Dim StartPoint1, StartPoint2, EndPoint1, EndPoint2 As String

StartPoint1 = Application.Evaluate("=ADDRESS(1,MATCH(TRUE,4:4<>0,0))")
EndPoint1 = Application.Evaluate("=ADDRESS(1,MAX((4:4>0)*COLUMN(4:4)))")

StartPoint2 = Application.Evaluate("=ADDRESS(4,MATCH(TRUE,4:4<>0,0))")
EndPoint2 = Application.Evaluate("=ADDRESS(4,MAX((4:4>0)*COLUMN(4:4)))")

ActiveChart.SetSourceData Source:=Union(Sheets(SheetName).Range(StartPoint1 & ":" & EndPoint1), Sheets(SheetName).Range(StartPoint2 & ":" & EndPoint2))