//version 1

	var margin = {top: 50, right: 20, bottom: 20, left: 50};
	var width = 450 - margin.right - margin.left;
	var height = width;

	////////////////////////////////////////////////

	////////////////////////////////////////////////
	// SET UP SCALES FOR  CHART
	////////////////////////////////////////////////

	var nest = d3.nest()
	.key(function(d) { return d.levelOfNeed; }).sortKeys(d3.ascending)
	.key(function(d) { return d.age; }).sortKeys(d3.ascending);

	var nested;
	var currentView = "costPerPerson";

	var colour = d3.scaleOrdinal()
		.range([siuColours.orange, siuColours.teal, siuColours.green10, siuColours.purple10]);

	var svg = d3.select("#treemap-chart").append("svg")
		.attr("width", width + margin.left + margin.right)
		.attr("height", height + margin.top + margin.bottom);

	var gTreemap = svg.append("g")
		.attr("class", "g-treemap")
		.attr("transform", "translate("+ margin.left + ","+ margin.top + ")" );

	var treemap = d3.treemap()
		.size([width , height])
    .padding(1)
    .round(true)
		.tile(d3.treemapSliceDice);

	d3.csv("data.csv", convertTextToNumbers, function(error, data) {
	  if (error) throw error;

		nested = nest.entries(data);

		var root = d3.hierarchy({values: nested}, function(d) { return d.values; })
				.sum(function(d) { return d[currentView]; })
				.sort(function(a, b) { return b.levelOfNeed - a.levelOfNeed; });

		treemap(root);

			var cell = gTreemap.selectAll(".g-cells")
		    .data(root.leaves())
		    .enter().append("g")
					.attr("class", "g-cells");

			cell.append("rect")
	      .attr("id", function(d) { return "rect-" + d.data.age + "-" +  d.data.levelOfNeed; })
					.style("fill", function(d) { return colour(d.data.age); } );


				changeChart(0);

	});

	function changeChart(transitionDuration) {

			if (currentView === "unit") {
				currentView = "totalCost";
			} else if ( currentView === "totalCost" ) {
				currentView = "costPerPerson";
			} else {
				currentView = "unit";
			};


			var root = d3.hierarchy({values: nested}, function(d) { return d.values; })
					.sum(function(d) { return d[currentView]; })
		  		.sort(function(a, b) { return b.levelOfNeed - a.levelOfNeed; });

			treemap(root);

			d3.selectAll(".g-cells")
			.data(root.leaves())
			.transition()
			.duration(transitionDuration)
			.attr("transform", function(d) { return "translate(" + d.y0 + "," + d.x0 + ")"; });  //switched the use of the x and y coordinates

			d3.selectAll("rect")
			.data(root.leaves())
			.transition()
			.duration(transitionDuration)
	    .attr("width", function(d) { return d.y1 - d.y0; })   // and the same here
	    .attr("height", function(d) { return d.x1 - d.x0; });  // and the same here

	}




function convertTextToNumbers(d) {
	d.totalCost = +d.totalCost;
	d.unit = +d.unit;
	d.costPerPerson = +d.costPerPerson;
  return d;
};