Custom Vertical Line using Plotly.js

Question

My Requirement is to draw vertical lines on certain dates of X Axis using Plotly.js. I am new to plotly and i managed to find an option to draw vertical line using 'Shapes' Option.

shapes: [{
  type: 'line',
  x0: '2000-01-11',
  y0: 0,
  x1: '2000-01-11',
  y1: 7,
  line: {
    color: 'grey',
    width: 1.5,
    dash: 'dot'
  }
}]

But the major difficulty i am facing is how to define Y Axis Values when drawing Vertical Line as Y Axis Scale will differ based on Data. I wanted it to be dynamic Something like y0: 0 ; y1: (height-margin.top-margin.bottom) in d3 which we use to draw a vertical line.

Please Help and the code is here http://codepen.io/anon/pen/VpwWmV?editors=0010#0

Answer 1

There are a couple of possibilities which could work for you:

• Use yref: paper to become independent of the y-axis scale (all values are normalized to be between 0 and 1)

• Always draw to the maximum resp. minimum y-value

  y1: Math.min(...trace1.y),
  

• Take the y-value of the corresponding x-value

  y1: trace1.y[trace1.x.indexOf('2000-01-02')],
  

All 3 ways are implemented below.

var trace1 = {
  x: ['2000-01-01', '2000-01-02', '2000-01-03', '2000-01-04', '2000-01-05', '2000-01-06', '2000-01-07', '2000-01-08', '2000-01-09', '2000-01-10', '2000-01-11', '2000-01-12', '2000-01-13', '2000-01-14', '2000-01-15', '2000-01-16', '2000-01-17', '2000-01-18', '2000-01-19', '2000-01-20', '2000-01-21', '2000-01-22', '2000-01-23', '2000-01-24', '2000-01-25', '2000-01-26', '2000-01-27', '2000-01-28', '2000-01-29', '2000-01-30', '2000-01-31'],
  y: [4.3, 8.2, 4.1, 5.6, -3, -0.2, 0.3, 0.4, 4.1, 5, 4.6, -0.2, -8.5, -9.1, -2.7, -2.7, -17, -11.3, -5.5, -6.5, -16.9, -12, -6.1, -6.6, -7.9, -10.8, -14.8, -11, -4.4, -1.3, -1.1],
  mode: 'lines',
  type: 'scatter',
  name: '2000'
};

var data = [trace1];

var layout = {
  xaxis: {
    type: 'date',
    title: 'January Weather'
  },
  yaxis: {
    title: 'Daily Mean Temperature'
  },
  shapes: [{
    type: 'line',
    x0: '2000-01-11',
    y0: 0,
    x1: '2000-01-11',
    yref: 'paper',
    y1: 1,
    line: {
      color: 'grey',
      width: 1.5,
      dash: 'dot'
    }
  }, {
    type: 'line',
    x0: '2000-01-17',
    y0: 0,
    x1: '2000-01-17',
    y1: Math.min(...trace1.y),
    line: {
      color: 'grey',
      width: 1.5,
      dash: 'dot'
    }
  }, {
    type: 'line',
    x0: '2000-01-02',
    y0: 0,
    x1: '2000-01-02',
    y1: trace1.y[trace1.x.indexOf('2000-01-02')],
    line: {
      color: 'grey',
      width: 1.5,
      dash: 'dot'
    }
  }],
  title: '2000 Toronto January Weather'
};

Plotly.plot('myDiv', data, layout);

<script src="https://cdn.plot.ly/plotly-latest.min.js"></script>

<div id="myDiv" style="width:100%;height:400px;"></div>