Field Definitions are Available Here
Collection
float(8)
Mandatory if applicable
SemiMajorAxis
6378137
EllipsoidName, DenominatorofFlatteningRatio
6378137
Must be used with EllipsoidName, DenominatorofFlatteningRatio.
METADATA > COLLECTIONMETADATA > Spatial > CoordinateSystemContainer > HorizontalCoordinateSystemContainer > GeodeticModel.SemiMajorAxis
TBD
MD_Dimension see also CT_Coordinate system axis
Spatial Information