Margins, page sizes, and distances are all measured in tenths to keep MusicXML data in a consistent coordinate system as much as possible. The translation to absolute units is done with the scaling type, which specifies how many millimeters are equal to how many tenths. For a staff height of 7 mm, millimeters would be set to 7 while tenths is set to 40. The ability to set a formula rather than a single scaling factor helps avoid roundoff errors.
<xs:complexType name="scaling"><xs:annotation><xs:documentation>Margins, page sizes, and distances are all measured in tenths to keep MusicXML data in a consistent coordinate system as much as possible. The translation to absolute units is done with the scaling type, which specifies how many millimeters are equal to how many tenths. For a staff height of 7 mm, millimeters would be set to 7 while tenths is set to 40. The ability to set a formula rather than a single scaling factor helps avoid roundoff errors.</xs:documentation></xs:annotation><xs:sequence><xs:element name="millimeters" type="millimeters"/><xs:element name="tenths" type="tenths"/></xs:sequence></xs:complexType>
