This is my understanding:
ONTAP has very granular performance data as can be seen in a performance archive via an AutoSupport on Demand. That data is averaged (statistical mean) by ONTAP and then recorded as an hourly data point. On the weekend, the performance AutoSupport sends those hourly data points to NetApp. Those are then parsed and graphed by Active IQ Digital Advisor.
If you have additional questions, feel free to follow-up with them.
Brett Albertson