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Mark_Porter's avatar
Mark_Porter
Copper Contributor
Jan 18, 2022

What is the Chart Axis Bounds Calculation when set to Automatic?

Hi All, 

 

Does anyone happen to know what formula is used by the developers for calculating Chart Axis Minimum, and Maximum, bounds when they are set to Auto (Ref Figure 1 below)? 

Once this is known a scatter graph can be created whereby a primary & secondary axis can be 
even where negative values exist (Ref Figure 2 below)

 

figure 1

 

 

figure 2

 

The below link is all I could find whilst researching the subject however it doesn't appear to be correct 

https://peltiertech.com/how-excel-calculates-automatic-chart-axis-limits/

 

Thanks in advance for your help 

Cheers 

Mark

Charting
developer
excel

1 Reply

  • Mark_Porter's avatar
    Mark_Porter
    Copper Contributor
    Jan 20, 2022

    So, since my last post  I've created a column chart with a single record, then used vba to create a dataset from 0 to 100, in 0.01 increments, and logged the chart's "MaximumScale" bounds that are automatically created for the vertical axis as a list of records.

    I've then graphed these outputs (Ref: figure 3 below) to try to determine the algorithm used by Microsoft to automatically adjust the vertical axis. 

    If anyone knows of an easy way to reverse engineer this dataset your help would be greatly appreciated. 

    figure 3

    TIA 

    Mark Porter 

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