True if Microsoft Excel chooses appropriate base units for the specified category axis. The default value is True. Read/write Boolean.
Remarks
You cannot set this property for a value axis.
Example
This example sets the category axis in embedded chart one on worksheet one to use a time scale with automatic base units.
With Worksheets(1).ChartObjects(1).Chart
With .Axes(xlCategory)
.CategoryType = xlTimeScale
.BaseUnitIsAuto = True
End With
End With