How to add a shape on a chart node in d3.js?

Question

I have a d3js area chart. On each data point/node I would like to add a custom svg shape.

How can I do this in a straightforward way and still within the idioms of d3.js coding?

This picture shows red circles, being the shapes I would like to add to my chart.

Answer 1

I hope this helps.

// Set the dimensions of the canvas / graph
var margin = {
    top: 30,
    right: 20,
    bottom: 30,
    left: 50
  },
  width = 600 - margin.left - margin.right,
  height = 270 - margin.top - margin.bottom;

// Parse the date / time
var parseDate = d3.time.format("%d-%b-%y").parse;

// Set the ranges
var x = d3.time.scale().range([0, width]);
var y = d3.scale.linear().range([height, 0]);

// Define the axes
var xAxis = d3.svg.axis().scale(x)
  .orient("bottom").ticks(5);

var yAxis = d3.svg.axis().scale(y)
  .orient("left").ticks(5);

// Define the line
var valueline = d3.svg.line()
  .x(function(d) {
    return x(d.date);
  })
  .y(function(d) {
    return y(d.close);
  });

// Adds the svg canvas
var svg = d3.select("body")
  .append("svg")
  .attr("width", width + margin.left + margin.right)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
  .attr("transform",
    "translate(" + margin.left + "," + margin.top + ")");

// Get the data
var data = [{
  "date": "1-May-12",
  "close": "58.13"
}, {
  "date": "30-Apr-12",
  "close": "53.98"
}, {
  "date": "27-Apr-12",
  "close": "67.00"
}, {
  "date": "26-Apr-12",
  "close": "89.70"
}, {
  "date": "25-Apr-12",
  "close": "99.00"
}, {
  "date": "24-Apr-12",
  "close": "130.28"
}];
data.forEach(function(d) {
  d.date = parseDate(d.date);
  d.close = +d.close;
});

// Scale the range of the data
x.domain(d3.extent(data, function(d) {
  return d.date;
}));
y.domain([0, d3.max(data, function(d) {
  return d.close;
})]);

// Add the valueline path.
svg.append("path")
  .attr("class", "line")
  .attr("d", valueline(data));

svg.selectAll('circle')
  .data(data)
  .enter().append('circle')
  .attr('cx', function(d) {
    return x(d.date);
  })
  .attr('cy', function(d) {
    return y(d.close);
  })
  .attr('r', 6);


// Add the X Axis
svg.append("g")
  .attr("class", "x axis")
  .attr("transform", "translate(0," + height + ")")
  .call(xAxis);

// Add the Y Axis
svg.append("g")
  .attr("class", "y axis")
  .call(yAxis);

body {
  font: 12px Arial;
}
path {
  stroke: steelblue;
  stroke-width: 2;
  fill: none;
}
.axis path,
.axis line {
  fill: none;
  stroke: grey;
  stroke-width: 1;
  shape-rendering: crispEdges;
}

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

Replace the circle part of the code with the below code to render rectangles as shape svg.selectAll('rect') .data(data) .enter().append('rect') .attr('x', function (d) { return x(d.date)-5;}) .attr('y', function (d) { return y(d.close)-5; }) .attr('width', 10) .attr('height', 10);