Use this property to divide the scale by major ticks in a specified interval. If this property is not set, major ticks are arranged automatically.
In the case of a numeric scale, assign a numeric value to this property. If the scale is of the date-time type, assign one of the predefined string values. To set an interval to several days, hours, etc., assign an object with the corresponding field specified (days, hours or another field). Note that this object should contain only one of the fields described in this section.