Atlantic Supply Chain Blog

Gantt Chart Pivoting

The Gantt Chart was invented by Henry Gantt in 1910 to help manufacturing plants schedule their operations. With the advent of computerized scheduling systems, users can now manage their schedules using computerized Gantt charts. Atlantic Supply Chain of course provides a Gantt chart (aka Schedule Board), as shown below:



Each row corresponds to a facility (machine, reactor, processing unit) and each rectangle represents an activity that the facility is performing. The label on the activity indicates the operation being performed, with the activity color corresponding to the operation being performed. Users can add, delete, edit, drag and drop activities, run a variety of scheduling algorithms, and see the effects of those changes on a schedule. 


Schedules are, by definition, complex, multi-dimensional systems. The interactions among demand, capacity constraints, operations that facilities can perform, product differences, operating hours are what makes scheduling so hard. Even with the powerful algorithms provided by Atlantic, schedulers need to explore schedules from a variety of perspectives. Atlantic Supply Chain introduces a pivotable  Gantt chart that allows users to view a schedule from multiple dimensions.


Inspired by Microsoft Excel’s Pivot Tables, which allows users to view multi-dimensional data in a variety of ways, we allow the user to show a schedule in a variety of different ways.


For example, a scheduler might want to see exactly when different operations are being performed, independent of the facility on which the operations are being performed. Here’s that view for this schedule:



Each row now corresponds to an operation, and the labels on each activity correspond to the facility on which the operation is running. Similarly, the color for the activity now corresponds to the facility. Note that activities in this view can properly overlap, since a given operation may be performed simultaneously on more than one facility. The schedule board adjusts the height of the row to show both activities simultaneously.


In Atlantic Supply Chain, the user can see both of these views and manipulate the schedule from either view, with changes updated in the other view.


Pivoting, however, can do a lot more.  For example, consider the following view. This shows the schedule grouped by facility, but within a facility, there is a separate row shown for each operation that is being run on the facility.



Virtually any dimension associated with an activity can be used to define a row in the gantt chart. For example, operations consume and produce materials to and from different locations. Here’s a view that shows, by facility, the locations touched by the facility and the activities associated with those upstream and downstream locations:



This view of the schedule now suggests a convenient way to edit the schedule. To change the upstream or downstream location for a given activity, the scheduler simply can drag the activity from one row, say with upstream location WHSE1 to a row with upstream location WHSE2.


Perhaps the most powerful application of a pivotable Gantt chart is in viewing and editing multiple schedules. Atlantic Supply Chain allows schedulers (yes, more than one) to edit more than one schedule at a time.  For example, if two schedulers have divided responsibility for scheduling among different collections of facilities, each can work simultaneously on the same schedule (seeing the changes made by the other in real time), or they can work on copies of the schedule. At some point, though, the schedulers will need to merge their two schedules.  The pivotable Gantt chart treats schedule just like any other dimension (e.g., facility, operation, location). Here for example, is a pivotted view showing two schedules simultaneously, one on top of another.



Another view, however, is also useful, for each facility showing the schedule side by side, e.g.,:




Furthermore, users can drag activities from any row to any other row, for example, taking all the activities from REACTOR1 from TestSchedule to REACTOR1 in TestSchedule1, thereby merging parts of one schedule into another.


We are still learning new applications for pivoting as we work with our customers.

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