Field Definitions are Available Here
Collection
varstring(20)
Mandatory if applicable
Units in which depths are recorded.
fathoms
DepthDatumName, DepthEncodingMethod, DepthResolution
fathoms
Must be used with DepthDatumName, DepthEncodingMethod, DepthResolution.
METADATA > COLLECTIONMETADATA > Spatial > CoordinateSystemContainer > VerticalCoordinateSystemContainer > DepthSystemDefinition.DepthDistanceUnits
See also CD_VerticalDatum and CD_VerticalDatumType in 19111 /gmi:MI_Metadata/gmd:referenceSystemInfo/gmd:MD_ReferenceSystem/gmd:referenceSystemIdentifier/gmd:RS_Identifier/gmd:authority/gmd:CI_Citation/gmd:title/gco:CharacterString
Spatial Information