Don't even get me started on vertical datums and RTNs...
RTN's broadcast ellipsoidal height. It does not deal with vertical datums. The user controls how local observations are tied to their chosen vertical datum. I've seen notes on surveys that the vertical datum is the RTN. That is a meaningless note other than it lets me know they used whatever elev. came out of their field software based on the software settings.?ÿ
Don't even get me started on vertical datums and RTNs...
RTN's broadcast ellipsoidal height. It does not deal with vertical datums. The user controls how local observations are tied to their chosen vertical datum. I've seen notes on surveys that the vertical datum is the RTN. That is a meaningless note other than it lets me know they used whatever elev. came out of their field software based on the software settings.?ÿ
This is the future. From NGS:
(bold is mine for ephasis)
?ÿ
To improve the National Spatial Reference System (NSRS), NGS will replace all three North American Datum of 1983 (NAD 83) frames and all vertical datums, including the North American Vertical Datum of 1988 (NAVD 88), with four new terrestrial reference frames and a geopotential datum.
The new reference frames will rely primarily on Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), as well as on a gravimetric geoid model resulting from our Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project.
These new reference frames will be easier to access and to maintain than the current NSRS, which relies on physical survey marks that deteriorate over time.
Don't even get me started on vertical datums and RTNs...
RTN's broadcast ellipsoidal height. It does not deal with vertical datums. The user controls how local observations are tied to their chosen vertical datum. I've seen notes on surveys that the vertical datum is the RTN. That is a meaningless note other than it lets me know they used whatever elev. came out of their field software based on the software settings.?ÿ
This is the future. From NGS:
(bold is mine for ephasis)
?ÿ
To improve the National Spatial Reference System (NSRS), NGS will replace all three North American Datum of 1983 (NAD 83) frames and all vertical datums, including the North American Vertical Datum of 1988 (NAVD 88), with four new terrestrial reference frames and a geopotential datum.
The new reference frames will rely primarily on Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), as well as on a gravimetric geoid model resulting from our Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project.
These new reference frames will be easier to access and to maintain than the current NSRS, which relies on physical survey marks that deteriorate over time.
?ÿ
Translation: I am grateful to all those that work on and partner with WSRN!?ÿDon't even get me started on vertical datums and RTNs...
RTN's broadcast ellipsoidal height. It does not deal with vertical datums. The user controls how local observations are tied to their chosen vertical datum. I've seen notes on surveys that the vertical datum is the RTN. That is a meaningless note other than it lets me know they used whatever elev. came out of their field software based on the software settings.?ÿ
This is the future. From NGS:
(bold is mine for ephasis)
?ÿ
To improve the National Spatial Reference System (NSRS), NGS will replace all three North American Datum of 1983 (NAD 83) frames and all vertical datums, including the North American Vertical Datum of 1988 (NAVD 88), with four new terrestrial reference frames and a geopotential datum.
The new reference frames will rely primarily on Global Navigation Satellite Systems (GNSS), such as the Global Positioning System (GPS), as well as on a gravimetric geoid model resulting from our Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project.
These new reference frames will be easier to access and to maintain than the current NSRS, which relies on physical survey marks that deteriorate over time.
?ÿ
I for one am looking forward to a national datum aligned with ITRF and a gravimetric geoid-defined national vertical datum.
I'm less enthusiastic about all the local government entities that are going to insist that we still use their "control points" and "benchmarks", which are already outdated as of ten years ago.
My local city uses not NAD83(2011), not NAD83(1998), but NAD83(1991) for its horizontal marks. Two realizations back and over 30 years old. The vertical is slightly better but not by much, and I'm not sure they have good ellipsoid heights on BMs either, so making the change might be more difficult than they realize.
I shouldn't complain too much, because that change - plus the switch to international feet - is going to give me tons of job security. It's going to be messy and frustrating for a lot of folks, though. Surveyors included.
Not going to lie, I'm going to feel a bit of schadenfreude when it happens.
@rover83?ÿ
We had made the shift to Intl Ft until the newly minted 2 months old License decided that it was a violation of state law and switched us back.
One of several reasons I decided to leave, going backwards is never a good option unless you're at the opening end of a draw or swing bridge.
We had made the shift to Intl Ft until the newly minted 2 months old License decided that it was a violation of state law and switched us back.
I'm not sure which state you were in, but in ?ñ44 states the US foot is still the one in use, frequently by statute and, if not, by custom. It is the one that NGS and state agency data sheets will use for the time being.?ÿ When the new datum rolls out it will be in Int'l feet and that will be the appropriate time to make a switch.?ÿ?ÿ
New Mexico,
And we were working along side the NGS and submitted our proposal that was accepted to assist and promote the whole NGS2022 update initiative, with support from NGS and The state of New Mexico, et al
waiting to do it at the end isn't going to work, but I'm just a cog in the machine, trying to figure out how I'll continue with the process of getting to the license, a squeaky noisy one to be sure.
?ÿ
Just out of curiosity I post processed 4 hours of rinex files from the CORS reference stations at Sioux Falls and Pierre SD using the Iowa RTN on line post processing service. Didn't miss either published NGS CORS coordinate by more than 0.02 ft. in N and E. Sioux Falls is in the IaRTN network. Based on that I'd say you could also use the IaRTN post processing in SE SD. You have to register free to use it. Also you could you the real time service within 20 miles of Sioux Falls. I've checked into NGS marks very well 30 miles outside the network in real time.?ÿ https://iowadot.gov/rtn
Notice 2022 in the name, think it will happen this year? Next year? Year after??ÿ
When do you think FEMA maps will shift?
Remember they are political.?ÿ
The old data will be here a looonnnngggggg time.?ÿ
It's going to be a time of keeping old records for projects, slowing shifting to the new data.?ÿ
You start control for a DOT job in 2018 it gets mapped some years later, designed in 2021, money appears in 2025, they decide to put it up for bid in 2026 and build schedule is to begin in 2027 and you have two seasons to finish in 2028.?ÿ
Sound familiar?
Same thing for schools, sewers, streets, roads, bridges, mines, solar sites, windmills..........
No need to get in a hurry.?ÿ
A project is built on the same coordinate system that it begins on. We've already seen RTN's realize new coordinates on their reference stations several times since they started. There are several ways to manage this and still utilize the RTN for current work on the old system if that is easier than simply running a base on the project control. The main thing is to have stable geodetic control on long lasting projects and relate the current RTN observations to those monuments before and after working on it. Many have found it easier to use the RTN to establish control and thereafter use a local monument for a base. It's been my experience that a good field software will allow updating a base point such that the user can assign an old coordinate to a local RTN base station to continue work on the old system. DOT's should publish the coordinate used to start the project on the local RTN base station in the project plans. Operative word I agree is SHOULD.?ÿ
DOT's should publish the coordinate used to start the project on the local RTN base station in the project plans. Operative word I agree is SHOULD.?ÿ
"BuT CoOrDINAteS ArE InfERiOr tO MoNuMENtS!!!111!!!!"
(yes that was sarcasm)
These days, if a controlling entity is not publishing geodetic values,?ÿ reference frame, epoch, projection parameters, project datum parameters, project datum values, and transformation values on their plansets, they're just negligent.
Do it right or don't do it at all.
Don't do it at all.?ÿ I listened when the First Lady told us all to "Just say no."
