The Trees in Champaign by Number of Specimens (y axis) and Average Diameter (x axis)

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<html lang="en">
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		<meta charset="utf-8">
		<title>Trees in Champaign</title>
		<script type="text/javascript" src="https://d3js.org/d3.v3.min.js"></script>
		<style type="text/css">
			
			body {
				background-color: white;
				font-family: Helvetica, Arial, sans-serif;
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h1 {
				font-size: 24px;
				margin: 0;
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p {
				font-size: 14px;
				margin: 10px 0 0 0;
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svg {
				background-color: white;
			}

circle:hover {
				fill: orange;
			}
			
			.axis path,
			.axis line {
				fill: none;
				stroke: black;
				shape-rendering: crispEdges;
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			.axis text {
				font-family: sans-serif;
				font-size: 11px;
			}

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<h1>Trees of Champaign</h1>
<p>The trees owned by the city of Champaign, Illinois: number of specimens (x-axis) and average diameter (y-axis). <br>Data source: <a href="https://data.illinois.gov/Municipality/Trees-Owned-by-the-City-of-Champaign/dzge-uybj">data.illinois.gov</a></p>

var w = 700;
			var h = 600;
			var padding = [ 20, 10, 50, 50 ];  //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");

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

d3.csv("Champaign-trees-diam-totals.csv", function(data) {

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

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

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

circles.attr("cx", function(d) {
						return xScale(d.avgDiameter);
					})
					.attr("cy", function(d) {
						return yScale(d.totalSpecimens);
					})
					.attr("r", 4)
					.attr("fill", "steelblue")
					.append("title")
					.text(function(d) {
						if (d.commonName.indexOf(", ") != -1) {
							return "Champaign has " + d.totalSpecimens + " " + d.commonName.replace(", "," (") + ") trees with an average diameter of " + Math.round(d.avgDiameter) + " feet. ";
						} else {
							return "Champaign has " + d.totalSpecimens + " " + d.commonName + " trees with an average diameter of " + Math.round(d.avgDiameter) + " feet. ";
						}
					});

svg.append("g")
					.attr("class", "x axis")
					.attr("transform", "translate(0," + (h - padding[2] + 10) + ")")
					.call(xAxis);

svg.append("g")
					.attr("class", "y axis")
					.attr("transform", "translate(" + (padding[3] - 10) + ",0)")
					.call(yAxis);

});

</script>

</body>
</html>

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

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