# Perspective PowerChart Data Compression

**URL:** <https://forum.inductiveautomation.com/t/perspective-powerchart-data-compression/69840>\
**Category:** Ignition\
**Tags:** perspective\
**Created:** [February 14, 2023, 4:40pm UTC](https://forum.inductiveautomation.com/t/perspective-powerchart-data-compression/69840 "2023-02-14T16:40:02Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![NJ\_enginerds](https://avatars.discourse-cdn.com/v4/letter/n/ea5d25/32.png) [@NJ\_enginerds](https://forum.inductiveautomation.com/u/NJ_enginerds)\
**Post date:** [February 14, 2023, 4:40pm UTC](https://forum.inductiveautomation.com/t/perspective-powerchart-data-compression/69840/1 "2023-02-14T16:40:02Z")

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For the perspective powerchart (running Ignition v8.1.17) is there a defined algorithm or set of rules on how data is compressed when displaying a trend? I'm especially interested in the algorithm's ability to show "important" parts in the trend, such as local max/min and not just the global max/mins.

Just as an example, for the snippet below, we can see data trended over 2 weeks. Given data logging settings for this PLC, this is \>1 million data points compressed into a chart with 500 points displayed. How can I be confident that there weren't any momentary blips/spikes in the data that aren't shown in the chart when we're reducing the data 2000-fold?

 ![image](https://us1.discourse-cdn.com/inductiveautomation/original/3X/4/c/4cf7e1a362640e765cb3a573bf167f9bd07beb3c.jpeg)