[PROJ] NOAA VDatum Tidal Grids and PROJ CDN

[Brian Shaw]

All

Just a little background about VDatum, it is a transformation tool 
developed collaboratively by several offices at NOAA including: the 
Center for Operational Oceanographic Products (CO-OPS) that do tidal 
datums, tides and currents; the National Geodetic Survey (NGS) that do 
the datums, geoids and transformations; and the Office of Coast Survey 
(OCS) that make the nautical charts, do bathymetric surveying and more. 
https://vdatum.noaa.gov/ <https://vdatum.noaa.gov/> NGS makes sure to 
include the most recent NGS transformations into both VDatum and the NGS 
Coordinate Conversion and Transformation Tool (NCAT). 
https://geodesy.noaa.gov/NCAT/ <https://geodesy.noaa.gov/NCAT/>

I have seen a couple questions and comments in this thread and I wanted 
to respond to them.

@ Howard - NGS is participating with several scientists including myself 
in the OGC meetings for the deformation grids and developing the GGXF.  
We still need to work on getting all the NADCON 5 and probably the 
VERTCON 3 grids/transformations incorporated into EPSG.  We have also 
began working to try to provide our grids in GeoTiff formats  (currently 
xGEOID20 is the first one I believe) as well as working to get our tools 
using GeoTiff grids.  The long term plan is to use GGXF once developed 
and standardized but to work to implement GeoTiff until that time.

@ Greg - Our Chief Geodesist has been significantly involved with the 
ISO Geodetic Registry and I believe he has included all of the datum and 
transformation parameters and grids from NGS into the registry.  While 
EPSG is certainly the de facto standard I believe the desire is to have 
this registry be the official location for parameters sometime in the 
future.

@ Javier - You are correct that NGS is planning to modernize the NSRS 
(NAD 83, NAVD 88). The original plan was to update this by the end of 
2022 but with various delays in data collection and more we officially 
announced that it will be delayed. 
https://geodesy.noaa.gov/datums/newdatums/delayed-release.shtml 
<https://geodesy.noaa.gov/datums/newdatums/delayed-release.shtml>

If interested there are 3 Blueprint Documents that go into great detail 
about the upcoming changes.  We have been working on updating all of the 
documents and those updates should be available by the end of February 
as they are currently in review. We have been collaborating with the 
Canadians and actually just had a meeting with them earlier today.
https://geodesy.noaa.gov/datums/newdatums/policy.shtml 
<https://geodesy.noaa.gov/datums/newdatums/policy.shtml>

Please don't hesitate to email me with any questions.

Cheers
Brian


On 12/16/2020 9:04 AM, Javier Jimenez Shaw wrote:
> CDN is a nice place to store big projects. And it is actually great 
> that they want to use PROJ "format" to publish it. However, as Even 
> and Greg mentioned, there are other use cases where you need it 
> locally in your computer/device. If it is it planned to be in 
> PROJ-data, maybe I should buy a new hard drive ;)
>
> If I am not wrong, NOAA (or other institution) is upgrading the 
> American horizontal and vertical CRSs in 2022. I could imagine that 
> they will publish the Tidal Grids referred to the new ones once 
> published. Am I right?
>
> I am curious which data is that, that takes 12GB. Can we see it somewhere?
>
> Cheers,
> Javier
> .___ ._ ..._ .. . ._.  .___ .. __ . _. . __..  ... .... ._ .__
> Entre dos pensamientos racionales
> hay infinitos pensamientos irracionales.
>
>
>
> On Wed, 16 Dec 2020 at 15:53, Howard Butler <howard at hobu.co 
> <mailto:howard at hobu.co>> wrote:
>
>
>
>     > On Dec 16, 2020, at 8:44 AM, Greg Troxel <gdt at lexort.com
>     <mailto:gdt at lexort.com>> wrote:
>     >
>     >
>     > Howard Butler <howard at hobu.co <mailto:howard at hobu.co>> writes:
>     >
>     >> IMO, NOAA seeking to put 12gb of specialized shift files into
>     the CDN
>     >> is *exactly* what we were hoping to have happen with the CDN
>     >> project. They're simply too big to deliver via normal package,
>     but the
>     >> convenience the CDN can provide for users of these grids is
>     >> substantial. I hope NOAA can close the loop with EPSG and
>     participate
>     >> in the OGC standardization effort that is ongoing with respect to
>     >> deformation grids and their format as well.
>     >
>     > Thanks for explaining.  I really meant simply that I did not
>     understand
>     > and was thus being careful not to opine if this was ok or not.
>
>     OK for NOAA to do this or ok for the PROJ project to support it
>     with its CDN? I don't know about the former either, but the past
>     NOAA public transition path for this kind of data was to toss it
>     into the ether in their own format and hope for implementation. I
>     would hope supporting PROJ and modernizing their grid deliveries
>     with Cloud Optimized GeoTIFF would be under their purview.
>
>     As for the CDN, we can put a lot of data up there before anyone is
>     going to complain. The URL is purposefully the project's instead
>     of an Amazon one to allow us to gracefully migrate in case AWS
>     decides supporting us is no longer in their interest.
>
>     Howard
>
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-- 
*************************************
Brian Shaw
Rocky Mountain Regional Advisor (CO, MT, WY)
NOAA's National Geodetic Survey (NGS)
Cell Phone # 240-988-6363

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