EPSG:1423

London Survey Grid height datum

Attributes

Data source: EPSG

Information source: Transport for London, Topographic surveys and mapping Standard S1026, issue A4, May 2025.

Revision date: 2025-10-28

Scope: Engineering survey and topographic mapping for transport applications.

Remarks: LSGH is an orthometric height datum chosen to provide positive values for areas of interest to London Underground (LU).

Area of use: United Kingdom (UK) - Greater London and surrounding area.

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WGS84 bounds:
0.8 51.1
-1.33 52.0

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Definition: OGC Well Known Text

VERT_DATUM["London Survey Grid height datum",2005,
    AUTHORITY["EPSG","1423"]]

Definition: OGC Well Known Text 2 (2019)

VDATUM["London Survey Grid height datum",
    ID["EPSG",1423]]

Definition: ESRI Well Known Text

VDATUM["London_Survey_Grid_height_datum"]

Definition: JSON

{
    "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json",
    "type": "VerticalReferenceFrame",
    "name": "London Survey Grid height datum",
    "scope": "Engineering survey and topographic mapping for transport applications.",
    "area": "United Kingdom (UK) - Greater London and surrounding area.",
    "bbox": {
        "south_latitude": 51.1,
        "west_longitude": -1.33,
        "north_latitude": 52,
        "east_longitude": 0.8
    },
    "id": {
        "authority": "EPSG",
        "code": 1423
    }
}

Definition: GeoServer

1423-datum=VERT_DATUM["London Survey Grid height datum",2005,AUTHORITY["EPSG","1423"]]