Outlier slows down zooming in scattergl

描述

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.

https://jsfiddle.net/fasmu943

<!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>

调研方向

首先运行链接的 JSFiddle 复现，并比较包含和不包含单个异常值时百万点 scattergl 数据的缩放效果。调查示例所涉及的 scattergl 缩放路径和 WebGL 行为。当存在一个异常值时缩放性能不再明显下降，即表示完成。

由索引模型根据 Issue 内容生成。

评估

技术栈

javascript

领域

data-visualization, performance

Issue 类型

缺陷

难度

4/5

预计耗时

3-5 天

活跃度

停滞

描述清晰度

基本清楚

新手友好度

35/100

描述

贡献指南

从这里开始

调研方向

评估

Outlier slows down zooming in scattergl

描述

贡献指南

从这里开始

调研方向

评估

把新 issue 发到你的邮箱