You may have heard about the uproar caused by the media in Australia because of their decision to go with a dynamic datum. Well, it will probably happen (in one way or another) here as well in 2022, and we as surveyors all need to be aware of the possibility, and what it means. NGS is undertaking an education role, so hopefully by the time the new datum gets here we will all be prepared.
http://www.spatialsource.com.au/2016/08/australia-move-geodetic-surveyors-dispel-confusion/
I blame modern politics. The flat earth society is still taking members! (make joke!)
I guess for me, (a sort of young earth, creationist) the idea that things are not moving MORE and FASTER is probably more fascinating. We are seeing a merging of Land Surveying with Geodesy. This is one of the better arguments for the 4 yr college requirement. It will be darn near impossible to "keep up" with our coordinates, if we don't "Know where they went".
Probably a better way to say it, is that "To be a truly professional surveyor, in the most professional sense, is going to have to include modern geodesy".
As I face this issue, I have been thinking of 2 things. I live far from any CORS sites. An OPUS or a DPOS solution has more than average error here, due to the long distance to my CORS sites. I am thinking about installing my own permanent GPS site, to strengthen the DOPS solutions in my area. (I'm in a low density population area... I do not mean to imply that folks are not dense here too, but that that there is not alot of people per square mile!) Ha!
Surveying is sure a developing profession. I think it is one of the funnest days to be alive.
As price drops, and CORS stations become more populous, time marches on. I have been thinking about all the stuff it takes to be a surveyor today. What does a properly equipped Surveyor look like?
Nate
One idea I have is to create coordinate systems on maybe a county level. There would be a CORS in the middle of the county, and while its geodetic coordinates would be dynamic, it could be the origin of a local grid coordinate system. The origin lat/long would be constantly (albeit very slowly) changing, but the grid coordinates would remain practically unchanged (unless you happen to have a fault line running through the county). Any vectors from the origin CORS could be used to directly compute the local coordinates.
FWIW, the issue of adopting an ITRF-based datum in the US was discussed by the US NGS back in 1997. See this report: http://www.ngs.noaa.gov/NationalReadjustment/Items/PAT14report.html
For me, the shift from relative positioning wrt ground-based control to precise positioning directly from GNSS is the direction to which we are still migrating. While I have not kept up with the most recent developments, I was impressed with the precise-point positioning tools available a few years ago.
Cheers,
DMM
John Hamilton, post: 386741, member: 640 wrote: One idea I have is to create coordinate systems on maybe a county level. There would be a CORS in the middle of the county, and while its geodetic coordinates would be dynamic, it could be the origin of a local grid coordinate system. The origin lat/long would be constantly (albeit very slowly) changing, but the grid coordinates would remain practically unchanged (unless you happen to have a fault line running through the county). Any vectors from the origin CORS could be used to directly compute the local coordinates.
Some communities have done so already, I know one that is still using NAD83(86) coordinates and have a new broadcasting CORS that the county installed, they give you offsets to use for the NAD83(86) along with the NAD83(2011) that the CORS station is broadcasting.
Very simple to use; they don't want to extinguish all the data that has been collected over the years, yet they wish to slowly move forward.
I still don't get it. Right now you take GPS readings in ITRF and OPUS or your software converts to NAD83(2011) and NAVD88. NGS wants to to improve the new datum fit both horizontally and vertically, and therefore it isn't precisely NAD83 and NAVD88 any more. The values shift a bit and it gets a new name.
But other than tweaking a few constants and the geoid, making it 3D instead of 2D+1D, how is a new dynamic datum any different from what happens now?
If truly dynamic it will not be FIXED to the north american plate, hence coordinates will change over time. A compromise would be to fix it at a certain epoch, say 2022.00, but then it would need to be updated after X number of years, sort of like a stair step effect rather than a smooth sloped line. Either way there are myriad problems to be resolved.
I thought it was going to be fixed to ITRF at a particular epoch (which wouldn't be dynamic anymore). Is that not correct?
Here is what they are currently saying on the NGS pages:
When the new reference frames are adopted, will NGS geodetic survey mark datasheets and related products reflect a position at a certain epoch or will the information be dynamic (i.e. positional information at the time of the information request?)
This issue has been discussed at length, but NGS is still determining the best approach to both address the EarthÛªs dynamic nature and the user communityÛªs application of geodetic control. If NGS provided dynamic positional information, there would be scientific and resource-management advantages in adopting and providing globally recognized International Terrestrial Reference Frame (ITRF) coordinates and velocities.
Providing static positional information would be consistent with the historical practices of publishing coordinates on points in the USA-centric datum, but this practice fails to recognize the dynamic nature of the Earth and is inconsistent with the scientific underpinnings of geodetic science. Considering the speed with which centimeter-accurate positioning is readily becoming available, and the fact that every location in the USA has a changing horizontal position measurable in centimeters per year, NGS views the continued propagation of non-dynamic coordinates by themselves to be in unsupportable. Rather, some balance must be struck between historic practices and the truthful representation of points through geodesy. NGS continues to seek out user feedback on that balance.
Australia is going for a fixed epoch AND a dynamic datum.
I'm just going to cut and paste my rant from here ( https://surveyorconnect.com/community/threads/another-problem-with-coordinate-systems.327683/ ).
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This is an interesting issue. I'm not worried for myself as surveyors who deal with small parcels of data wont be affected that much, however I believe the entire decision making process by ISCM ( http://www.icsm.gov.au/index.html ) was flawed.
The main driver of the issue in Australia is that they powers that be think that by 2020 everyone will have a mobile phone that will give them accurate 0.5m coordinates. Then the 1.8m shift will become apparent to everyone, not just surveyors.
See here for full documents ( http://www.icsm.gov.au/geodesy/modern.html ) and ( http://www.icsm.gov.au/gda2020/index.html ).
From that site with my comments in red.
The major trends identified by the PCG include:
- The fully operational and enhanced global and regional satellite navigation constellations including Galileo (Europe), GPS (USA), GLONASS (Russia), Beidou (China), QZSS (Japan) and IRNSS (India) that will enable affordable consumer grade GNSS positioning to better than 50 cm accuracy and augmented positioning to better than 3 cm accuracy in realÛÒtime. The issue here is that they are talking about each of the millions of users as if they are individual. Instead it should be remembered that all of these users will be using only a few thousand apps. Why not write the conversion software for ios, android, etc and distribute it freely?
- A growing economic dependence on highly accurate positioning to underpin efficient transportation, spatially enabled business and government, and industrial automation (e.g., robotic mining and precision agriculture). The two best examples of the growing economic dependence are listed as robotic mining and precision agriculture. Robotic mining would be using a mine site datum and/or base station which moves with Australia. Precision ag is the same. If they use a CORS or have their own base, the moving Australian plate has no affect on them.
- A growing reliance on spatially enabled business processes that in turn utilise machine to machine (M2M) communication of highÛÒaccuracy positions and high resolution geospatial data in real time and three dimensions. This can happen regardless whether the current coordinate system or new one is used.
- Globalisation of coordinate and geodetic frameworks as a result of increased global services, the development and widespread adoption of nonÛÒAustralian consumer (nonÛÒenterprise) geospatial applications. See the first red comment.
- Many users including those in the transportation sectors (aviation, maritime and road) operate within globalised frameworks that are constrained by requirements that limit the support of individual national datum and have a necessity to conform to international standards.There are different laws and regulations in every country (and lots of differences within countries too) of the world and now apparently Australia is not allowed to be different on this issue??
It has been demonstrated that most people care about relative position, not coordinates. All they want to know is how far they are away from something, not the exact lat long (or utm or ?) coords. Why stuff around with the background numbers then?
The people most affected by this are the municipal authorities, service owners, etc that have lots of GIS data. They will see no benefit from this change and bear the majority of the costs. I'm just hoping that these organisations have a sufficient budget to enable GIS staff to properly address the issue because if they don't there will be some interesting times ahead.
Apparently organisations are supposed to be able to prepare and convert at their own leisure. This ignores the fact of the increased reliance on CORS. The real truth is that the majority will have to convert at the same time as the CORS networks. So much for choice!
The Australia proposal is a two stage one. Starting 1 Jan 2017, the coordinate system will shift approx 1.8m and then starting 1 Jan 2020, the fixed system (that starts 1/1/2017) will operate together with a fully dynamic datum. The issues will come with inadequate meta data so a coordinate may be the old MGA1994, the new MGA2020 or the new MGA dynamic. All three coords for the same point in the ground will be within 2m or each other!
No cost benefit report has been done. I attended an ISCM meeting last year and asked about this and got shrugs as a response. They are fiddling with national infrastructure with no idea of the eventual cost. I am just glad that the same people are not in charge of the roads here as their decision process would lead to the something like this: "the majority of the world has left hand drive cars so we should too to save car makers the inconvenience of making right hand drive cars" and order the change with very little thought to the costs and consequences of such a decision.
What do US surveyors think considering that you will be addressing the same issues come 2025?
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Input from a surveyor in Australia. We have been told that the onboard software and office software will "take care of it". Speaking to the local manufacturer distributors, they currently aren't sure what form this will be in but a lot of people have fingers crossed between now and 2020.
The local govt authorities have been great about this. They have constantly been in contact to keep us up to date.
Bill93, post: 386857, member: 87 wrote: I still don't get it. Right now you take GPS readings in ITRF and OPUS or your software converts to NAD83(2011) and NAVD88. NGS wants to to improve the new datum fit both horizontally and vertically, and therefore it isn't precisely NAD83 and NAVD88 any more. The values shift a bit and it gets a new name.
But other than tweaking a few constants and the geoid, making it 3D instead of 2D+1D, how is a new dynamic datum any different from what happens now?
Bill,
It will not be a 3D datum, it will be a 4D datum.
Paul in PA
mattb, post: 386904, member: 8629 wrote: Input from a surveyor in Australia. We have been told that the onboard software and office software will "take care of it". Speaking to the local manufacturer distributors, they currently aren't sure what form this will be in but a lot of people have fingers crossed between now and 2020.
The local govt authorities have been great about this. They have constantly been in contact to keep us up to date.
I'm intrigued. Just what have they kept you up to date about? All there is at the moment is a proposal that on 1/01/2017 (only four and bit short months away) we are supposed to move to GDA2020 and then a few years after that move to the dynamic. They (ICSM et al) have all said that we can all move "when we want and are ready". I would be interested to see who if anyone is going to move to GDA2020 and use it on 1/01/2017.
When is sufficient software going to be released?
What is the date when CORS is moving?
Can CORS operate on GDA94 and GDA2020 at the same time (user preference)?
What is the date that your relevant state, local gov and utility companies are moving on?
Unfortunately, all there has been to date is a big announcement and ICSM etc are hoping that ESRI, OMNISTAR, etc, etc meet the deadline that ICSM has set. Until some of the above questions have been answered properly, the fact remains that everything is very rubbery.
Our most recent example of government doing high powered IT work didn't go so well to put it mildly. I hope IBM Australia have nothing to do with the datum stuff.
Another thing that I just found that as of 2nd August, the transformation parameters for GDA2020 have not been released.
How long has this been talked about and one of the basic instruments that has to be used for this whole process has yet to be finalised.
Less hot air being released by bureaucrats and more work from them please as they are the ones obligating a lot of people to do a lot of work that they (government bureaucrats) are not contributing towards.
Also per another section of the same announcement from 2nd August, they have only collated a list of software providers to talk to. A "contact schedule is being developed".....
They are only four and a bit short months away from their own deadline and this is the best they can do?
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http://www.icsm.gov.au/gda2020/gmiwg.html
GDA2020 definition and GDA94 àÓ GDA2020 transformation parameters
GDA2020 coordinates of the CORS stations defining the GDA2020 datum and the values for the 3D 7 parameter similarity transformation relating GDA94 to GDA2020 and vice-versa are close to being finalised by Geoscience Australia.
A CRCSI project, being undertaken by a CRCSI 43pl Partner, has been initiated to update the NTv2 gridding software developed for the AGD66ã84 to GDA94 transformations. The scope of the project includes 3D (E,N,U) grids with uncertainties.
These products are scheduled to be delivered by October 2016.
Engagement with Spatial Software Providers
A list of over 80 spatial software ã hardware providers has been collated and a contact schedule is being developed whereby these entities will be directly informed of AustraliaÛªs Datum Modernisation Plans and the availability of GDA2020 information.
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Here today there tomorrow.
A few random thoughts...
The PLSS was developed with geodetic principals in mind. While not perfect, it is brilliantly repeatable. At the end of the day those with a hand developing it were smart enough to declare original corners absolute. We would do well to remember this.
I began dabbling in geodesy in the late 70s. When you pull data from sources in nearly a dozen countries you get the basics quick. There was no school associated with Army Infantry then to teach it, so I read (a lot). 25 years later I took college algebra. That is my one and only college math course. The math we use isn't incredibly complex. Combine this with the fact that even a PHD in mathematics won't help identify a correct corner, and only 1 conclusion is possible. As valuable as education is we are over the top requiring a four year degree. Even Engineers in nearly every State have an exceptional candidate provision. It is wrong for us to close that door.
I have watched our Profession dwindle as a percentage of numerous groups over the years. Most construction sites have robots and GPS run by electricians, carpenters and others. Researchers and Scientists have dropped off of my client list almost entirely. We are becoming a minority market because we simply aren't needed. This won't change by requiring us to learn the things others can do for themselves. And again, it won't help me correctly recover a boundary.
The change to a dynamic datum will require little beyond intermediate algebra. Local policy can still control local practice. I agree we need to be aware and participate in these changes. It doesn't have to be painful or distressing..
Ramble mode off... T
Hi Seb, yes ABS ran a census through IBM and 100% of Surveyors that successfully completed it said they were very happy with how things are going. *difficult to show sarcasm.
To be honest our state government are attempting to keep us up to date but at present they are keeping us up to date by letting us know that it is going to happen and it will be staged over the next few years. That's about the extent of it at present.
This thread make me so HAPPY that I will be retiring prior to 2022!!!
Maybe new State Plane Coordinate Systems can be designed to shift at the origin to keep grid values consistent. Most surveyors won't care that the geodetic coordinates are changing as long as the grid values remain the same.
LDP systems would make sense. Limiting the size of the system such that local velocities are practically the same throughout the system.
Spent all day in an educational program with Jan Van Sickle as the presenter. Way too many numbers and letters for this dinosaur. Had fun trying to keep up anyway. Another half day tomorrow. Something like 90 people taking it in today and I didn't appear to be the most ignorant one present. Probably in the bottom 20 percent, though. It was obvious that many who use GPS gear every day and have done so for years had trouble keeping up.
