EPSG:9326

COORDINATEOPERATION["NZGD2000 to NZVD2016 height (2)",
    VERSION["LINZ-NZ 2016 gtx"],
    SOURCECRS[
        GEOGCRS["NZGD2000",
            DATUM["New Zealand Geodetic Datum 2000",
                ELLIPSOID["GRS 1980",6378137,298.257222101,
                    LENGTHUNIT["metre",1]]],
            PRIMEM["Greenwich",0,
                ANGLEUNIT["degree",0.0174532925199433]],
            CS[ellipsoidal,3],
                AXIS["geodetic latitude (Lat)",north,
                    ORDER[1],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["geodetic longitude (Lon)",east,
                    ORDER[2],
                    ANGLEUNIT["degree",0.0174532925199433]],
                AXIS["ellipsoidal height (h)",up,
                    ORDER[3],
                    LENGTHUNIT["metre",1]],
            ID["EPSG",4959]]],
    TARGETCRS[
        VERTCRS["NZVD2016 height",
            VDATUM["New Zealand Vertical Datum 2016"],
            CS[vertical,1],
                AXIS["gravity-related height (H)",up,
                    LENGTHUNIT["metre",1]],
            ID["EPSG",7839]]],
    METHOD["Geographic3D to GravityRelatedHeight (gtx)",
        ID["EPSG",9665]],
    PARAMETERFILE["Geoid (height correction) model file","nzgeoid2016.gtx"],
    OPERATIONACCURACY[0.1],
    USAGE[
        SCOPE["Derivation of gravity-related heights from GNSS observations."],
        AREA["New Zealand - onshore and offshore. Includes Antipodes Islands, Auckland Islands, Bounty Islands, Chatham Islands, Cambell Island, Kermadec Islands, Raoul Island and Snares Islands."],
        BBOX[-55.95,160.6,-25.88,-171.2]],
    ID["EPSG",9326],
    REMARK["Defines NZVD2016 vertical datum (datum code 1169, CRS code 7839). Supersedes NZGD2000 to NZVD2016 height (1) (code 7840) after change of grid file format. For reversible alternative to this CT see NZGD2000 to NZGD2000 + NZVD2016 height (2) (code 9628)."]]

proj4.defs("EPSG:9326","+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +inv +proj=vgridshift +grids=nz_linz_nzgeoid2016.tif +multiplier=1 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1");

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "Transformation",
    "name": "NZGD2000 to NZVD2016 height (2)",
    "source_crs": {
        "type": "GeographicCRS",
        "name": "NZGD2000",
        "datum": {
            "type": "GeodeticReferenceFrame",
            "name": "New Zealand Geodetic Datum 2000",
            "ellipsoid": {
                "name": "GRS 1980",
                "semi_major_axis": 6378137,
                "inverse_flattening": 298.257222101
            }
        },
        "coordinate_system": {
            "subtype": "ellipsoidal",
            "axis": [
                {
                    "name": "Geodetic latitude",
                    "abbreviation": "Lat",
                    "direction": "north",
                    "unit": "degree"
                },
                {
                    "name": "Geodetic longitude",
                    "abbreviation": "Lon",
                    "direction": "east",
                    "unit": "degree"
                },
                {
                    "name": "Ellipsoidal height",
                    "abbreviation": "h",
                    "direction": "up",
                    "unit": "metre"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 4959
        }
    },
    "target_crs": {
        "type": "VerticalCRS",
        "name": "NZVD2016 height",
        "datum": {
            "type": "VerticalReferenceFrame",
            "name": "New Zealand Vertical Datum 2016"
        },
        "coordinate_system": {
            "subtype": "vertical",
            "axis": [
                {
                    "name": "Gravity-related height",
                    "abbreviation": "H",
                    "direction": "up",
                    "unit": "metre"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 7839
        }
    },
    "method": {
        "name": "Geographic3D to GravityRelatedHeight (gtx)",
        "id": {
            "authority": "EPSG",
            "code": 9665
        }
    },
    "parameters": [
        {
            "name": "Geoid (height correction) model file",
            "value": "nzgeoid2016.gtx",
            "id": {
                "authority": "EPSG",
                "code": 8666
            }
        }
    ],
    "accuracy": "0.1",
    "scope": "Derivation of gravity-related heights from GNSS observations.",
    "area": "New Zealand - onshore and offshore. Includes Antipodes Islands, Auckland Islands, Bounty Islands, Chatham Islands, Cambell Island, Kermadec Islands, Raoul Island and Snares Islands.",
    "bbox": {
        "south_latitude": -55.95,
        "west_longitude": 160.6,
        "north_latitude": -25.88,
        "east_longitude": -171.2
    },
    "id": {
        "authority": "EPSG",
        "code": 9326
    },
    "remarks": "Defines NZVD2016 vertical datum (datum code 1169, CRS code 7839). Supersedes NZGD2000 to NZVD2016 height (1) (code 7840) after change of grid file format. For reversible alternative to this CT see NZGD2000 to NZGD2000 + NZVD2016 height (2) (code 9628)."
}

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +inv +proj=vgridshift +grids=nz_linz_nzgeoid2016.tif +multiplier=1 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1">
	<Layer srs="+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +inv +proj=vgridshift +grids=nz_linz_nzgeoid2016.tif +multiplier=1 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1">
	</Layer>
</Map>

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 9326, 'EPSG', 9326, '+proj=pipeline +step +proj=axisswap +order=2,1 +step +proj=unitconvert +xy_in=deg +xy_out=rad +step +inv +proj=vgridshift +grids=nz_linz_nzgeoid2016.tif +multiplier=1 +step +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1', 'None');