Line is shrinking on Line Chart when many values are included

[rcheskin]

I have a line chart with a Reference curve where the default view only shows the Reference curve.  Notice how the curve starts at 20 Hz:

 When I add in additional lines to the chart, my Reference curve shrinks!  Now it begins at ~23 Hz.

How can I prevent the line from shrinking like this?

PBIX file can be downloaded from link below:

Shrinking Line PBIX 

[v-deddai1-msft]

Hi @rcheskin ,

For a high-density visual, Power BI intelligently slices your data into high-resolution chunks, and then picks important points to represent each chunk. That process of slicing high-resolution data is specifically tuned to ensure that the resulting chart is visually indistinguishable from rendering all of the underlying data points, but much faster and more interactive.

You can learn more from https://docs.microsoft.com/en-gb/power-bi/create-reports/desktop-high-density-sampling

If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.

Best Regards,

Dedmon Dai

[rcheskin]

Hi @v-deddai1-msft , if you read my post then you would know the resulting chart is obviously visually different because the minimum value is no longer represented.

[v-deddai1-msft]

Hi @rcheskin ,

In my understanding, for a high-density visual, Power BI intelligently slices your data into high-resolution chunks, and then picks important points to represent each chunk. The points picks in your situation is not the minium value. So it didn't show any more.  It should be the default for Power BI, I didn't find any option for it.

Best Regards,

Dedmon Dai

[rcheskin]

@v-deddai1-msft It is the minimum value for the x-axis (20 Hz), not literally the minimum for the "Values" in the Power BI Line Chart.

[parry2k]

@rcheskin at least we know the reason but I don't know the fix. I guess it is good to open a support case or put this on the ideas forum. Not a very common use case but something worth talking about with the support. Not sure what else to say or tell.

[rcheskin]

@parry2k Yeah I'll open a support ticket and then report back here.  Not sure what to put on the ideas forum until I better understand how the sampling functions.

[parry2k]

@rcheskin The problem is with the large data points, when you select multiple values from the slicer like brand 1 and brand 2, you will see an icon like i on the visual, and that explains it is showing sample data points and in that case, the starting point for reference line is getting removed. You can check that by clicking the show as a table as shown in the image below, and you will see in the table when multiple brands are selected the data point for 20hz for the reference line disappears. I hope it helps.

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[rcheskin]

Thanks for the insight - are there any workarounds other than modifying the underlying data for the Reference Curve?  When I eyeball the table data, the Reference has significantly fewer data points compared to the other products, so it appears the sampling is favoring the other lines.  I also find it strange that the sampling algorithm does not include the minium values in the data set by default.