var scatterPlot = ScatterPlot();

scatterPlot
  .outerWidth(960)
  .outerHeight(500)
  .margin({ left: 95, top: 5, right: 10, bottom: 85 })
  .xColumn("sepal_length")
  .xAxisLabel("Sepal Length (cm)")
  .xAxisLabelOffset(70)
  .xTicks(20)
  .yColumn("petal_length")
  .yAxisLabel("Petal Length (cm)")
  .yAxisLabelOffset(50)
  .yTicks(20)
  .colorColumn("species")
  .rColumn("sepal_width")// "r" stands for radius
  .rMin(2)
  .rMax(13)
  .colorRange(["#00c65c", "#8400c6", "#e54100"]);

function type(d){
  d.sepal_length = +d.sepal_length;
  d.sepal_width  = +d.sepal_width;
  d.petal_length = +d.petal_length;
  d.petal_width  = +d.petal_width;
  return d;
}

d3.csv("iris.csv", type, function (data){
  d3.select("#chart")
    .datum(data)
    .call(scatterPlot);
});