metre
EPSG
http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/egm08_wgs84.html
2019-07-17
Geodesy.
Zero-height surface resulting from the application of the EGM2008 geoid model to the WGS 84 ellipsoid. Replaces EGM96 height (CRS code 5773).
Definition: OGC Well Known Text 2 (2019)
VERTCRS["EGM2008 height", VDATUM["EGM2008 geoid"], CS[vertical,1], AXIS["gravity-related height (H)",up, LENGTHUNIT["metre",1]], USAGE[ SCOPE["Geodesy."], AREA["World."], BBOX[-90,-180,90,180]], ID["EPSG",3855]]
Definition: JSON
{ "$schema": "https://proj.org/schemas/v0.7/projjson.schema.json", "type": "VerticalCRS", "name": "EGM2008 height", "datum": { "type": "VerticalReferenceFrame", "name": "EGM2008 geoid" }, "coordinate_system": { "subtype": "vertical", "axis": [ { "name": "Gravity-related height", "abbreviation": "H", "direction": "up", "unit": "metre" } ] }, "scope": "Geodesy.", "area": "World.", "bbox": { "south_latitude": -90, "west_longitude": -180, "north_latitude": 90, "east_longitude": 180 }, "id": { "authority": "EPSG", "code": 3855 } }
Definition: Mapnik
<?xml version="1.0" encoding="utf-8"?> <Map srs="+vunits=m +no_defs +type=crs"> <Layer srs="+vunits=m +no_defs +type=crs"> </Layer> </Map>
Definition: SQL (PostGIS)
INSERT into spatial_ref_sys (srid, auth_name, auth_srid, proj4text, srtext) values ( 3855, 'EPSG', 3855, '+vunits=m +no_defs +type=crs', 'VERT_CS["EGM2008 height",VERT_DATUM["EGM2008 geoid",2005,AUTHORITY["EPSG","1027"]],UNIT["metre",1,AUTHORITY["EPSG","9001"]],AXIS["Gravity-related height",UP],AUTHORITY["EPSG","3855"]]');