Defines a list of the most commonly-used units of linear measurement. These values can be used to create instances MeasurementUnit, as an alternative to using well-known IDs (WKIDs). In addition to the units in this enumeration, you can also use less commonly-used units, by passing a WKID of a linear unit to the inherited MeasurementUnit.fromWkid(Int) factory method. The function MeasurementUnit.wkid returns the WKID of the unit.
Indicates that the unit of linear measurement is a custom unit, or a unit that is not listed in the enumerated type. This value may be returned from an LinearUnit created from a WKID of a less commonly used unit of measurement that does not have an equivalent value in this enumeration.