The optional linearUnit attribute defines the unit used by StatsWithTolLinearType.
Source
<xs:element name="RoughnessAverageValueStats" type="StatsWithTolLinearType" minOccurs="0"><xs:annotation><xs:documentation>The optional RoughnessAverageValueStats element is the result of a statistical evaluation of measured Roughness Average (Ra) values.</xs:documentation></xs:annotation></xs:element>
<xs:complexType name="SurfaceTextureCharacteristicStatsEvalType"><xs:annotation><xs:documentation>The SurfaceTextureCharacteristicStatsEvalType defines the results of a statistical evaluation of measured surface texture characteristics.</xs:documentation></xs:annotation><xs:complexContent><xs:extension base="CharacteristicStatsEvalBaseType"><xs:sequence><xs:element name="RoughnessAverageValueStats" type="StatsWithTolLinearType" minOccurs="0"><xs:annotation><xs:documentation>The optional RoughnessAverageValueStats element is the result of a statistical evaluation of measured Roughness Average (Ra) values.</xs:documentation></xs:annotation></xs:element></xs:sequence></xs:extension></xs:complexContent></xs:complexType>