Hydrography, drilling.
Approximate because not specific to any location or epoch. Users are advised to not use this generic CRS but instead use one with a specific datum origin (e.g. "Mean Sea Level at xxx during yyyy-yyyy") or defined through a specified geoid/hydroid model.
Definition: OGC Well Known Text 2 (2019)
VERTCRS["MSL depth (ft)", VDATUM["Mean Sea Level"], CS[vertical,1], AXIS["depth (D)",down, LENGTHUNIT["foot",0.3048]], USAGE[ SCOPE["Hydrography, drilling."], AREA["World."], BBOX[-90,-180,90,180]], ID["EPSG",8051]]
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "VerticalCRS", "name": "MSL depth (ft)", "datum": { "type": "VerticalReferenceFrame", "name": "Mean Sea Level" }, "coordinate_system": { "subtype": "vertical", "axis": [ { "name": "Depth", "abbreviation": "D", "direction": "down", "unit": { "type": "LinearUnit", "name": "foot", "conversion_factor": 0.3048 } } ] }, "scope": "Hydrography, drilling.", "area": "World.", "bbox": { "south_latitude": -90, "west_longitude": -180, "north_latitude": 90, "east_longitude": 180 }, "id": { "authority": "EPSG", "code": 8051 } }
Definition: Mapnik
<?xml version="1.0" encoding="utf-8"?> <Map srs="+vunits=ft +no_defs +type=crs"> <Layer srs="+vunits=ft +no_defs +type=crs"> </Layer> </Map>
Definition: SQL (PostGIS)
INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 8051, 'EPSG', 8051, '+vunits=ft +no_defs +type=crs', 'VERT_CS["MSL depth (ft)",VERT_DATUM["Mean Sea Level",2005,AUTHORITY["EPSG","5100"]],UNIT["foot",0.3048,AUTHORITY["EPSG","9002"]],AXIS["Depth",DOWN],AUTHORITY["EPSG","8051"]]');