Part of the video course: D3.js in Motion.
An example scatter plot with color legend using D3 and d3-legend.
This shows the "Iris" dataset. Originally published at UCI Machine Learning Repository: Iris Data Set, this small dataset from 1936 is often used for testing out machine learning algorithms and visualizations. Each row of the table represents an iris flower, including its species and dimensions of its botanical parts, sepal and petal, in centimeters.
xxxxxxxxxx<html> <head> <meta charset="utf-8"> <meta name="viewport" content="width=device-width"> <script src="https://d3js.org/d3.v4.min.js"></script> <script src="https://cdnjs.cloudflare.com/ajax/libs/d3-legend/2.24.0/d3-legend.min.js"></script> <title>Basic Scatter Plot</title> <style> body { margin: 0px; } .domain { display: none; } .tick line { stroke: #C0C0BB; } .tick text, .legendCells text { fill: #8E8883; font-size: 28pt; font-family: sans-serif; } .axis-label, .legend-label { fill: #635F5D; font-size: 50pt; font-family: sans-serif; } </style> </head> <body> <svg width="960" height="500"></svg> <script> const xValue = d => d.sepalLength; const xLabel = 'Sepal Length'; const yValue = d => d.petalLength; const yLabel = 'Petal Length'; const colorValue = d => d.species; const colorLabel = 'Species'; const margin = { left: 120, right: 300, top: 20, bottom: 120 }; const svg = d3.select('svg'); const width = svg.attr('width'); const height = svg.attr('height'); const innerWidth = width - margin.left - margin.right; const innerHeight = height - margin.top - margin.bottom; const g = svg.append('g') .attr('transform', `translate(${margin.left},${margin.top})`); const xAxisG = g.append('g') .attr('transform', `translate(0, ${innerHeight})`); const yAxisG = g.append('g'); const colorLegendG = g.append('g') .attr('transform', `translate(${innerWidth + 60}, 150)`); xAxisG.append('text') .attr('class', 'axis-label') .attr('x', innerWidth / 2) .attr('y', 100) .text(xLabel); yAxisG.append('text') .attr('class', 'axis-label') .attr('x', -innerHeight / 2) .attr('y', -60) .attr('transform', `rotate(-90)`) .style('text-anchor', 'middle') .text(yLabel); colorLegendG.append('text') .attr('class', 'legend-label') .attr('x', -30) .attr('y', -40) .text(colorLabel); const xScale = d3.scaleLinear(); const yScale = d3.scaleLinear(); const colorScale = d3.scaleOrdinal() .range(d3.schemeCategory10); const xAxis = d3.axisBottom() .scale(xScale) .tickPadding(15) .tickSize(-innerHeight); const yAxis = d3.axisLeft() .scale(yScale) .ticks(5) .tickPadding(15) .tickSize(-innerWidth); const colorLegend = d3.legendColor() .scale(colorScale) .shape('circle'); const row = d => { d.petalLength = +d.petalLength; d.petalWidth = +d.petalWidth; d.sepalLength = +d.sepalLength; d.sepalWidth = +d.sepalWidth; return d; }; d3.csv('iris.csv', row, data => { xScale .domain(d3.extent(data, xValue)) .range([0, innerWidth]) .nice(); yScale .domain(d3.extent(data, yValue)) .range([innerHeight, 0]) .nice(); g.selectAll('circle').data(data) .enter().append('circle') .attr('cx', d => xScale(xValue(d))) .attr('cy', d => yScale(yValue(d))) .attr('fill', d => colorScale(colorValue(d))) .attr('fill-opacity', 0.6) .attr('r', 8); xAxisG.call(xAxis); yAxisG.call(yAxis); colorLegendG.call(colorLegend) .selectAll('.cell text') .attr('dy', '0.1em'); }); </script> </body></html> https://d3js.org/d3.v4.min.js
https://cdnjs.cloudflare.com/ajax/libs/d3-legend/2.24.0/d3-legend.min.js