learning to use color legend from d3.legend

This example demonstrates use of the d3-legend library.

The color scale comes from ColorBrewer.

forked from curran's block: Using d3-legend

<!DOCTYPE html>
<html>
  <head>
    <meta charset="utf-8">
    <title>Learning to use color legend from d3.legend</title>
    
    <script src="//cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/d3-legend/1.1.0/d3-legend.js"></script>
    <script src="colorbrewer.min.js"></script>
  </head>
  <body>
    <svg width="960" height="500"></svg>
    <script>
      var svg = d3.select("svg");

// Color legend.
      var colorScale = d3.scale.quantize()
        .domain([ 1, 10 ])
        .range(colorbrewer.Blues[9]);

var colorLegend = d3.legend.color()
        .labelFormat(d3.format(".0f"))
        .scale(colorScale)
        .shapePadding(5)
        .shapeWidth(50)
        .shapeHeight(20)
        .labelOffset(12);

svg.append("g")
        .attr("transform", "translate(352, 60)")
        .call(colorLegend);

var data = [3,8,5,2,8,9,2];

svg.selectAll('circle')
        .data(data)
        .enter()
        .append('circle')
      	.attr("r", function(d,i){return d * 2.5})
        .attr("cx", function(d,i){return i * 50 + 30})
        .attr("cy", 100)
        .attr("fill", function(d,i){return colorScale(d)});

</script>
  </body>
</html>

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js

https://cdnjs.cloudflare.com/ajax/libs/d3-legend/1.1.0/d3-legend.js