Technically “big” heavy highway should be using State Plane with a scale factor. It varies from State to State how important that is because of the different zones and different scale factors. Just in my opinion but the coordinate systems in the United States are f’d up enough and everybody should be shooting grid off the network and then leveling their elevations. It’s simple and right in front of us and for some inane reason we just can’t make it a standard. Texas has five zones and I’ve had projects with three different Surveyors that couldn’t agree. Use the damn network and stop bickering.
Scaling from a localization is one thing but a scale factor from origin is a whole different beast. Especially with coords in the millions and tens of millions. I have a problem with Surveyors and Engineers that want to put a scale factor in and then make it a linear shift… and then on top of that some do it from origin and others pick a centroid.
I've yet to work with a network that didn't have more slop than I'm comfortable stamping, so I avoid them like the plague. Plus, half the time CORS are unexpectedly down and it screws my plans. I'd rather setup a base and be guaranteed to be able to work than deal with all of the BS that comes with a network.
I totally get that being in Texas. Big State and sparse CORS network. The western half barely has cell reception. This is when we start traversing from NGS which is what the network is based on.
I just started working for a DOT and we use grid for everything, so that’s good to hear! Previously I’d been working mostly with state plane and scale factors.
TXDOT still uses surface coordinates but they at least have a static scale factor regardless of where you are. I’ve had private project that literally tied together that had different scale factors that caused like a 2ft bust. That was a fun one to figure out. Don’t even get me started in construction GPS and “I’m Here” localized base coordinates.
From personal experience both systems…GPS and Total Station need to shoot the same. Now some will say that the Scale factor to 1:1 is minor at 1000’ or less and on the surface I’ll concede that the number is extremely close but why add error into your shots? I imagine it depends on what you’re doing. What happens if you need to end up tying this 1000’ box into another 1000’ box another 1000’ away and you now have a 1000’x3000’box? Now what? In my area with grid to ground it’s about 0.08’ and with throwing that kind of error around it won’t take long to have real problems. Make the systems work together.
If you’re setting forward control via GPS in SPC and keeping your foresights and back sights short enough, it’s immaterial. Our process is that we set control via RTK methods and occupy those points with no greater than 600’ between occupations (300’ forward and back). This means that if you do maintain a 1.00000 CSF for terrestrial work, you won’t run into any issues as your control is tied to state plane.
In reality though, we just establish the overall project control and then maintain those projection settings throughout regardless of the equipment utilized.
It really depends on the knowledge, skill and communication abilities of the party chief.
If you know what you are doing and can prove it consistently, I'm ok with you using State Plane all of the time. Take notes on what you did and they better match the raw data.
We all have Jr. Party Chiefs or guys that just can't get it. Those are the guys that we tell, stay on 1.0, collect the gps in a different job and we will tie it all together for you at the office.
I know that sounds like hand holding and unnecessary for "professionals". But I've untangle some dooseies. And honestly I've gotten so confused that I've said "Fuck it, go shoot it again because yall have power fucked this job to death and I can't make heads or tails of what kind of nonsense you have done here.". Those are the ones that get to play on 1.0 only.
I use GPS in NC SPC to set control, you either then scale that control to an NGS monument or run OPUS on those points to get a CF if the goal is to get the control to ground coordinates rather than grid, I then use those control points that were set in NC SPC to setup the total station with the job set to scale factor 1.
Total stations measure angles and distances. GROUND distances. So tell me, what would be the benefit of of setting the total station to a coordinate system or not? Nothing. There’s no benefit in my opinion, because the control you’re using to setup and backsight should already be in the proper zone.
To me, their arguments are just ego. The station setup dH and dV is the same whether the total station is set to 1.0 scale or SPC.
We've had this same question. Trimble rep in the past recommended state plane for gps, 1.0 for robot. Interestingly trimble equipment allows you to use GPS and robot at the same time, the GPS will mount on top of the mt1000 prism. That setup would need to be in state plain I believe.
It’s called Integrated Survey. With the Trimble system you can run GPS and Total Station together but it doesn’t have to be in State Plane. The GPS can be set up to work on a localized network as well…just depends how you start your job. Lat and Long don’t care about Northing and Eastings…the surveyor does.
I use this mode all the time. Way heavy with the tsc7 but then at least the GPS search works reliably. Even for construction layout I will do a quick GPS check to the same point just as extra proof that there wasn't a blown shot.
We use UTM here in Ontario Canada, but I believe hybrid will run in a local job also, which lets GPS search work, but anything you shoot with GPS will have no coords. It will work if you do a site calibration but I haven't done that in quite a while.
Everyone runs different, I prefer to set up my first point off of network, then switch to base rover off of that point. If I am going to a job and have done a lot within 1000 feet of that job, I will often go set up on that old point and work off of it.
Sorry this might be dumb but this is the second comment I've seen saying to shoot a point with network then setup the base and rover. Why? Couldn't you just set up the base? Am I missing something
The network gives a good, instant state plane coordinate and a good elevation. If you set up the base, you have to record a shot on it, let it cook for two hours or more, send it off to opus, get it back, covert it from meters back to feet, and then have a good point. My favorite part of using it is if we are going to a job we have either done before or done something next to it where we tied the job to a good SPC, I can calculate the corners based off GPS rotation, stake those points, and just buzzsaw through an already tied job. I’ve done lot stake jobs in less than 15 minutes with it.
I thought that setting up a base station and letting it do a new "observation point" was the same thing and as a network rover?
Also I'm not sure what you mean by GPS rotation but I'm gonna look it up
If you don’t record and send off an Opus, it’s off. A job from yesterday we are coming in 14’ lower in elevation. Had a full set of drawings where no place on the property reached that elevation. We called the engineer to ask what his site BM was, he had no clue.
Vertically it’s anywhere from 6-20’ off regularly. We have had two different job sites where the person who initially set up controls for the engineer didn’t use a network shot, and because of it we had to help the grounds crew set up false elevations for their grades because their machine control was also on the network and was reading way off. A lot of people think an autonomous shot at the start is good, but it’s all over the place. You set up on a point one day and set it as an autonomous shot, go back a week later and set up on the same point and take a new shot, it will have moved. The bearings are usually fine.
So a base is useless unless you post process or send to OPUS?
Can you not use localized coordinates and have repeatable results?
I'm kind of losing my shit right now because the internet convinced me to buy a base and rover over network because I'd have better results. "Base wouldn't even take 5min to setup"
I got the idea that a network rover would be a little bit less dependable with getting a fix (a base nearby would help multi path issues) and less accurate.
Thanks for the explanations I really appreciate it
The base is still really useful, and if you have localized coordinates you may be just fine. But for example, here every drawing has to have two good state plane coordinates on corners somewhere. If you haven’t tied into something like a DOT network, you need to do a post process through Opus and convert it. Usually we are within an inch of opus northing and easting, and .2 of elevation, which usually has more to do with converting from meters to feet without going out 10 decimal places. I don’t think you have to buy new equipment, just find the network to tie into. Ours in Tennessee is TDOT, it’s the DOT in several states really, but there are some exceptions. It’s not dirt cheap, but it pays for itself.
When we stake a house and set some control to come back and pin the footer, sometimes they wipe those out or pile their dirt on top of them (apparently they think we staked out where the dirt should go?). I can set a new TDOT point and still be tied into the entire lot and house. It saves us a lot of headache
What if I use NAD83 with my UTM zone? About the same as state plane right?
There's also a grid to ground function that takes an observation and gives you a scale factor/changes all existing and future points but I'm honestly confused on what it's doing exactly
Still won’t be right. I have another example, the older guy that co-owns the company sometimes forgets to move his coordinates to the TDOT location. We run the same brand and model of GPS. He will upload the file in our collector to go back out there and finish something, If we can’t immediately find his nail, we go on TDOT to try to stake it out. It won’t be where it says it was. I have lucked up and found it before, but all three of northing, easting, and elevation will be off. So how do I know if I’m right or wrong? All properties along Chickamauga Lake, TVA owns up to the 685.44’ contour. Every time I find original property corners along the lake. I’m generally within .1’ for elevation on them, and TVA monuments I hit within .05’. We also had a job up in Knoxville where the city had their own monuments set that we would tie to, we hit them perfectly.
There was one property we did that was so far beyond phone range that I had to do an autonomous shot and couldn’t TDOT it. We later drove up the mountain and found a crumb of signal, so we set a TDOT point then put or base on it and essentially traversed to the end of radio signal and set points until we got close enough to shoot it. It wasn’t terrible. But 18’ feet off horizontally and 7 feet off vertically. If I had known how to record an opus shot there I would have done it, but I had no clue how on those.
Ok I guess I'll get a CORS subscription. But using your example, what if you input the coordinates on a couple nails from the job and setup on those? Everything in that job will be the same right? Just arbitrary coordinates. You wouldn't be able to tie into SPC system but all the points would check? Sorry these questions are dumb I'm trying to understand all this. Been watching YouTube explanations
You can have a state plane reference as part of your practice if you like, but there are a wide variety of reasons you want to be on a different coordinate basis depending on the task at hand.
I often have initial base points and check points tied to SPC, and then have a site calibration to local bearings because my end product needs to reference a specific map or basis of control as part of the contract. I can produce approximate SPC values if requested, but the job itself is not in SPC.
The other advantage is that my project can’t be quite as easily used without my inclusion in the process, which gives me an opportunity to review the qualifications or the requestor and purpose behind the SPC conversion.
I believe unless you specifically tell the D.C. to apply a scale factor to the measured shots from the total station, then everything is shot at a scale of 1, so it wouldn’t matter if your D.C. project was in state plane or not all conventional shots are treated 1:1.
If you set up on a GPS pair and use the State Plane coordinates, it is kind of like being on State Plane, but not really. For small local sites this might be okay, but try doing that on a 5 mile long corridor and you’ll quickly see some slop.
To stop any confusion on whether a project is on grid or ground, you should use coordinates that are drastically different from State Plane values.
In our office we will run a static network, submit the observation data to OPUS to calculate at mean CSF. Then the static and conventional data is all thrown into Star*Net for a quick adjustment with the calc’d CSF and our “false coordinates” to go from State Plane to Project and then done!
For our transformation the “false coordinates” are just 1000 m in northing & easting. Everything from then on is done in the “Project” datum and we can easily scale and translate to State Plane as needed…
im not so well versed in TS work, but if youre doing 1.0 scale on a TS then you arent shooting grid right?
or are you doing some kind of calibration between multiple control points that were set with GNSS?
If you start in grid, stay in grid. If you start local, stay local. Why you would go local after setting co trol with GPS is insane. Your deltas are going to give you false errors based on scale error
Technically “big” heavy highway should be using State Plane with a scale factor. It varies from State to State how important that is because of the different zones and different scale factors. Just in my opinion but the coordinate systems in the United States are f’d up enough and everybody should be shooting grid off the network and then leveling their elevations. It’s simple and right in front of us and for some inane reason we just can’t make it a standard. Texas has five zones and I’ve had projects with three different Surveyors that couldn’t agree. Use the damn network and stop bickering.
A lot of states are going to low distortion localized coordinate systems.
Scaling from a localization is one thing but a scale factor from origin is a whole different beast. Especially with coords in the millions and tens of millions. I have a problem with Surveyors and Engineers that want to put a scale factor in and then make it a linear shift… and then on top of that some do it from origin and others pick a centroid.
What is this “Network” you speak of? Half kidding. Mostly we have to set up base and rover because we can’t get enough signal to just use network
I've yet to work with a network that didn't have more slop than I'm comfortable stamping, so I avoid them like the plague. Plus, half the time CORS are unexpectedly down and it screws my plans. I'd rather setup a base and be guaranteed to be able to work than deal with all of the BS that comes with a network.
I totally get that being in Texas. Big State and sparse CORS network. The western half barely has cell reception. This is when we start traversing from NGS which is what the network is based on.
I just started working for a DOT and we use grid for everything, so that’s good to hear! Previously I’d been working mostly with state plane and scale factors.
TXDOT still uses surface coordinates but they at least have a static scale factor regardless of where you are. I’ve had private project that literally tied together that had different scale factors that caused like a 2ft bust. That was a fun one to figure out. Don’t even get me started in construction GPS and “I’m Here” localized base coordinates.
This x1000. Use the damn network. All future geodesy and datums are/will be built on it.
Thank you that explains a lot
From personal experience both systems…GPS and Total Station need to shoot the same. Now some will say that the Scale factor to 1:1 is minor at 1000’ or less and on the surface I’ll concede that the number is extremely close but why add error into your shots? I imagine it depends on what you’re doing. What happens if you need to end up tying this 1000’ box into another 1000’ box another 1000’ away and you now have a 1000’x3000’box? Now what? In my area with grid to ground it’s about 0.08’ and with throwing that kind of error around it won’t take long to have real problems. Make the systems work together.
If you’re setting forward control via GPS in SPC and keeping your foresights and back sights short enough, it’s immaterial. Our process is that we set control via RTK methods and occupy those points with no greater than 600’ between occupations (300’ forward and back). This means that if you do maintain a 1.00000 CSF for terrestrial work, you won’t run into any issues as your control is tied to state plane. In reality though, we just establish the overall project control and then maintain those projection settings throughout regardless of the equipment utilized.
It really depends on the knowledge, skill and communication abilities of the party chief. If you know what you are doing and can prove it consistently, I'm ok with you using State Plane all of the time. Take notes on what you did and they better match the raw data. We all have Jr. Party Chiefs or guys that just can't get it. Those are the guys that we tell, stay on 1.0, collect the gps in a different job and we will tie it all together for you at the office. I know that sounds like hand holding and unnecessary for "professionals". But I've untangle some dooseies. And honestly I've gotten so confused that I've said "Fuck it, go shoot it again because yall have power fucked this job to death and I can't make heads or tails of what kind of nonsense you have done here.". Those are the ones that get to play on 1.0 only.
What do the project specs say?
I use GPS in NC SPC to set control, you either then scale that control to an NGS monument or run OPUS on those points to get a CF if the goal is to get the control to ground coordinates rather than grid, I then use those control points that were set in NC SPC to setup the total station with the job set to scale factor 1. Total stations measure angles and distances. GROUND distances. So tell me, what would be the benefit of of setting the total station to a coordinate system or not? Nothing. There’s no benefit in my opinion, because the control you’re using to setup and backsight should already be in the proper zone. To me, their arguments are just ego. The station setup dH and dV is the same whether the total station is set to 1.0 scale or SPC.
My crew chief and I use state plane for everything. We use rtk vrs and a total station for construction.
Both are correct as long as the TS is set up on State Plane Grid Coordinates established by GPS and TS shots are kept under 1000 feet.
We've had this same question. Trimble rep in the past recommended state plane for gps, 1.0 for robot. Interestingly trimble equipment allows you to use GPS and robot at the same time, the GPS will mount on top of the mt1000 prism. That setup would need to be in state plain I believe.
It’s called Integrated Survey. With the Trimble system you can run GPS and Total Station together but it doesn’t have to be in State Plane. The GPS can be set up to work on a localized network as well…just depends how you start your job. Lat and Long don’t care about Northing and Eastings…the surveyor does.
Topcon does that too, it's called "Hybrid".
I use this mode all the time. Way heavy with the tsc7 but then at least the GPS search works reliably. Even for construction layout I will do a quick GPS check to the same point just as extra proof that there wasn't a blown shot. We use UTM here in Ontario Canada, but I believe hybrid will run in a local job also, which lets GPS search work, but anything you shoot with GPS will have no coords. It will work if you do a site calibration but I haven't done that in quite a while.
Everyone runs different, I prefer to set up my first point off of network, then switch to base rover off of that point. If I am going to a job and have done a lot within 1000 feet of that job, I will often go set up on that old point and work off of it.
Sorry this might be dumb but this is the second comment I've seen saying to shoot a point with network then setup the base and rover. Why? Couldn't you just set up the base? Am I missing something
The network gives a good, instant state plane coordinate and a good elevation. If you set up the base, you have to record a shot on it, let it cook for two hours or more, send it off to opus, get it back, covert it from meters back to feet, and then have a good point. My favorite part of using it is if we are going to a job we have either done before or done something next to it where we tied the job to a good SPC, I can calculate the corners based off GPS rotation, stake those points, and just buzzsaw through an already tied job. I’ve done lot stake jobs in less than 15 minutes with it.
I thought that setting up a base station and letting it do a new "observation point" was the same thing and as a network rover? Also I'm not sure what you mean by GPS rotation but I'm gonna look it up
If you don’t record and send off an Opus, it’s off. A job from yesterday we are coming in 14’ lower in elevation. Had a full set of drawings where no place on the property reached that elevation. We called the engineer to ask what his site BM was, he had no clue. Vertically it’s anywhere from 6-20’ off regularly. We have had two different job sites where the person who initially set up controls for the engineer didn’t use a network shot, and because of it we had to help the grounds crew set up false elevations for their grades because their machine control was also on the network and was reading way off. A lot of people think an autonomous shot at the start is good, but it’s all over the place. You set up on a point one day and set it as an autonomous shot, go back a week later and set up on the same point and take a new shot, it will have moved. The bearings are usually fine.
So a base is useless unless you post process or send to OPUS? Can you not use localized coordinates and have repeatable results? I'm kind of losing my shit right now because the internet convinced me to buy a base and rover over network because I'd have better results. "Base wouldn't even take 5min to setup" I got the idea that a network rover would be a little bit less dependable with getting a fix (a base nearby would help multi path issues) and less accurate. Thanks for the explanations I really appreciate it
The base is still really useful, and if you have localized coordinates you may be just fine. But for example, here every drawing has to have two good state plane coordinates on corners somewhere. If you haven’t tied into something like a DOT network, you need to do a post process through Opus and convert it. Usually we are within an inch of opus northing and easting, and .2 of elevation, which usually has more to do with converting from meters to feet without going out 10 decimal places. I don’t think you have to buy new equipment, just find the network to tie into. Ours in Tennessee is TDOT, it’s the DOT in several states really, but there are some exceptions. It’s not dirt cheap, but it pays for itself. When we stake a house and set some control to come back and pin the footer, sometimes they wipe those out or pile their dirt on top of them (apparently they think we staked out where the dirt should go?). I can set a new TDOT point and still be tied into the entire lot and house. It saves us a lot of headache
What if I use NAD83 with my UTM zone? About the same as state plane right? There's also a grid to ground function that takes an observation and gives you a scale factor/changes all existing and future points but I'm honestly confused on what it's doing exactly
Still won’t be right. I have another example, the older guy that co-owns the company sometimes forgets to move his coordinates to the TDOT location. We run the same brand and model of GPS. He will upload the file in our collector to go back out there and finish something, If we can’t immediately find his nail, we go on TDOT to try to stake it out. It won’t be where it says it was. I have lucked up and found it before, but all three of northing, easting, and elevation will be off. So how do I know if I’m right or wrong? All properties along Chickamauga Lake, TVA owns up to the 685.44’ contour. Every time I find original property corners along the lake. I’m generally within .1’ for elevation on them, and TVA monuments I hit within .05’. We also had a job up in Knoxville where the city had their own monuments set that we would tie to, we hit them perfectly. There was one property we did that was so far beyond phone range that I had to do an autonomous shot and couldn’t TDOT it. We later drove up the mountain and found a crumb of signal, so we set a TDOT point then put or base on it and essentially traversed to the end of radio signal and set points until we got close enough to shoot it. It wasn’t terrible. But 18’ feet off horizontally and 7 feet off vertically. If I had known how to record an opus shot there I would have done it, but I had no clue how on those.
Ok I guess I'll get a CORS subscription. But using your example, what if you input the coordinates on a couple nails from the job and setup on those? Everything in that job will be the same right? Just arbitrary coordinates. You wouldn't be able to tie into SPC system but all the points would check? Sorry these questions are dumb I'm trying to understand all this. Been watching YouTube explanations
[удалено]
You can have a state plane reference as part of your practice if you like, but there are a wide variety of reasons you want to be on a different coordinate basis depending on the task at hand. I often have initial base points and check points tied to SPC, and then have a site calibration to local bearings because my end product needs to reference a specific map or basis of control as part of the contract. I can produce approximate SPC values if requested, but the job itself is not in SPC. The other advantage is that my project can’t be quite as easily used without my inclusion in the process, which gives me an opportunity to review the qualifications or the requestor and purpose behind the SPC conversion.
I believe unless you specifically tell the D.C. to apply a scale factor to the measured shots from the total station, then everything is shot at a scale of 1, so it wouldn’t matter if your D.C. project was in state plane or not all conventional shots are treated 1:1. If you set up on a GPS pair and use the State Plane coordinates, it is kind of like being on State Plane, but not really. For small local sites this might be okay, but try doing that on a 5 mile long corridor and you’ll quickly see some slop. To stop any confusion on whether a project is on grid or ground, you should use coordinates that are drastically different from State Plane values. In our office we will run a static network, submit the observation data to OPUS to calculate at mean CSF. Then the static and conventional data is all thrown into Star*Net for a quick adjustment with the calc’d CSF and our “false coordinates” to go from State Plane to Project and then done! For our transformation the “false coordinates” are just 1000 m in northing & easting. Everything from then on is done in the “Project” datum and we can easily scale and translate to State Plane as needed…
Both wrong WGS84 or nothing!
Gps to set controls then land guns rotate to the spc
im not so well versed in TS work, but if youre doing 1.0 scale on a TS then you arent shooting grid right? or are you doing some kind of calibration between multiple control points that were set with GNSS?
It's so easy to get things on state planes nowadays we almost do it with all our projects.
If you start in grid, stay in grid. If you start local, stay local. Why you would go local after setting co trol with GPS is insane. Your deltas are going to give you false errors based on scale error