[PROJ] setting default transformation NAD83 CSRS to / from NAD83 Original

[Even Rouault]

Travis,

in EPSG, the grid ON83CSv1 is registered for the transformation between 
NAD83 original and NAD83(CSRS) v3. Note the v3 suffix. So instead of UTM 
NAD83 CSRS (epsg:2958) you need to use "NAD83(CSRS)v3 / UTM zone 17N" 
(epsg:22317)

$ projinfo -s EPSG:22317 -t EPSG:26917 --spatial-test intersects -o PROJ 
--single-line -q
+proj=pipeline +step +inv +proj=utm +zone=17 +ellps=GRS80 +step +inv 
+proj=hgridshift +grids=ca_nrc_ON83CSv1.tif +step +proj=utm +zone=17 
+ellps=GRS80

$ echo 500000 5000000 | PROJ_NETWORK=ON PROJ_DEBUG=2 bin/cs2cs 
EPSG:22317 EPSG:26917
[...]
Using https://cdn.proj.org/ca_nrc_ON83CSv1.tif
500000.08    5000000.32 0.00

Even


Le 09/04/2025 à 20:58, Travis Kirstine via PROJ a écrit :
>
> Hi All,
>
> I’ve been struggling with trying to set proj to use 
> ca_nrc_ON27CSv1.tif grid as the default transformation when 
> transforming between UTM NAD83 CSRS (epsg:2958) and UTM NAD83 
> (epsgL26917) Original.
>
> In the past I’ve specified the +nadgrids=./ON83CSv1.gsb in the cs2cs 
> command but was hoping that I could just set the default value in the 
> proj.db to apply the gridshift.
>
> Is this possible?  I’ve run the projsync to pull the new version of 
> the grid but still no luck.
>
> Regards
>
>
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