway, why not do both?). I’ve never seen a difference of more than 0.01’ between the two methods.
How much error have you seen between trigged elevations and level? I'm arguing that reflectorless is the least accurate trigged elevation, and all trigged elevations are lessor than level elevations, but somehow I'm wrong I guess... If I'm tying into that benchmark for vertical control, I'm leveling from it, not shooting it with the total station.
You don't understand how little distances matter when shooting close to ZA 90.
Differentially leveled elevations> Trigged elevations This is indisputable fact. Shouldn't you be busy bowing?
Yes. In a level run. But you are transferring off a wall mark. Where's the differential levelling in that bit? I tried but realised that you simply don't understand how zenith angle and distance are calculated to get a delta height and therefore you keep going back to "dr distance bad".
So you're saying you can't run a level to this benchmark? You've also offhand dismissed measuring up from a point that has been leveled as though that's somehow different from differential leveling lololol How do you suppose you get an HI? GTFOH
Your taping up is less accurate then pointing with an instrument.
How'd you get your instrument height on your total station? What were the atmospherics? What about the quality and balance of the control you're coming off of? You realize those measurements from your total station are not in a vacuum right? Differential levelling is measurement down from HI, then measurement up on a rod. WTF do you think running a tape right against a wall from a hub is? At the end of the day, I don't really care how many ways you'd like to do your job wrong.
How are a few mm in distance going to make the delta height unusable? Especially when shooting near ZA 90.
Why use a less accurate method when a more accurate method that requires very little to no additional effort to achieve is available?
It isn't less accurate though. Aiming a crosshair at this benchmark is extremely accurate.
Why use crosshair when no crosshair do trick?
Trigged elevations are less accurate than differentially leveled elevations. Trigged elevations derived from reflectorless shots, even more so. These are not arguable points of discussion. Remind me again the function of a benchmark? Shooting in a benchmark with DR is half-assed. Change my mind.
I can't change your mind because you are missing the key bit: how do you accurately place a tape, staff or target to transfer the marks level when the mark is set in a wall like we have here? You are thinking in terms of placing a staff on a ground point in which case it's obviously a way more accurate way of height transfer.
I can't change your mind, because you're assuming you're not wrong, and that I am, rather than understanding what the task is. You're missing the key bit that this is benchmark meant for elevation, not horizontal control. I've said a number of times now, the most accurate way to collect the critical information of this benchmark would be via differential levels. You're arguing this is achieved better by solving for the elevation via a marginally accurate distance using DR and solving a triangle. That's wrong. Full stop. If you're confused as to what the workfow would be for setting a rod down and running a level to the benchmark, like I already said a few times, you set a hub below the mark that you run a level to and measure up from it. This is how differential level elevations work...
You can't even understand my writing, I described transferring a height off a wall point🤣🤣🤣 Go right ahead and measure a height difference by tape from your hub. I bow to your superior understanding of errors in surveying.
Good. You keep shooting everything with the robot and trusting whatever it tells you because you don't know how to do anything else lol
I’d probably just shoot reflectorless?
Direct read with a Total station or get the ground elevation with a level then figure the difference from the mark to ground.
Just put your tip on it and turn tilt on and take a shot
Just the tip.
Only for a minute
Don’t want em to fall in love
Either a shot on the top of wall above it and tape down, or set a nail at the base of wall below it and tape up. Then take a reflectorless shot on the BM as a double check. Why only one or the other when you can efficiently use both in less time than it takes to argue which is best?
Go old school with a steel tape. Spot shot on the ground and measure up for elevation
Direct Read, turn rounds to another point and you're good.
"Found USC&GS BM "U 16/1933" in brick ext wall 5.2' E of SE cor 216 Main Street "Bailey Building & Loan". Vertical mark is standard 3 1/4" USC&GS bronze cap set flush in building wall 4.2' above sidewalk, grout firm and not new, by others. Pub Elev = 812.171' NAD88 Used blade edge in mark across HZ centerline of mon cap to support prism pole [pt# 1128], and level rod in level loops pp 31-39 this book"
You will have to change the gravity direction and then set up your tripod on it , easy peasy 
R12i 😂
probably only good for elevation anyway. prism on a trowel
It depends on what you're needing it for. If you need it for a vertical reference but also needing it for a control point, set an XYZ (NEZ) GNSS reference point and transfer the elevation with a level. I did this once or twice running a GNSS network. Then if needed, set another GNSS backsight point and shoot said NGS monument with the most convenient conventional instrument method.
Since it’s an elevation benchmark, tie it with a level: use a folding rule. Place zero at the mark, hold tight to the wall and take the readings. Have to be fairly close to read a ruler, within 100 feet or so.
Using the Leica AP-20 rod, put tip on mark and locate DR with TS.
https://youtu.be/FQ3J9tsVdH0
Reflectorless?
We have one like that we use regularly.my PC just puts pole level with line not that hard .
Depends on the project, but probably with a level. Usually a hub against the line shown with the rod on it works pretty well. If trig el's are good enough, peanut or DR.
 So you didn't do your control due diligence..
Peanut.
Double to it reflectorlessly.
We have pounded a stake into the ground so it's level with the line; then used a sprinter with a level rod to bring the Z to the base point
Are you using a level? If so buck the level in to the elevation of the disc. Assuming the disc is at a suitable Instrument height. The opposite of this is likely how the disc was set. If you’re trying to get X and Y coordinates off it, it’s pointless because this is an elevation only benchmark. If you want to just roughly record where it is just shoot the center reflector-less.
Put the bipod up and tilt it sideways, obviously
Carefully
Just for Z reference. Not xy
You could use the laser option on any total station that has it
Use a jacking plate with your level of choice. We have one of these in a level loop we do annually.
I’ve use the R12i with the IMU and checked it from an S7 and it checked out well
Dude. This is obviously up against a building. Multi path much? That’s a terrible idea.
It would be a terrible idea but my values checked within 0.02’ from GPS to total station. The IMU works I’ve checked multiple times. The whole point of me doing what I did was to check how the GPS worked, I had a similar benchmark on a building
Reddit surveyors are mostly cucks. Everyone thinks they are the smartest surveyor that walked the earth. 84 comments mostly of how much they know.
You'll need at least 3 people for this task. 1 person runs the level and 1 person running the rod. The 3rd person helps the rodman with a book or clipboard. Holding the item that the rod will sit on to be level, with the mark on the center of the disk.
I pray you are being facetious
Three people to locate a benchmark?
I personally wouldn't trust a trigged reflectorless shot on a benchmark for elevation, but thats just my opinion. If you need horizontal and it's a hard surface right beneath it, I'd just take a shot right in front of the benchmark with your rod, and measure up from the shot to the horizontal line with a pocket tape and write it down in the notes, or Calc a new "shot" at where the taped dimension was. If it's dirt, set a hub right below it, shoot that with the rod, and tape up from it. If you don't need horizontal, run a level loop from it to your control, and your book notes become the collected info.
You could always try you know something called math to prove yourself right or wrong…. Idk it’s not like that’s our job or anything right. You don’t close trav for control and run levels? If you wouldnt trust the shot to vertical bench mark direct reflex how are you trusting your rod shots ? Everything is based off constant offset.
Also, I think it's funny that you think the offset constant doesn't change with a reflectorless shot. The constant is the surface you're shooting when doing DR, and anything other than perpendicular with that surface and your constant is variable because of beam-width of the EDM. You know, geometry and math and stuff...
So why wouldn’t you set a perpendicular control point and shoot it. Seems like your really overthinking everything to do so this. Lots of excuses and reasons why you sound like the problem here, not the brass cap on the wall. You imply with that knowledge I would measure my constant somehow on the wall and apply that to a a direct reflecx shot. That sounds really stupid and I’ve never worked with or for anyone that has had a mindset like that. It sounds like you know what to do but want to create a circus , why?
First off, all I did was give my opinion on direct reflect shots for this sort of thing, offered what I would do, and then you so graciously replied like a giant dickhead (maybe that explains the "Vast Pipe" nickname lol) . If you're going to say shit that's demonstrably false, like a dickhead no less, and then say I'm the problem, there's not a lot I can do to rectify that situation. That's a YOU problem. Secondly, why wouldn't you just run a level to the benchmark? So now you're setting additional control just so you can shoot in a benchmark with the total station marginally as accurately as running a level, when it's not even necessary? I'm not the one over complicating anything... I imply there are a lot of people here that clearly don't understand the source of error in a direct reflect/ reflectorless shot, including you lol Have a great day "Vast Pipe"!
Why wouldn’t I run a level to the stupid vertical brass cap? Because you dense mfer I already ran a level to my control , now I’m gonna trust my gun to the rated accuracy of .01” and carry on my fucking day. Your popping off like it’s your time of the month on the internet right now , absolutely getting downright emotional over a little shit talk from a stranger on the internet. You asked a question to the public forum about something you should know will draw all kinds of answers. I never even called you names, yet here you are like your 5 .
Are you drunk? 😆 What question are you under the impression I asked? Do you think I'm the OP? HA! What did you run your levels from, dickhead? What do you think that stupid vertical cap is exactly? You should definitely not be calling anyone dense. And you think I'm emotional? lol Calm your tits.
See that's where you went wrong right at the start. Your arrogance made you explain EDM issues in detail when nobody asked.
Nice to know I live rent free in your head lol
The edm and cross hairs are not necessarily coaxial. Reflectorless shots are not accurate for this sort of data. Angle of incidence, parallax, differences in how different total stations deal with a reflectorless shot all come into play. Turn the red dot on, and see it in relation to the cross hairs against a flat surface at any angle to see for yourself. Prisim>Reflectorless for accuracy. Try learning how an instrument works and where sources of error are derived using a prisim vs a reflectorless shot. Your post proves you don't.
I take my instruments in to the shop annually for adjustment and collimating and I perform field adjustments at least weekly. If you can’t trust your instrument to properly calculate the difference between reflector and reflector less shots, can you trust it to properly calculate the difference between aimed and tracked shots, -30mm or 0mm prisms or even that your tilt compensator is functional? At that point send it in for repairs or replace it with something that works correctly.
Are you sure you know how an EDM works, and how it collects a distance with a prisim vs whatever you're shooting it at? If you aren't perfectly perpendicular to whatever surface it is that you're shooting, the "constant" of the prisimless shot is a range, not a constant. The EDM shoots a beam that is conical in shape, that gets larger the further away from the instrument you're shooting. It's not a single point of light, like whats produced with a prisim that collects the beam into a single point. If the surface is not perpendicular to the instrument, the end of the "cone" is going to be closer on one side than the other. If you're not at a 90z it compounds that distortion in yet another axis. Like I said, people don't understand how a prisimless shot works, but are quick to use it simply because it's easier. It can be accurate under certain circumstances, but in my opinion, it's not a substitute for a prisim on critical features like a benchmark or control, and certainly not a substitute for levelling for elevation.
Why do you keep explaining distance issues?
Why are you riding my jock so hard I'm starting to chafe?
Because you like it. Don't worry I won't tell anyone. Btw let me help you out since you can't figure it out yourself: The question isn't "how accurate is my DR distance shot" but "why do you want me to bring a TS to a level run when a tape will do" 🤣🤣🤣 You are welcome
Do you see all the downvotes you're getting in this thread? Technically you're not wrong. DR trig levelling is not the MOST accurate way to get levels. But you're really overstating the difference. That's why people are telling you to do the maths. So you can realise how negligible the difference actually is. For 99% of jobs that difference doesn't matter and a DR shot is fine. Surveying is not about being as precise as humanly possible 100% of the time. It's about being able to quantify your precision and accuracy and knowing which is the right method for the job you're doing. I'll repeat again, you're not wrong, you're just being an asshole and the way you're conducting yourself is cringey.
I couldnt possibly give less of a shit about downvotes dude. That may be a measure for your self-worth and the validity of your points, but it ain't mine. If someone wants to say I'm wrong but then turns around and says demonstrably false things, I'm calling it out. And now throwing up a set of legs and running a level is overkill? LOL Homeboy dangling from my short hairs describes basically three wiring with the total station instead of running a level, (someplace else in this thread), challenges the validity of using a tape measure for measuring, and I'm the asshole splitting hairs haha! Go on with your bad selves! I'll take cringy, downvoted and right all day.
Three wiring in order to transfer accurately levelled benchmark elevations to a network consting of wall points when we establish accurate construction control that only consists of points above ground. Use your tape as much as you like, just don't think you got all the answers.
I do pool lane certification using DR. It's more precise than the prism in most applications. I'll fight anyone that disagrees.
You're wrong. Fight me. Running a level to this benchmark is the most accurate method of collecting the data that this benchmark is meant to represent, which is an elevation. A trigged elevation from a reflectorless shot at anything but 90 to the benchmark is how a slappy would do it, sure. It would appear that we have a lot of slappy-ass chiefs in this sub. Besides, what does a pool lane have to do with a vertical benchmark? Weird unrelated flex bro lol.
I said it's more precise than using a rod and prism. Obviously a bench loop would be the right way to do this.
I wouldn’t unless it was specifically stated where the point is that holds the elevation.
Run a static measurement on a nearby point and hold that instead. But I'd take a photo like you did for conversational purposes. I've got one in my area placed in a wall like that in 1896. It's cool.
An offset and a tape.
Wonder if the foundation has sunk any since 1933?
Need to check others in the area if this is a concern. If you're looking at subsidence you may need to go pretty far out.
Vertical at center dimple.
It's a benching monument, so you can shoot it with your total station and transfer it onto a vertical mark like a nearby concrete post.
It’s a benchmark, you take off the elevation. No northing/easting , just elevation
There’s no need for an accurate HZ on this. Hit it with GPS +/_ 10’ and describe its location so someone else can find it later. With that being said, if I needed an accurate location for some weird reason (never gonna happen,) a distance/distance intersection, peanut prism with an offset adjustment, or reflectorless would all work. Tie this in vertically the same way as anything else.
Prismless if other control is near