plotEdge.js

// plot a histogram for the number of edges in public graphs, data in a .csv file
function parser1(d) {
    d.pMPG = +d.Edges;
    return d;
}

function mpghist1(csvdata) {
    var binsize = 10;
    var minbin = 0; 
    var maxofcsvdata = d3.max(csvdata, function(d){return d.pMPG;});
    var maxbin = Math.ceil(maxofcsvdata + 0.01 * maxofcsvdata);
    var numbins = Math.floor((maxbin - minbin) / binsize);

    // whitespace on either side of the bars
    var binmargin = .2; 
    var margin = {top: 10, right: 30, bottom: 50, left: 60};
    var width = 1050 - margin.left - margin.right;
    var height = 450 - margin.top - margin.bottom;

    // Set the limits of the x axis
    var xmin = minbin - 1;
    var xmax = maxbin + 1;

    histdata = new Array(numbins);
    for (var i = 0; i < numbins; i++) {
		histdata[i] = { numfill: 0, meta: "" };
	        }

    // Fill histdata with y-axis values and meta data
    csvdata.forEach(function(d) {
		var bin = Math.floor((d.pMPG - minbin) / binsize);
		if ((bin.toString() != "NaN") && (bin < histdata.length)) {
			histdata[bin].numfill += 1;
			histdata[bin].meta += "<tr><td>" + d.Name +
				" " +
				"</td><td>" + 
				d.pMPG.toFixed(0) + " edges</td></tr>";
		}
    });

    // This scale is for determining the widths of the histogram bars
    var x = d3.scale.linear()
	  .domain([0, (xmax - xmin)])
	  .range([0, width]);

    // Scale for the placement of the bars
    var x2 = d3.scale.linear()
	  .domain([xmin, xmax])
	  .range([0, width]);
	
    var y = d3.scale.linear()
	  .domain([0, d3.max(histdata, function(d) { 
	   return d.numfill; 
	   })])
	  .range([height, 0]);

    var xAxis = d3.svg.axis()
	  .scale(x2)
	  .orient("bottom");
    var yAxis = d3.svg.axis()
	  .scale(y)
	  .ticks(8)
	  .orient("left");

    var tip = d3.tip()
	  .attr('class', 'd3-tip')
	  .direction('e')
	  .offset([0, 20])
	  .html(function(d) {
	   return '<table id="tiptable">' + d.meta + "</table>";
	   });

    // put the graph in the "graphEdge" div
    var svg = d3.select("#graphEdge").append("svg")
	  .attr("width", width + margin.left + margin.right)
	  .attr("height", height + margin.top + margin.bottom)
	  .append("g")
	  .attr("transform", "translate(" + margin.left + "," + 
						margin.top + ")");

    svg.call(tip);

    // set up the bars
    var bar = svg.selectAll(".bar")
	  .data(histdata)
	  .enter().append("g")
	  .attr("class", "bar")
	  .attr("transform", function(d, i) { return "translate(" + 
	       x2(i * binsize + minbin) + "," + y(d.numfill) + ")"; })
	  .on('mouseover', tip.show)
	  .on('mouseout', tip.hide);

    // add rectangles of correct size at correct location
    bar.append("rect")
	  .attr("x", x(binmargin))
	  .attr("width", x(binsize - 2 * binmargin))
	  .attr("height", function(d) { return height - y(d.numfill); });

    // add the x axis and x-label
    svg.append("g")
	  .attr("class", "x axis")
	  .attr("transform", "translate(0," + height + ")")
	  .call(xAxis);
    svg.append("text")
	  .attr("class", "xlabel")
	  .attr("text-anchor", "middle")
	  .attr("x", width / 2)
	  .attr("y", height + margin.bottom)
	  .text("Number of Edges in Public Graphs (Move on the graph to see detail)");

    // add the y axis and y-label
    svg.append("g")
	  .attr("class", "y axis")
	  .attr("transform", "translate(0,0)")
	  .call(yAxis);
    svg.append("text")
	  .attr("class", "ylabel")
	  .attr("y", 0 - margin.left) // x and y switched due to rotation
	  .attr("x", 0 - (height / 2))
	  .attr("dy", "1em")
	  .attr("transform", "rotate(-90)")
	  .style("text-anchor", "middle")
	  .text("Number of Graphs");
}

// Read in .csv data and make graph
d3.csv("TotalPublicEdges.csv", parser1,
       function(error, csvdata) {
	   mpghist1(csvdata);
});