6 Replies Latest reply on Oct 24, 2016 11:50 AM by mark.welsh

Diagonal Reference Lines with Running Total

Darren Lewis Aug 4, 2016 8:17 AM

Hello Experts,

I seem to be stumped (not difficult to do I'm afraid). I've scoured the interwebs, community forms and blogs and learned how to create a diagonal "reference" line from a duel axis trend line (one source: The Datographer: Creating a 45 Degree Reference Line in a Tableau Scatter Plot (without SQL!) ) . That part works. I am stumped on why it is inconsistently working with measures using running total. I am using the superstore data and 3 of the 4 measures in the orders table work just fine when i have running total.

But when i turn sales into a running total, my diagonal reference trend line disappears. Note the dashed dark gray line is gone in the second image.

I've attached the workbook. Any advice or direction would be appreciated.

diagonal reference line with table calcs issue.twbx 361.4 KB

1. Re: Diagonal Reference Lines with Running Total

Vincent Baumel Aug 4, 2016 9:31 AM (in response to Darren Lewis)

The line is still there, it's just not as big and bold as in the first image. The "No Measure Value" gray is what's The running sum of sales is a much higher value than the other running sums, so it flattens the others out quite a bit. This makes their confidence bands more narrow (since the trend is much more predictable and therefore can afford a narrower confidence band), and that might be why it looks a bit different in the second image. You could change the color being assigned to your 45 degree line to something a bit more offset, to make it stand out more.
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2. Re: Diagonal Reference Lines with Running Total

Darren Lewis Aug 4, 2016 9:44 AM (in response to Vincent Baumel)

Hello Vincent,

Thank you for taking the time to look at this. The line is there in the second image, true, however it is not a trend line. The trend line for the "No Measure Value" disappears when Running Total is turned on for Sales. That is what is what I can't figure.

Thanks again,
Darren
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3. Re: Diagonal Reference Lines with Running Total

Vincent Baumel Aug 4, 2016 10:14 AM (in response to Darren Lewis)

Here's where the weirdness comes into play. The trend line is there, but you can't see it unless you select some data points:

In the Trend Lines Options, you have selected "Show recalculated line for highlighted or selected data points". I think what's happening is that when no data points are selected, there technically is no trend - it's a constant ratio of x-value to y-value. When you select data points, however, it forces a calculation. This could explain why the trend line ONLY shows up when you select data points. I know it doesn't answer how to get a 45 degree reference line on there, but it's a step in that direction!
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4. Re: Diagonal Reference Lines with Running Total

Darren Lewis Aug 4, 2016 11:50 AM (in response to Vincent Baumel)

Hi Vincent,

Ya, I see that when I select points on the diagonal line, the trend line appears. Still can't figure out why the trend line disappears when I turn on Running Total for Sum of Sales.

Thanks again,
Darren
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5. Re: Diagonal Reference Lines with Running Total

Darren Lewis Aug 5, 2016 1:13 PM (in response to Darren Lewis)

Bump. Still hoping for a better understanding of why adding Running Total to Sales kills the Trend line.
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6. Re: Diagonal Reference Lines with Running Total

mark.welsh Oct 24, 2016 11:50 AM (in response to Darren Lewis)

I'm experiencing a somewhat similar scenario where adding a running sum causes changes to my reference line. Here's to hoping for a solution.

Window Sum calc causes change in Reference Line
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