This post describes how to build a connected scatter plot with d3.js. The chart includes tooltip, and curve smoothing. Learn more about the theory of connected scatter plot in data-to-viz.com. This example works with d3.js v4 and v6
.curve() function. See this post that is dedicated to it.<!DOCTYPE html>
<meta charset="utf-8">
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v4.js"></script>
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
<!-- Circle are black when hovered-->
<style>
.myCircle:hover {
stroke: black;
}
</style>
<!DOCTYPE html>
<meta charset="utf-8">
<!-- Load d3.js -->
<script src="https://d3js.org/d3.v6.js"></script>
<!-- Create a div where the graph will take place -->
<div id="my_dataviz"></div>
<script>
// set the dimensions and margins of the graph
var margin = {top: 10, right: 30, bottom: 30, left: 60},
width = 460 - margin.left - margin.right,
height = 400 - margin.top - margin.bottom;
// append the svg object to the body of the page
var svg = d3.select("#my_dataviz")
.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 + ")");
//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/connectedscatter.csv",
// When reading the csv, I must format variables:
function(d){
return { date : d3.timeParse("%Y-%m-%d")(d.date), value : d.value }
},
// Now I can use this dataset:
function(data) {
// Add X axis --> it is a date format
var x = d3.scaleTime()
.domain(d3.extent(data, function(d) { return d.date; }))
.range([ 0, width ]);
svg.append("g")
.attr("transform", "translate(0," + height + ")")
.call(d3.axisBottom(x));
// Add Y axis
var y = d3.scaleLinear()
.domain( [8000, 9200])
.range([ height, 0 ]);
svg.append("g")
.call(d3.axisLeft(y));
// Add the line
svg.append("path")
.datum(data)
.attr("fill", "none")
.attr("stroke", "black")
.attr("stroke-width", 1.5)
.attr("d", d3.line()
.curve(d3.curveBasis) // Just add that to have a curve instead of segments
.x(function(d) { return x(d.date) })
.y(function(d) { return y(d.value) })
)
// create a tooltip
var Tooltip = d3.select("#my_dataviz")
.append("div")
.style("opacity", 0)
.attr("class", "tooltip")
.style("background-color", "white")
.style("border", "solid")
.style("border-width", "2px")
.style("border-radius", "5px")
.style("padding", "5px")
// Three function that change the tooltip when user hover / move / leave a cell
var mouseover = function(d) {
Tooltip
.style("opacity", 1)
}
var mousemove = function(d) {
Tooltip
.html("Exact value: " + d.value)
.style("left", (d3.mouse(this)[0]+70) + "px")
.style("top", (d3.mouse(this)[1]) + "px")
}
var mouseleave = function(d) {
Tooltip
.style("opacity", 0)
}
// Add the points
svg
.append("g")
.selectAll("dot")
.data(data)
.enter()
.append("circle")
.attr("class", "myCircle")
.attr("cx", function(d) { return x(d.date) } )
.attr("cy", function(d) { return y(d.value) } )
.attr("r", 8)
.attr("stroke", "#69b3a2")
.attr("stroke-width", 3)
.attr("fill", "white")
.on("mouseover", mouseover)
.on("mousemove", mousemove)
.on("mouseleave", mouseleave)
})
</script> <script>
// set the dimensions and margins of the graph
const margin = {top: 10, right: 30, bottom: 30, left: 60},
width = 460 - margin.left - margin.right,
height = 400 - margin.top - margin.bottom;
// append the svg object to the body of the page
const svg = d3.select("#my_dataviz")
.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})`);
//Read the data
d3.csv("https://raw.githubusercontent.com/holtzy/D3-graph-gallery/master/DATA/connectedscatter.csv",
// When reading the csv, I must format variables:
d => {
return {date : d3.timeParse("%Y-%m-%d")(d.date), value : d.value}}).then(
// Now I can use this dataset:
function(data) {
// Add X axis --> it is a date format
const x = d3.scaleTime()
.domain(d3.extent(data, d => d.date))
.range([ 0, width ]);
svg.append("g")
.attr("transform", `translate(0, ${height})`)
.call(d3.axisBottom(x));
// Add Y axis
const y = d3.scaleLinear()
.domain( [8000, 9200])
.range([ height, 0 ]);
svg.append("g")
.call(d3.axisLeft(y));
// Add the line
svg.append("path")
.datum(data)
.attr("fill", "none")
.attr("stroke", "black")
.attr("stroke-width", 1.5)
.attr("d", d3.line()
.curve(d3.curveBasis) // Just add that to have a curve instead of segments
.x(d => x(d.date))
.y(d => y(d.value))
)
// create a tooltip
const Tooltip = d3.select("#my_dataviz")
.append("div")
.style("opacity", 0)
.attr("class", "tooltip")
.style("background-color", "white")
.style("border", "solid")
.style("border-width", "2px")
.style("border-radius", "5px")
.style("padding", "5px")
// Three function that change the tooltip when user hover / move / leave a cell
const mouseover = function(event,d) {
Tooltip
.style("opacity", 1)
}
const mousemove = function(event,d) {
Tooltip
.html("Exact value: " + d.value)
.style("left", `${event.layerX+10}px`)
.style("top", `${event.layerY}px`)
}
const mouseleave = function(event,d) {
Tooltip
.style("opacity", 0)
}
// Add the points
svg
.append("g")
.selectAll("dot")
.data(data)
.join("circle")
.attr("class", "myCircle")
.attr("cx", d => x(d.date))
.attr("cy", d => y(d.value))
.attr("r", 8)
.attr("stroke", "#69b3a2")
.attr("stroke-width", 3)
.attr("fill", "white")
.on("mouseover", mouseover)
.on("mousemove", mousemove)
.on("mouseleave", mouseleave)
})
</script>