Forum Discussion
need help understanding Sankey Chart tooltip
I was not aware that the set of source values doesn't usually match the set of destination values in Sankey charts. However, in my work, those two sets will be identical, and, even though I can distinguish them with suffixes as you described, my customers don't want them distinguishable. In other words, my paths will always be circular So, I need to understand how Power BI is calculating these values for circular paths. My measure is simply the sum of Value. For the non-circular scenario (i.e., when I distinguish my Source and Destination values with suffixes as you described), the values that I expect to see in the tooltip when hovering over the bar segments on both sides of the chart (i.e., the sum of Value) match what Power BI displays. However, for the circular scenario, the expected values do not match what Power BI displays (for all except one). Below is a comparison of my expected value computations against what Power BI displays:
Again, how is Power BI arriving at the values that it's displaying for this scenario?
Note that Power BI's implementation of a Sankey is pretty weak. For a more complete (and much scarier) solution you want to use