Area chart bug

Elastic Stack Kibana
1

I used an Area chart to compute view of some kind of usage.
I have 26 lines, each one with a random max nb of tokens. I want to graph the overall nb of tokens at any one time.

I use an area chart, graph the min of the token amount per line. On the Y axis, I have the min of tokens, and have a X-axis Date Histogram, with an aggregation Split Area per line id.

As you can see on the attached graph, the Area Chart doesnt display what plotting individual lines shows.

Basically if there arent any log line in an intermediate bucket, the Area Chart sees them as Zeros, where the line chart carries over the last known value.

Pasted image770×832 126 KB

2

I am currently checking into this to understand if its really an issue. One thing that would help when comparing area charts with line charts is to remove the stacking from area charts. You can select the Chart Mode option "overlap" from the options menu in area charts.

3

Hi, I only provided the line chart to highlight the issue. This is really not a view I like in this case to be honest!

If you remove the stacking, then you cannot view the total amount of tokens at any one time.

You could get it, but you would then need to compute it into a new value. And this is not a route I want to go through unless I really have to.

4

Stacked area charts are zero filled so layers can be stacked properly. So if some values are missing in one stack layer but occur in another stack layer, then those values are substituted with zeros.

In line charts, there is no stacking, and hence no need to substitute values with zeros. The line simply interpolates between valid data points. We are working on adding a new feature to line charts that will break up lines on null values. So if certain data points have null values, the line stops at the last valid point and begins again at the next valid point. This will help in visualizing breaks between points on the line chart.

5

Hi,
thank you for the explanation.

"Stacked area charts are zero filled so layers can be stacked properly".
Why can't the data be interpolated between valid data points as for the line graphs?

I see use cases for both behaviour, the zero padding as well as the interpolation. It would be great to be able to configure these 2 behaviours.

6

Data can be interpolated between valid data points in area charts without injecting zeros, but not for stacked area charts. Due to the algorithm that is employed for creating stacked charts, zero injection is needed. However, for single area charts and for overlapping area charts, this is possible, and we are currently working on adding this functionality.