# Vision Easy Chart Pen Display and Aggregation

**URL:** <https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723>\
**Category:** Ignition\
**Tags:** vision\
**Created:** [September 27, 2023, 3:33pm UTC](https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723 "2023-09-27T15:33:12Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![MCC](https://avatars.discourse-cdn.com/v4/letter/m/3e96dc/32.png) [@MCC](https://forum.inductiveautomation.com/u/MCC)\
**Post date:** [September 27, 2023, 3:33pm UTC](https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723/1 "2023-09-27T15:33:12Z")

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Hi all,

A customer asked me a detailed question for which I don't have an answer. Apologies if this is already answered but my searches of the forum didn't find it.

How does an Easy Chart draw the trend line when Min/Max aggregation is selected? It can only draw one point per pen per timestamp but the dataset has two rows for each time. Does it use the mean between the two values to calculate the position of the point on the y-axis?

Thanks for your thoughts!

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**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [September 27, 2023, 8:36pm UTC](https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723/2 "2023-09-27T20:36:36Z")

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I don't think it aggregates on the pen. I picked a historical tag and made a few pens with different aggregates: Closest, MinMax, Min, Max. In all instances, it uses the raw value.

Then I added min and max _calculated_ pens, which drew lines for the data in view.  
 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/d/1/d1b5198abd86be2495942e9bfa7b53e252c0b8e2.png)

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<div class="post-metadata">

**Author:** ![MCC](https://avatars.discourse-cdn.com/v4/letter/m/3e96dc/32.png) [@MCC](https://forum.inductiveautomation.com/u/MCC)\
**Post date:** [September 27, 2023, 8:41pm UTC](https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723/3 "2023-09-27T20:41:06Z")

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Ah, so maybe it just aggregates when you click the disk icon to save chart data to Excel?

Thanks!

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**Author:** ![JordanCClark](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/jordancclark/32/83362_2.png) [@JordanCClark](https://forum.inductiveautomation.com/u/JordanCClark)\
**Post date:** [September 27, 2023, 8:45pm UTC](https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723/4 "2023-09-27T20:45:25Z")

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Not sure. The easy chart doesn't seem to have any way to enter a sample size to create a time slice to use for the aggregate. 🤷‍♂️

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**Author:** ![ccontreras](https://sea1.discourse-cdn.com/inductiveautomation/user_avatar/forum.inductiveautomation.com/ccontreras/32/40931_2.png) [@ccontreras](https://forum.inductiveautomation.com/u/ccontreras)\
**Post date:** [June 24, 2025, 3:23pm UTC](https://forum.inductiveautomation.com/t/vision-easy-chart-pen-display-and-aggregation/79723/5 "2025-06-24T15:23:22Z")

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The chart's resolution property does this. Default of 300. -1 does raw data queries with no aggregation.