Line-Chart rendering showing zeros for truncated data

[110]

Not sure if this is a feature or a bug -  but if a line chart is painted with its point/line count limited, where points are pruned from a chart, they're displayed as zeros .

For example I'm rendering a historical FX rate chart  - at first I had a heart attack as I thought we were missing data.

When I zoom in with the scroll wheel, they eventually paint up.

Ideally, even though the points may be being pruned, I'd expect the behaviour to be similar to below, where gaps were connected ( as set in 'Missing Values >  Show as connections ) 

If I can get my access to the Pendo.Io  login for the Ideation I'll post it there.

[nevopotokcloudinary]

You can usually fix this by making sure Qlik is returning nulls instead of zeros for those truncated points, and by telling the chart not to plot nulls.

In practice that means:

• Change the measure to return null() when the value is outside your desired range or shouldn’t be shown, e.g.

  If( [YourCondition], [YourMeasure], null() )

• In the line chart properties, under Presentation → Data handling, make sure options like “Include zero values” (or similar, depending on version) aren’t forcing a line down to 0 for missing points.

• If you’re using dimension limits or an aggr, double-check they’re not creating extra rows with 0 that Qlik then draws as real data.

That way the truncated data is truly “missing” (null), so the line doesn’t drop to zero on those points.

[110]

Thanks @nevopotokcloudinary  - that's indeed what I'd done, I can't seem to recreate the bug now.

The chart had the usual options set ( in terms of handling of zeros etc )  , there's no dimension logic or set-analysis to speak of, just a linear date dimension and a max(rate) for each currency over the date.

I'm able to get back into ideation now, so will post there. My suggestion would be, given an unknown sample size, that if scaling a chart, it'd look at something like standard deviation to sample points in range when painting the chart to the canvas , rather than using a fixed number of points/lines .

Much like how games use level of detail to cull triangles on a mesh based on distance, but still retain features/ silhouette.