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Outlier slows down zooming in scattergl #6174
Description
I have large data sets, which have a fat tail, i.e. looks like having an outlier.
I use scattergl aiming for fast zooming. As shown in https://plotly.com/javascript/webgl-vs-svg
or in the example below, one million points can be done. However, if one point is set as an outlier, then zooming becomes very
slow. I don't understand this, and spent quite some time to pin down the problem.
<!DOCTYPE html>
<html>
<div id="plotly-div1"></div>
<div id="plotly-div2"></div>
<script src='https://cdn.plot.ly/plotly-latest.min.js'></script>
<script>
function gaussianRand() {
var rand = 0
for (var i=0; i < 3; ++i) {
rand += Math.random()
}
return (rand / 3) - 0.5
}
function plot(y, divnum){
trace1 = {
type: "scattergl",
y: y,
}
layout = {
height: 250,
margin: {l: 40, r: 10, b: 30, t: 10}
}
Plotly.plot('plotly-div'+divnum, {
data: [trace1],
layout: layout,
})
}
Y = []
for (var i=0; i < 1000000; i++) {
Y.push(gaussianRand())
}
plot(Y, 1)
Y[800000] = 100. // adding an outlier slows down zoom
plot(Y, 2)
delete Y
</script>
</html>Reacted by Callum Morris
Activity
alexcjohnson commentedon May 3, 2022
Thanks for digging in to this @mzechmeister - I suspect this case is problematic for our clustering algorithm for hover
plotly.js/src/traces/scattergl/calc.js
Line 78 in 042742d
mzechmeister commentedon May 4, 2022
Thanks for looking into the issue and the hover hint.
When setting
hovermode: falseinlayout, then the zoom speed feels similar both cases. That helps for now.CallumNZ commentedon Feb 21, 2023
I'm running into a similar problem. Some examples from one data set:
Range: 04-Feb to 21-Feb
Points: 103066
Lag on zoom? YES
Range: 04-Feb to 21-Feb, removing points from the middle that were outliers/not showing the same wave pattern.
Points: 85165
Lag on zoom? YES
Range: 06-Feb to 21-Feb
Points: 91866
Lag on zoom? NO
Range: 01-Feb to 17-Feb
Points: 97920
Lag on zoom? NO
Range: 01-Feb to 18-Feb
Points: 103680
Lag on zoom? YES
Setting
hover mode: falseas a workaround works as mentioned above.