private Set<String> getNeededVariablesForProjection() {
        final Set<String> projectionVars = new HashSet<>();

        final ImmutableTriple<FormulaEditText, FormulaEditText, TextSpinner<DistanceUnit>> fields = getFieldsForProjectionType();
        if (fields.left != null) {
            fields.left.addNeededVariables(projectionVars);
        }
        if (fields.middle != null) {
            fields.middle.addNeededVariables(projectionVars);
        }

        return projectionVars;
    }
State the Coordinate Calculator was last left in.
main/src/main/java/cgeo/geocaching/EditWaypointActivity.java