I attended the NGS Geospatial Summit in Silver Spring the last two days. The main focus of the gathering was the upcoming changes to new horizontal reference frames and vertical datum in 2022. Here are my recollections of what was presented...
HORIZONTAL: There will be four new horizontal reference frames:
North American Terrestrial Reference Frame of 2022 (NATRF2022, pronounced natref 2022)
Pacific Terrestrial Reference Frame of 2022 (PTRF2022)
Mariana Terrestrial Reference Frame of 2022 (MTRF2022)
Caribbean Terrestrial Reference Frame of 2022 (CTRF2022)
All four will be based on ITRFxx (whatever the most recent xx is at the time) at a fixed epoch (possibly/probably 2020.00). The NATREF2022 will remain fixed to that epoch (until someone decides it has drifted too far away from current ITRF). There are slight rotations remaining on the fixed portion of the north american plate, those will be used to convert ITRFxx epoch XXXX.xx to NATREF2022 epoch 2020.00(?). Similar situation for the other three reference frames. There were some concerns raised by non-NGS people that maybe we should be going totally dynamic (i.e. not a fixed epoch). I imagine that NGS got a lot of feedback prior to making the decision from both sides (dynamic versus static). As we all know, most surveyors do NOT like coordinates that are constantly changing. I believe we can have it both ways, because there are accurate velocity models that enable one to convert back and forth. Of particular significance to me was an offhand comment that the new reference frames are NOT a re-adjustment in the sense that all of the passive control will not be dealt with at all. The CORS will be re-processed, and those "new" coordinates will define the frames. If you want to use passive control, you will need to apply a transformation to bring the NAD83 (2011) coordinates up to NATREF2022. At least that is the way I understood it.
BLUEBOOKING: They are working on making OPUS-Projects the way to bring user supplied data into the NSRS database (currently called bluebooking). It was not clear to me whether user processed data (i.e. processed in Trimble TBC, Leica, Topcon, etc) will still be able to be submitted. Someone on the webinar (remote viewer) did specifically ask the question about TBC, but the answer was not clear (in my opinion). To me, this is a major issue. Not all GPS needs to be observed for 2 or 4 hours or more (as is required in OPUS-Projects). I currently have a client who is observing about 20 or 30 new points to be bluebooked in a county, the baselines are short, and 60 minute observations are sufficient (processed in TBC). The data will be adjusted in ADJUST (NGS program), but I do not see the necessity for requiring all data to be processed in OPUS.
VERTICAL: The new vertical datum will be called North American-Pacific Geopotential Datum of 2022 (NAPGD2022). I didn't hear anyone pronounce that, maybe it will be NAPGID? This will be based SOLELY on a geoid model (GEOID2022) and ellipsoidal heights from the above terrestrial reference frames. No benchmarks, no leveling, no hybrid geoid. Accuracy of around 1.4 cm (?). I got that number from 1 cm ellipsoidal heights and a 1 cm geoid model (sqrt (1^2+1^2)). Of course we can still use leveling, but running between two passive marks will probably be way more accurate than the elevations on the marks, so to me that presents a problem. I am not at all clear on what will happen to bluebook leveling, I don't see a fit for that in the new datum.
As someone who does a LOT of both GPS and leveling bluebooking (observed by us and by others, where I just do the processing and submittal), this leaves some unanswered questions. I have been telling people that one advantage of bluebooking is that it gets the data into the NSRS, and whenever there is a re-adjustment (NAD83 (2007), NAD83 (2011), etc) or a new datum (NAD27 to NAD83) then the data will automatically be re-adjusted by NGS. Looks like that may not be the case.
The fact is that 5 years is NOT a long way off, so it is important to educate surveyors about what exactly this means for our future. There will be more summits, webinars, outreach, etc from NGS and others.
If any of my above recollections or assumptions are incorrect, feel free to correct me. Hopefully this will start a productive discussion......
Thanks for the synopsis.
Thanks...that saved me 12 unbillable hours and having to deal with the mass transit crap-shoot that is known locally as "The Red Line"
James Fleming, post: 425476, member: 136 wrote: Thanks...that saved me 12 unbillable hours and having to deal with the mass transit crap-shoot that is known locally as "The Red Line"
Jim: I remember when Silver Spring was a cheap place to stay. Not anymore.
Oh boy!!! Life could get really interesting. I don't see this being easily meshed into existing regulated data, but we will see. From what I've read we will get an adjustment of about -2 feet locally, placing 2020 elevations a tad higher than NGVD29.
Thank you for the summary, John. I attended the almost 2 day session remotely and thought it was well organized and well run regarding keeping speakers on time. I thought it was very valuable to have presentations by folks from outside of NGS (the first day was almost exclusively NGS with the exception of Dave Doyle presenting on behalf of the NSPS) including other Federal agencies (partners), consulting firms, software developers (ESRI, Trimble, etc.) and local government agencies. All of those presenters used the same format for their slides, which provided nice continuity for comparing and contrasting what they shared.
Although it was clear that passive marks will never again be included in any sort of NGS readjustment or realization of the NSRS (about 80,000 were included in the NAD83(2011)2010.00 realization) that doesn't mean that they will no longer be accepted into the NSRS via the Bluebook process or the successor thereto. Although transformation tools will be provided (NADCON5) to move passive positions to the new reference frame (NATRF2022), which will be acceptable for some applications, the more accurate solution will be to reprocess the original data in the new reference frame, or to reobserve the marks.
It seems that NGS is committed to expanding OPUS Projects (OP) to include leveling and traverse data and some of this was shown during the presentations. I surmise that will provide the ability to submit terrestrial observation data through OP for inclusion in the NSRS. The current Integrated Database (IDB) will be replaced by a much more robust geospatial database, as will datasheets be greatly improved. The ability to extract and analyze historical data on marks that have been submitted multiple times will be greatly enhanced over the confusing "mess" it is now.
Working on the west coast of CONUS, which is not on the North American plate, we continually deal with dynamic conditions relative to the reference frame and that will remain the case with NATRF2022. It is not clear that NGS is committed to continuing the update and support of HTDP post 2022, but they do recognize that some sort of 2D or 3D positional modeling tool through time (thus 4D) will still be needed by those working in the "deformation areas" with regards to the reference frame.
As John said, 5 years is not long when getting prepared to transition to an entirely new system. It was encouraging to see that NGS is bringing everyone to the table to be involved, recognizing the magnitude of what a couple presenters referred to as an "unfunded mandate."
The entire program was recorded and likely will be posted within a few weeks. Here is the detailed agenda so folks have an idea of who presented.
https://www.ngs.noaa.gov/geospatial-summit/detailed-agenda.pdf
Yes, they did say that OPUS-Projects will have leveling, traverse, etc tabs. Not sure how exactly that will reside in to DB if they are not adjusting passive marks. One possibility is that they will provide an "on-the-fly" transformation so that a data sheet for a passive mark can be created with the NATREF2022 coordinates (via transformation) from the NAD83 (2011) coordinates. But, will new BB submittals be in the database as NATREF2022 only?
Looking forward to the new database for sure.
With respect to the new vertical datum, as the designation GEOID### is used for hybrid models, won't it be either USGG or a new designation for the gravimetric geoid?
The hybrid models, incorporating data transformations, corrector surfaces and the like, have improved (especially with the GPS on BM campaigns) over the years but the level network they intend to approximate is not maintained, undergoing large losses, and has some inherent problems e.g. The cross-continental tilt. The gravimetric models are not distorted to fit the NAVD88 network. As they are based in the ITRF frame there is no need to deal with the transformations.
As for the vertical blue-booking within the OPUS-Projects paradigm, I do not see enough resources going to this effort. As a remote attendee (one of the six) to the OPUS-Projects webinar, comments made there make me think that they have not looked deeply enough into the problem. Good quality geodetic leveling and the adjustment (to what?) is harder than most horizontal/GPS folks realize. As Dr Schenewerk mentioned, he is an astronomer. His work with GNSS has many links to astronomy. No knock on him but leveling is far removed. Except of course Astro-geodetic leveling. But I digress.
If it were easy why is there the cross country tilt in NAVD88 and many remaining unknown biases.
Sorry I was unable to attend. Listening was unfortunately not an option either.
GeeOddMike, post: 425525, member: 677 wrote: With respect to the new vertical datum, as the designation GEOID### is used for hybrid models, won't it be either USGG or a new designation for the gravimetric geoid?
The hybrid models, incorporating data transformations, corrector surfaces and the like, have improved (especially with the GPS on BM campaigns) over the years but the level network they intend to approximate is not maintained, undergoing large losses, and has some inherent problems e.g. The cross-continental tilt. The gravimetric models are not distorted to fit the NAVD88 network. As they are based in the ITRF frame there is no need to deal with the transformations.
As for the vertical blue-booking within the OPUS-Projects paradigm, I do not see enough resources going to this effort. As a remote attendee (one of the six) to the OPUS-Projects webinar, comments made there make me think that they have not looked deeply enough into the problem. Good quality geodetic leveling and the adjustment (to what?) is harder than most horizontal/GPS folks realize. As Dr Schenewerk mentioned, he is an astronomer. His work with GNSS has many links to astronomy. No knock on him but leveling is far removed. Except of course Astro-geodetic leveling. But I digress.
If it were easy why is there the cross country tilt in NAVD88 and many remaining unknown biases.
Sorry I was unable to attend. Listening was unfortunately not an option either.
GeeOddMike: They said it would be GEOID2022, so I guess that will be the end of the hybrid models.
See the pdf I uploaded...
Thanks for the outline and comments John.
I was registered for the Summit (remote/online), but work/life intervened. I look forward to watching the recorded version.
Although I hope to be [at least] semi-retired by 2022 (but still upright), I have been looking forward to this further evolution of the NSRS for quite some time now.
Personally, I am not a big fan of pseudo-stable (solid plate) Datums, but I DO understand why many folks feel more comfortable with that scenario. Furthermore, many (if not most) parts of CONUS are reasonably adaptable to such a temporal/spatial paradigm.
Obviously the bottom line (static OR dynamic) is dependent on the "accuracy" of the underlying Velocity Model. The HTDP Models have continued to improve over the years, but like all 'models,' there will continue to be uncertainty in those areas where GOOD data points are sparse. For those of us in Western CONUS, the potential loss of the Plate Boundary Observatory (PBO) sites, is of significant concern to us (more so the further West you go).
I guess what I'm trying to get at, is simply that YOU CAN determine WHERE YOU ARE TODAY (relative to say igs08) very easily (and accurately) using OPUS, but to retrodict THAT position 7+ years into the past, is totally a function of your CURRENT Velocity Model. So unless YOU (or someone else) was THERE back on January of 2010, then you can't be absolutely sure of your Epoch 2010.0000 estimate.
My experience West of the Main Ridge of the Rocky Mountains over the years, indicates that HTDP works very well (and gets better with each update), but one must still take the sparse data point coverage out here into consideration.
Loyal
Loyal,
You bring up an excellent point of concern regarding the future status of the PBO sites. We have over 600 of them in California alone, and over 80% of our NGS CORS stations are PBO sites. We are anxiously awaiting news of the National Science Foundation's award of the next science project, the "Network of the Americas" (I believe is the title) and how the winning proposal plans to leverage the PBO CGPS sites and what level of funding will be provided. We will probably know who was selected (UNAVCO/PBO submitted a proposal) by mid to late summer, but may not know the funding levels until early to mid-fall. If we lost 80% of our CORS stations, virtually over night, it would be a disaster.
The addition of these 600+ sites in California, and the data therefrom, have greatly enhanced the accuracy and grid resolution of HTDP in even the most complex faulting areas along the plate boundary (North American and Pacific) here.
John Hamilton, post: 425536, member: 640 wrote: GeeOddMike: They said it would be GEOID2022, so I guess that will be the end of the hybrid models.
See the pdf I uploaded...
Thanks. The PDF does show that after years of naming their hybrid models GEOID and gravimetric models USGG, the new gravimetric model will be labeled GEOID. I guess I am the only one finding that naming convention confusing.
Thanks for the report and follow up.
Cheers,
DMM
Glad to hear the new reference frame will be at a fixed epoch. I had heard as recently as last week that it would be dynamic. It will be nice for NAD and ITRF/WGS84 to be in better agreement.
I was thinking about the dynamic situation last week. A few years back [USER=228]@Loyal[/USER] told me one of the things he likes about his low distortion projections is that the origin can be changed to accommodate changes to the underlying geodetic positions of points while still keeping the grid coordinates unchanged. I was thinking that if we do away with State Plane (which I am in favor of) and move toward county wide LDP's that the projections could be dynamic, allowing the grid coordinates to remain the same (more or less). But it looks like that won't be an issue. I do hope that we move from SPC to LDP regardless.
Mike: lots of confusion ahead...
Shawn Billings, post: 425558, member: 6521 wrote: Glad to hear the new reference frame will be at a fixed epoch. I had heard as recently as last week that it would be dynamic. It will be nice for NAD and ITRF/WGS84 to be in better agreement.
I was thinking about the dynamic situation last week. A few years back [USER=228]@Loyal[/USER] told me one of the things he likes about his low distortion projections is that the origin can be changed to accommodate changes to the underlying geodetic positions of points while still keeping the grid coordinates unchanged. I was thinking that if we do away with State Plane (which I am in favor of) and move toward county wide LDP's that the projections could be dynamic, allowing the grid coordinates to remain the same (more or less). But it looks like that won't be an issue. I do hope that we move from SPC to LDP regardless.
It will be aligned at the beginning, and then drift away. As phones get more accurate GPS, that will be an issue. If a phone GPS can get 0.10 m accuracy, and the two systems are drifting apart at several cm's a year, then it won't be long before the difference becomes noticeable.
Yes, I advocated that each of the 39 deformation projects that we do should have a local coordinate system with an origin at a fixed location (i.e. monumented point) at the site. If that monument gets new global coordinates, no big deal, it won't change the local coordinates. Deformation surveys do not like dynamic coordinate systems! It is hard to measurement local movement when the whole coordinate system is also moving,
Yes, the 48 states that employ a State Plane Coordinate System have decisions to make soon. Oregon implemented LDP's to cover the entire state, which resulted in the creation of 39 zones to comply with their maximum acceptable distortion tolerances. They had two zones in the conventional State Plane Coordinate system using a Lambert Projection. The 39 LDP zones use Lambert, Transverse Mercator, and Oblique Mercator projections (along the coast and rivers). It hurts my head to think about how many it would take to do something similar to cover California. We currently have 6 zones.
Interesting that it was mentioned during the first day of the Summit that Michael Dennis, NGS, will be leading the State Plane Coordinate definition effort as we move towards 2022. Michael was heavily involved in the Oregon LDP project.
ftp://ftp.odot.state.or.us/ORGN/Documents/ocrs_handbook_user_guide.pdf
Even States with LDP systems in place will need to look at some changes. I suspect that Oregon will want to change the Grid North and Grid East of the origin to make the values distinguishable.
It is encouraging that Michael Dennis is leading the SPC definition effort. I do hope NGS takes advantage of this opportunity to advance beyond large area, high distortion projections.
Shawn Billings, post: 425584, member: 6521 wrote: Even States with LDP systems in place will need to look at some changes. I suspect that Oregon will want to change the Grid North and Grid East of the origin to make the values distinguishable.
It is encouraging that Michael Dennis is leading the SPC definition effort. I do hope NGS takes advantage of this opportunity to advance beyond large area, high distortion projections.
I've been involved with LDPs for the State of Alaska (we used Michael Dennis's no-longer-available awesome software). In a discussion on the topic with NGS about 2 1/2 years ago, they seemed to not want to take on definition or custodianship of LDPs, leaving it to states/counties/municipalities. I think that's a pretty good idea, with one exception: I think it would be very cool to be able to pick your coordinate system for OPUS results (maybe OPUS could tap the EPSG database for map projections associated with NAD83/the new 2022 datum)!
Actually, some states are expressing a desire to go to one single zone, which much higher scale factors. Better for statewide GIS, not so good for surveyors doing highway layout, etc.
John Hamilton, post: 425592, member: 640 wrote: Actually, some states are expressing a desire to go to one single zone, which much higher scale factors. Better for statewide GIS, not so good for surveyors doing highway layout, etc.
Some have gone beyond a desire. Take Montana and its SPC NAD83 single zone.
Projection: Lambert Conformal Conic (2 parallel)
Northern Parallel: 49å¡ 00' 00" N
Southern Parallel: 45å¡ 00' 00" N
Origin Latitude: 44å¡ 15' 00" N
Origin Longitude: 109å¡ 30' 00" W
False Easting: 0.00 m
False Northing: 6,000,000.00 m
Units: Meters
Datum: NAD83
The Standard Parallels lie on the Wyoming and Canada borders.
For places along the 47th Parallel like Misoula, Lewiston and Glendive the grid scale factor approaches 0.999393
