trivariate scatterplot d3

<!DOCTYPE html>
<html lang = "en">
	<head>
		<meta charset="utf-8">
		<title>A scatterplot comparing population and disease count colored by disease</title>
		<script src = "https://d3js.org/d3.v4.min.js"></script>
		<style type="text/css">
		</style>
	</head>
	<body>
		<h3> Trivariate Scatterplot of Population vs Number of Reported Diseases </h3>
		<script type = "text/javascript">
			//Width and height"
			var w = 700;
			var h = 500;
			var padding = 75;

var xScale = d3.scaleLinear();

var yScale = d3.scaleLinear();

var xAxis = d3.axisBottom()
							.scale(xScale)
							.ticks(7);

var yAxis = d3.axisLeft()
							.scale(yScale)
							.ticks(7);

//Create SVG element
			var svg = d3.select("body")
						.append("svg")
						.attr("width",w)
						.attr("height",h);

var color = d3.scaleOrdinal(d3.schemeCategory10); //use ordinal color scale to assign each disease a color

//converts the data to integers
			var rowConverter = function(d) {
	
				return {
					disease : d.disease,
					number: parseInt(d.number),
					population: parseInt(d.population)
				}
			}

d3.csv("health.csv", rowConverter, function(data) {
				dataset = data;

svg.append("g") 
					.attr("class", "axis") 
					.attr("transform", "translate(0," + (h-padding) + ")") 
					.call(xAxis);

svg.append("g")
					.attr("class", "axis")
					.attr("transform", "translate(" + padding + ",0)")
					.call(yAxis);

var legend = svg.append("g")
  								.attr("class", "legend")
  								.attr("x", w - 200)
  								.attr("y", 30)
  								.attr("height", 10)
  								.attr("width", 10);

legend.selectAll("rect")
  						.data(diseases)
  						.enter()
  						.append("rect")
  						.attr("x", w-200)
  						.attr("y", function(d,i) {
  							return i*20;
  						})
  						.attr("height", 10)
  						.attr("width", 10)
  						.attr("fill", function(d) {
  							return color(d);
  						});

legend.selectAll("text")
  						.data(diseases)
  						.enter()
  						.append("text")
			   			.text(function(d) {
			   				console.log(d);
			   				return d;
			   			})
			   			//.attr("text-anchor", "middle")
  						.attr("x", w-180)
  						.attr("y", function(d,i) {
  							return i*20 + 10;
  						})
  						.attr("font-family", "sans-serif")
			   			.attr("font-size", "11px")
			   			.attr("fill", "black");

svg.append("text") 
					.attr("transform", "translate (" + 15 + "," + (h/2) + ") rotate(-90)")
					.attr("text-anchor", "middle")
      				.text("Disease Count")
      				.attr("fill", "black");

svg.append("text") 
					.attr("x", w/2 - 20)
					.attr("y", h - 10)
					.attr("text-anchor", "middle")
      				.text("Population")
      				.attr("fill", "black");

});

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