[PROJ] Fwd: some help with cm-level GRS80 to WGS-84 transformation?

[Kirk Waters - NOAA Federal]

I'm sure others with more experience will jump in, but I think the main
issue here is that WGS84 is a family of reference frames that are all based
on the GRS80 ellipsoid. So, the problem doesn't exactly make sense and the
various realizations of WGS84 differ at the cm level. Are you perhaps
trying to go from a NAD83 realization (such as NAD83(2011)) to a WGS84
realization (maybe ITRF14
or something)?

Kirk Waters, PhD
NOAA Office for Coastal Management
Applied Sciences Program
‪Phone: 843-284-6962‬ (New as of 2022)
coast.noaa.gov/digitalcoast




On Wed, Jan 19, 2022 at 3:55 PM Joseph Boardman <boardman at aigllc.com> wrote:

>
>
>
> -------- Forwarded Message --------
> Subject: some help with cm-level GRS80 to WGS-84 transformation?
> Date: Wed, 19 Jan 2022 11:28:24 -0700
> From: Joseph Boardman <boardman at aigllc.com> <boardman at aigllc.com>
> To: proj at lists.osgeo.org
>
> Dear Proj Experts,
>
> I'm a remote sensing geophysicist with experience in geodesy and mapping.
>
> Right now I'm struggling trying to get a high-accuracy proj command to
> convert from GRS80 to WGS-84 at the cm level.
>
> Any clues? cs2cs is not doing it.
>
> cs2cs +proj=lonlat +ellps=WGS84 +to +proj=lonlat +ellps=GRS80 -d 8
> -120 40
> -120.00000000   40.00000000 0.00000000
>
> Do I need to do a transformation pipeline per the 8.2.1 docs and use a
> Helmert transform? Any help much appreciated.
>
> Best,
>
> Joe
>
>
> _______________________________________________
> PROJ mailing list
> PROJ at lists.osgeo.org
> https://lists.osgeo.org/mailman/listinfo/proj
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20220119/bdb16059/attachment.html>