EPSG:7969

NGVD29 height (m) to NAVD88 height (1)

Attributes

Geodetic CRS: NGVD29 height (ftUS)

Datum: National Geodetic Vertical Datum 1929

Data source: EPSG

Information source: National Geodetic Survey, www.ngs.noaa.gov

Revision date: 2019-09-17

Scope: Change of height to a different vertical reference surface.

Remarks: In this area the NGVD29 vertical reference surface is approximately 0.6 to 1.6m below the NAVD88 datum surface. Interpolation within the gridded data file may be made using either NAD27 or any of the realizations of NAD83 applicable to US conus.

Method: Vertical Offset by Grid Interpolation (VERTCON)

Area of use: United States (USA) - CONUS west of 107°W - onshore - Arizona; California; Colorado; Idaho; Montana; Nevada; New Mexico; Oregon; Utah; Washington; Wyoming.

Description: (0,)

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Definition: OGC Well Known Text 2 (2019)

COORDINATEOPERATION["NGVD29 height (m) to NAVD88 height (1)",
    VERSION["NGS-US Conus W"],
    SOURCECRS[
        VERTCRS["NGVD29 height (m)",
            VDATUM["National Geodetic Vertical Datum 1929"],
            CS[vertical,1],
                AXIS["gravity-related height (H)",up,
                    LENGTHUNIT["metre",1]],
            ID["EPSG",7968]]],
    TARGETCRS[
        VERTCRS["NAVD88 height",
            VDATUM["North American Vertical Datum 1988"],
            CS[vertical,1],
                AXIS["gravity-related height (H)",up,
                    LENGTHUNIT["metre",1]],
            ID["EPSG",5703]]],
    METHOD["Vertical Offset by Grid Interpolation (VERTCON)",
        ID["EPSG",9658]],
    PARAMETERFILE["Vertical offset file","vertconw.94"],
    OPERATIONACCURACY[0.02],
    USAGE[
        SCOPE["Change of height to a different vertical reference surface."],
        AREA["United States (USA) - CONUS west of 107°W - onshore - Arizona; California; Colorado; Idaho; Montana; Nevada; New Mexico; Oregon; Utah; Washington; Wyoming."],
        BBOX[31.33,-124.79,49.05,-107]],
    ID["EPSG",7969],
    REMARK["In this area the NGVD29 vertical reference surface is approximately 0.6 to 1.6m below the NAVD88 datum surface. Interpolation within the gridded data file may be made using either NAD27 or any of the realizations of NAD83 applicable to US conus."]]

Definition: PROJ.4

+proj=vgridshift +grids=us_noaa_vertconw.tif +multiplier=1

Definition: JavaScript (Proj4js)

proj4.defs("EPSG:7969","+proj=vgridshift +grids=us_noaa_vertconw.tif +multiplier=1");

Definition: JSON

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "Transformation",
    "name": "NGVD29 height (m) to NAVD88 height (1)",
    "source_crs": {
        "type": "VerticalCRS",
        "name": "NGVD29 height (m)",
        "datum": {
            "type": "VerticalReferenceFrame",
            "name": "National Geodetic Vertical Datum 1929"
        },
        "coordinate_system": {
            "subtype": "vertical",
            "axis": [
                {
                    "name": "Gravity-related height",
                    "abbreviation": "H",
                    "direction": "up",
                    "unit": "metre"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 7968
        }
    },
    "target_crs": {
        "type": "VerticalCRS",
        "name": "NAVD88 height",
        "datum": {
            "type": "VerticalReferenceFrame",
            "name": "North American Vertical Datum 1988"
        },
        "coordinate_system": {
            "subtype": "vertical",
            "axis": [
                {
                    "name": "Gravity-related height",
                    "abbreviation": "H",
                    "direction": "up",
                    "unit": "metre"
                }
            ]
        },
        "id": {
            "authority": "EPSG",
            "code": 5703
        }
    },
    "method": {
        "name": "Vertical Offset by Grid Interpolation (VERTCON)",
        "id": {
            "authority": "EPSG",
            "code": 9658
        }
    },
    "parameters": [
        {
            "name": "Vertical offset file",
            "value": "vertconw.94",
            "id": {
                "authority": "EPSG",
                "code": 8732
            }
        }
    ],
    "accuracy": "0.02",
    "scope": "Change of height to a different vertical reference surface.",
    "area": "United States (USA) - CONUS west of 107°W - onshore - Arizona; California; Colorado; Idaho; Montana; Nevada; New Mexico; Oregon; Utah; Washington; Wyoming.",
    "bbox": {
        "south_latitude": 31.33,
        "west_longitude": -124.79,
        "north_latitude": 49.05,
        "east_longitude": -107
    },
    "id": {
        "authority": "EPSG",
        "code": 7969
    },
    "remarks": "In this area the NGVD29 vertical reference surface is approximately 0.6 to 1.6m below the NAVD88 datum surface. Interpolation within the gridded data file may be made using either NAD27 or any of the realizations of NAD83 applicable to US conus."
}

Definition: MapServer - MAPfile

PROJECTION
	"proj=vgridshift"
	"grids=us_noaa_vertconw.tif"
	"multiplier=1"
END

Definition: Mapnik

<?xml version="1.0" encoding="utf-8"?>
<Map srs="+proj=vgridshift +grids=us_noaa_vertconw.tif +multiplier=1">
	<Layer srs="+proj=vgridshift +grids=us_noaa_vertconw.tif +multiplier=1">
	</Layer>
</Map>

Definition: SQL (PostGIS)

INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 7969, 'EPSG', 7969, '+proj=vgridshift +grids=us_noaa_vertconw.tif +multiplier=1', 'None');