Definition of a unit of measure which is defined through algebraic combination of more primitive units, which are usually base units from a particular system of units. Derived units based directly on base units are usually preferred for quantities other than the base units or fundamental quantities within a system. If a derived unit is not the preferred unit, the ConventionalUnit element should be used instead.
Database handle for the object. It is of XML type ID, so is constrained to be unique in the XML document within which it occurs. An external identifier for the object in the form of a URI may be constructed using standard XML and XPointer methods. This is done by concatenating the URI for the document, a fragment separator, and the value of the id attribute.
Source
<complexType name="DerivedUnitType"><annotation><documentation>Definition of a unit of measure which is defined through algebraic combination of more primitive units, which are usually base units from a particular system of units. Derived units based directly on base units are usually preferred for quantities other than the base units or fundamental quantities within a system. If a derived unit is not the preferred unit, the ConventionalUnit element should be used instead.</documentation></annotation><complexContent><extension base="gml:UnitDefinitionType"><sequence><element ref="gml:derivationUnitTerm" maxOccurs="unbounded"/></sequence></extension></complexContent></complexType>