Could anyone direct me to some information on the difference between WGS84 positions and what is returned on the OPUS results – IGS08 (EPOCH:2014.2408)
I have an aerospace client that is requesting WGS84 positions for their calculations and I am having trouble finding a definitive answer to that request.
Maybe I am not able to generate correct WGS84 positions through OPUS?
This is a weak area in my knowledge.
Thanks
Dave Doyle (base9geodesy) just covered this at the OGUG workshop yesterday.
Refer to this:
http://earth-info.nga.mil/GandG/publications/tr8350.2/tr8350_2.html
I believe that ITRF08=IGS08
Also look at the HTDP tool on the NGS website.
https://www.ngs.noaa.gov/TOOLS/Htdp/Htdp_transform.html
Good luck.
If I'm reading all of those links correctly then the latest iterations of WGS84, ITRF08, and IGS08 are all the same. Good info, thanks for sharing.
Thanks for the info, much is very technical and is better understood by a geodesist than a simple surveyor such as myself but I did some conversions with the NGS link you provided and the answers show current IGS08 to be the same as current WGS84.
Perfect for what I need.
🙂
You are welcome. I would probably also confirm with you State Geodetic advisor if available to make sure you are taking all of the correct factors into account in your conversion.
Good Luck!
State geodetic advisor, didn’t know there was such a person.
Just an observation but all the info I have been reading has dates like 1994, 1996, 1997, 2000, 2001, 2002 but then it stops. It seems we have dropped the ball or at least through it to the sidelines since then. Have we put aside all this technical stuff since then to deal with healthcare or what?
Whoops,
I just looked on the NGS webpage. It looks like Alaska does not have a state advisor or a state coordinator.
You could always shoot an email to NGS to make sure you are approaching the problem correctly.
I don't have a solid answer regarding the dates.
Rest assured changes are coming!
Well, "same" depends on your level of accuracy as well as awareness of the impact of the differences in positions as a function of time.
Note that WGS 84 does not include a provision for velocities (neither does NAD 83). WGS84 is periodically "updated" to make it consistent with the current version of ITRF. They, NGA, have committed to maintain consistency at the 5 cm level.
Posted elsewhere on this site is some information about the upcoming new version of ITRF (ITRF2013).
Working with NAD83, WGS84 and ITRF coordinates requires that one knows the versions of each as well as the associated reference epoch as the epoch of interest.
Note as well that the transformation parameters between the most recent versions of ITRF are quite small. See the IGN site for the parameters.
DMM
Great suggestions and references. I appreciate the effort helping me learn.