[PROJ] WGS84/NAD83 Original to {current} transforms

[Nicolas Cadieux]



Hi,
You probably found this but I am posting anyways in case you did not

http://www.naref.org/transf/nad83_hydroscan2006.pdf

https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ntv2.php?locale=en

https://www.nrcan.gc.ca/maps-tools-and-publications/tools/geodetic-reference-systems-tools/tools-applications/10925#Epochs

Look for Trx and NTv2 tools.

Nicolas



>> Le 22 nov. 2019 à 17:41, mhw-at-yg <matt.wilkie at gov.yk.ca> a écrit :
> Hello,
> 
> Within the Yukon and NWT (Canada), how do you convert spatial data
> horizontal datum from NAD83-Original (circa 1994) to NAD83-CSRS (2002+)?
> 
> I’ve been up and down NRCAN’s geodetic reference site[0] and a bunch of
> other ones and am more confused than when I started. The consensus on the
> net seems to be to use NTv2 to migrate from Original to CSRS, but there are
> no grid shift files for the territories [1],[2].
> 
> Esri (ArcGIS Desktop) and Safe (FME) use transforms which are a null
> operation, all that happens is a change in the name, the coordinates are
> left unaltered. However looking at the v7 velocity grid[3] it looks like
> there have been significant shifts since the 1990s.
> 
> Most of our new data acquisitions from survey and LiDAR are coming in as
> CSRS. When combining with our old data and project-on-the-fly I’ve observed
> different coordinates for the same points depending on how the locations are
> reported. So we need to bring our holdings into a common coordinate system
> to be assured our analyses are the most correct they can be, but how?
> 
> [0]:
> https://www.nrcan.gc.ca/maps-tools-and-publications/tools/geodetic-reference-systems/18766
> [1]: https://webapp.geod.nrcan.gc.ca/geod/tools-outils/grids.php (List)
> [2]: https://webapp.geod.nrcan.gc.ca/geod/data-donnees/transformations.php
> (Download, sign in but free account)
> [3]: https://webapp.geod.nrcan.gc.ca/geod/tools-outils/nad83-docs.php
> 
> Thanks in advance for your advice,
> 
> Matt Wilkie
> Geomatics Analyst
> Environment | Information Management & Technology
> T 867-667-8133 | Yukon.ca
> 
> 
> 
> 
> -----
> -Matt
> --
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