Woods and trees and all that. My final submission for Exercise 5

<!DOCTYPE html>
<html lang="en">
	<head>
		<meta charset="utf-8">
		<title>Exercise 5</title>
		<script type="text/javascript" src="https://d3js.org/d3.v3.js"></script>
		<style type="text/css">
			
			body {
				background-color: white;
				font-family: Helvetica, Arial, sans-serif;
			}

h1 {
				font-size: 24px;
				margin: 0;
			}

p {
				font-size: 14px;
				margin: 10px 0 0 0;
			}

svg {
				background-color: white;
			}

circle:hover {
				fill: orange;
			}

.axis path,
            .axis line {
            	fill: none;
            	stroke: black;
            	shape-rendering: crispEdges;
            }

.axis text {
            	font-family: sans-serif;
            	font-size: 11px;
            }
	    
		</style>
	</head>
	<body>

<h1>RSPB Big Garden Bird Watch Results 2015</h1>
		<p>The Royal Society for the Protection of Birds (RSPB) is a conservation charity based in the UK.</p>
		<p>The Big Garden Bird Watch is the world's biggest citizen based wildlife survey.</p>
		<p>Over the course of one weekend over half a million people spent an hour observing the number and different types of bird species in their backgarden.</p>
		<p>This scatter plot shows the mean number of species spotted at any one time against the percentage of gardens in which they were spotted in.</p> 
		<p>Source: <a = href="https://www.rspb.org.uk/discoverandenjoynature/discoverandlearn/birdwatch/results.aspx">RSPB</a>, 2015</p>

var w = 500;
			var h = 500;
			var padding = [ 30, 0, 30, 40 ]  //Top, right, bottom, left

var xScale = d3.scale.linear()
								.range([ padding[3], w - padding[1] - padding[3] ]);

var yScale = d3.scale.linear()
								.range([ padding[0], h - padding[2] ]);

var xAxis = d3.svg.axis()
							.scale(xScale)
							.orient("bottom");

var yAxis = d3.svg.axis()
							.scale(yScale)
							.orient("left")
							.tickFormat(function(d){
								return d + "%";
							});

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

d3.csv("RSPB_BigGardenBirdWatch_UK_2015.csv", function(data) {

data.sort(function(a, b) {
					return d3.descending(+a.Percentage_Gardens, +b.Percentage_Gardens);
				});

xScale.domain([ 
					d3.min(data, function(d) {
					return +d.Mean;	
					}), 
					d3.max(data, function(d) {
					return +d.Mean;	
					}) 
				]);

yScale.domain([ 
					d3.max(data, function(d) {
						return +d.Percentage_Gardens;	
					}),
					d3.min(data, function(d) {
						return +d.Percentage_Gardens;	
					}),
				]);

var circles = svg.selectAll("circle")
								.data(data)
								.enter()
								.append("circle");

circles.attr("cx", function(d) {
						return xScale(d.Mean);
					})
					.attr("cy", function(d) {
						return yScale(d.Percentage_Gardens);
					})
					.attr("r", 5)
					.attr("fill", "steelblue")
					.append("title")
					.text(function(d) {
						return "A mean number of " + d.Mean + " " +d.Species+ "'s were spotted in " + d.Percentage_Gardens + "% of gardens.";
					});

svg.append("g")
					.attr("class", "x axis")
					.attr("transform", "translate(0," + (h - padding[2]) + ")")
					.call(xAxis);

svg.append("g")
					.attr("class", "y axis")
					.attr("transform", "translate(" + padding[3] + ",0)")
					.call(yAxis);

});

</script>

</body>
</html>

Modified http://d3js.org/d3.v3.js to a secure url

https://d3js.org/d3.v3.js