# Interface Formula

All Known Implementing Classes:
  `DefaultFormula`

@UML(identifier="CC_Formula", specification=ISO_19111) public interface Formula
Specification of the coordinate operation method formula.

Since:
  2.3

- ## Method Summary

  Modifier and Type
  Method
  Description
  `Citation`
  `getCitation()`
  Reference to a publication giving the formula(s) or procedure used by the coordinate operation method.
  `InternationalString`
  `getFormula()`
  Formula(s) or procedure used by the operation method.

- ## Method Details

  - ### getFormula

    @UML(identifier="formula", obligation=CONDITIONAL, specification=ISO_19111) InternationalString getFormula()
    Formula(s) or procedure used by the operation method.
    Returns:
      The formula used by the operation method, or `null` if none.

  - ### getCitation

    @UML(identifier="formulaCitation", obligation=CONDITIONAL, specification=ISO_19111) Citation getCitation()
    Reference to a publication giving the formula(s) or procedure used by the coordinate operation method.
    Returns:
      Reference to a publication giving the formula, or `null` if none.