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Last active July 23, 2018 22:52
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  1. bsurnida revised this gist Jul 23, 2018. 1 changed file with 1 addition and 1 deletion.
    2 changes: 1 addition & 1 deletion sankey.js
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    d3.sankey = function() {
    var sankey = {},
    nodeWidth = 24,
    nodeWidth = 8,
    nodePadding = 8,
    size = [1, 1],
    nodes = [],
  2. bsurnida revised this gist Jul 23, 2018. No changes.
  3. bsurnida created this gist Jul 23, 2018.
    1 change: 1 addition & 0 deletions .block
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    license: mit
    5 changes: 5 additions & 0 deletions README.md
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    This is a sankey diagram used as an example in the book [D3 Tips and Tricks v4](https://leanpub.com/d3-t-and-t-v4). It is based on a [simpler version here](http://bl.ocks.org/d3noob/013054e8d7807dff76247b81b0e29030).

    It demonstrates the construction of a [sankey diagram](http://bost.ocks.org/mike/sankey/) using d3.js from external csv data that is formatted using just link data and named values.

    forked from <a href='http://bl.ocks.org/d3noob/'>d3noob</a>'s block: <a href='http://bl.ocks.org/d3noob/06e72deea99e7b4859841f305f63ba85'>Sankey diagram using a csv file with v4</a>
    170 changes: 170 additions & 0 deletions index.html
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    <!DOCTYPE html>
    <meta charset="utf-8">
    <title>SANKEY Experiment</title>
    <style>

    .node rect {
    cursor: move;
    fill-opacity: .9;
    shape-rendering: crispEdges;
    }

    .node text {
    pointer-events: none;
    text-shadow: 0 1px 0 #fff;
    }

    .link {
    fill: none;
    stroke: #000;
    stroke-opacity: .2;
    }

    .link:hover {
    stroke-opacity: .5;
    }

    </style>
    <body>

    <script src="https://d3js.org/d3.v4.min.js"></script>
    <script src="sankey.js"></script>
    <script>

    var units = "Widgets";

    // set the dimensions and margins of the graph
    var margin = {top: 10, right: 10, bottom: 10, left: 10},
    width = 700 - margin.left - margin.right,
    height = 300 - margin.top - margin.bottom;

    // format variables
    var formatNumber = d3.format(",.0f"), // zero decimal places
    format = function(d) { return formatNumber(d) + " " + units; },
    color = d3.scaleOrdinal(d3.schemeCategory20);

    // append the svg object to the body of the page
    var svg = d3.select("body").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 + ")");

    // Set the sankey diagram properties
    var sankey = d3.sankey()
    .nodeWidth(36)
    .nodePadding(40)
    .size([width, height]);

    var path = sankey.link();

    // load the data
    d3.csv("sankey.csv", function(error, data) {

    //set up graph in same style as original example but empty
    graph = {"nodes" : [], "links" : []};

    data.forEach(function (d) {
    graph.nodes.push({ "name": d.source });
    graph.nodes.push({ "name": d.target });
    graph.links.push({ "source": d.source,
    "target": d.target,
    "value": +d.value });
    });

    // return only the distinct / unique nodes
    graph.nodes = d3.keys(d3.nest()
    .key(function (d) { return d.name; })
    .object(graph.nodes));

    // loop through each link replacing the text with its index from node
    graph.links.forEach(function (d, i) {
    graph.links[i].source = graph.nodes.indexOf(graph.links[i].source);
    graph.links[i].target = graph.nodes.indexOf(graph.links[i].target);
    });

    // now loop through each nodes to make nodes an array of objects
    // rather than an array of strings
    graph.nodes.forEach(function (d, i) {
    graph.nodes[i] = { "name": d };
    });

    sankey
    .nodes(graph.nodes)
    .links(graph.links)
    .layout(32);

    // add in the links
    var link = svg.append("g").selectAll(".link")
    .data(graph.links)
    .enter().append("path")
    .attr("class", "link")
    .attr("d", path)
    .style("stroke-width", function(d) { return Math.max(1, d.dy); })
    .sort(function(a, b) { return b.dy - a.dy; });

    // add the link titles
    link.append("title")
    .text(function(d) {
    return d.source.name + " → " +
    d.target.name + "\n" + format(d.value); });

    // add in the nodes
    var node = svg.append("g").selectAll(".node")
    .data(graph.nodes)
    .enter().append("g")
    .attr("class", "node")
    .attr("transform", function(d) {
    return "translate(" + d.x + "," + d.y + ")"; })
    .call(d3.drag()
    .subject(function(d) {
    return d;
    })
    .on("start", function() {
    this.parentNode.appendChild(this);
    })
    .on("drag", dragmove));

    // add the rectangles for the nodes
    node.append("rect")
    .attr("height", function(d) { return d.dy; })
    .attr("width", sankey.nodeWidth())
    .style("fill", function(d) {
    return d.color = color(d.name.replace(/ .*/, "")); })
    .style("stroke", function(d) {
    return d3.rgb(d.color).darker(2); })
    .append("title")
    .text(function(d) {
    return d.name + "\n" + format(d.value); });

    // add in the title for the nodes
    node.append("text")
    .attr("x", -6)
    .attr("y", function(d) { return d.dy / 2; })
    .attr("dy", ".35em")
    .attr("text-anchor", "end")
    .attr("transform", null)
    .text(function(d) { return d.name; })
    .filter(function(d) { return d.x < width / 2; })
    .attr("x", 6 + sankey.nodeWidth())
    .attr("text-anchor", "start");

    // the function for moving the nodes
    function dragmove(d) {
    d3.select(this)
    .attr("transform",
    "translate("
    + d.x + ","
    + (d.y = Math.max(
    0, Math.min(height - d.dy, d3.event.y))
    ) + ")");
    sankey.relayout();
    link.attr("d", path);
    }
    });

    </script>

    </body>

    8 changes: 8 additions & 0 deletions sankey.csv
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    source,target,value
    Barry,Elvis,2
    Frodo,Elvis,2
    Frodo,Sarah,2
    Barry,Alice,2
    Elvis,Sarah,2
    Elvis,Alice,2
    Sarah,Alice,4
    294 changes: 294 additions & 0 deletions sankey.js
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    d3.sankey = function() {
    var sankey = {},
    nodeWidth = 24,
    nodePadding = 8,
    size = [1, 1],
    nodes = [],
    links = [];

    sankey.nodeWidth = function(_) {
    if (!arguments.length) return nodeWidth;
    nodeWidth = +_;
    return sankey;
    };

    sankey.nodePadding = function(_) {
    if (!arguments.length) return nodePadding;
    nodePadding = +_;
    return sankey;
    };

    sankey.nodes = function(_) {
    if (!arguments.length) return nodes;
    nodes = _;
    return sankey;
    };

    sankey.links = function(_) {
    if (!arguments.length) return links;
    links = _;
    return sankey;
    };

    sankey.size = function(_) {
    if (!arguments.length) return size;
    size = _;
    return sankey;
    };

    sankey.layout = function(iterations) {
    computeNodeLinks();
    computeNodeValues();
    computeNodeBreadths();
    computeNodeDepths(iterations);
    computeLinkDepths();
    return sankey;
    };

    sankey.relayout = function() {
    computeLinkDepths();
    return sankey;
    };

    sankey.link = function() {
    var curvature = .5;

    function link(d) {
    var x0 = d.source.x + d.source.dx,
    x1 = d.target.x,
    xi = d3.interpolateNumber(x0, x1),
    x2 = xi(curvature),
    x3 = xi(1 - curvature),
    y0 = d.source.y + d.sy + d.dy / 2,
    y1 = d.target.y + d.ty + d.dy / 2;
    return "M" + x0 + "," + y0
    + "C" + x2 + "," + y0
    + " " + x3 + "," + y1
    + " " + x1 + "," + y1;
    }

    link.curvature = function(_) {
    if (!arguments.length) return curvature;
    curvature = +_;
    return link;
    };

    return link;
    };

    // Populate the sourceLinks and targetLinks for each node.
    // Also, if the source and target are not objects, assume they are indices.
    function computeNodeLinks() {
    nodes.forEach(function(node) {
    node.sourceLinks = [];
    node.targetLinks = [];
    });
    links.forEach(function(link) {
    var source = link.source,
    target = link.target;
    if (typeof source === "number") source = link.source = nodes[link.source];
    if (typeof target === "number") target = link.target = nodes[link.target];
    source.sourceLinks.push(link);
    target.targetLinks.push(link);
    });
    }

    // Compute the value (size) of each node by summing the associated links.
    function computeNodeValues() {
    nodes.forEach(function(node) {
    node.value = Math.max(
    d3.sum(node.sourceLinks, value),
    d3.sum(node.targetLinks, value)
    );
    });
    }

    // Iteratively assign the breadth (x-position) for each node.
    // Nodes are assigned the maximum breadth of incoming neighbors plus one;
    // nodes with no incoming links are assigned breadth zero, while
    // nodes with no outgoing links are assigned the maximum breadth.
    function computeNodeBreadths() {
    var remainingNodes = nodes,
    nextNodes,
    x = 0;

    while (remainingNodes.length) {
    nextNodes = [];
    remainingNodes.forEach(function(node) {
    node.x = x;
    node.dx = nodeWidth;
    node.sourceLinks.forEach(function(link) {
    if (nextNodes.indexOf(link.target) < 0) {
    nextNodes.push(link.target);
    }
    });
    });
    remainingNodes = nextNodes;
    ++x;
    }

    //
    moveSinksRight(x);
    scaleNodeBreadths((size[0] - nodeWidth) / (x - 1));
    }

    function moveSourcesRight() {
    nodes.forEach(function(node) {
    if (!node.targetLinks.length) {
    node.x = d3.min(node.sourceLinks, function(d) { return d.target.x; }) - 1;
    }
    });
    }

    function moveSinksRight(x) {
    nodes.forEach(function(node) {
    if (!node.sourceLinks.length) {
    node.x = x - 1;
    }
    });
    }

    function scaleNodeBreadths(kx) {
    nodes.forEach(function(node) {
    node.x *= kx;
    });
    }

    function computeNodeDepths(iterations) {
    var nodesByBreadth = d3.nest()
    .key(function(d) { return d.x; })
    .sortKeys(d3.ascending)
    .entries(nodes)
    .map(function(d) { return d.values; });

    //
    initializeNodeDepth();
    resolveCollisions();
    for (var alpha = 1; iterations > 0; --iterations) {
    relaxRightToLeft(alpha *= .99);
    resolveCollisions();
    relaxLeftToRight(alpha);
    resolveCollisions();
    }

    function initializeNodeDepth() {
    var ky = d3.min(nodesByBreadth, function(nodes) {
    return (size[1] - (nodes.length - 1) * nodePadding) / d3.sum(nodes, value);
    });

    nodesByBreadth.forEach(function(nodes) {
    nodes.forEach(function(node, i) {
    node.y = i;
    node.dy = node.value * ky;
    });
    });

    links.forEach(function(link) {
    link.dy = link.value * ky;
    });
    }

    function relaxLeftToRight(alpha) {
    nodesByBreadth.forEach(function(nodes, breadth) {
    nodes.forEach(function(node) {
    if (node.targetLinks.length) {
    var y = d3.sum(node.targetLinks, weightedSource) / d3.sum(node.targetLinks, value);
    node.y += (y - center(node)) * alpha;
    }
    });
    });

    function weightedSource(link) {
    return center(link.source) * link.value;
    }
    }

    function relaxRightToLeft(alpha) {
    nodesByBreadth.slice().reverse().forEach(function(nodes) {
    nodes.forEach(function(node) {
    if (node.sourceLinks.length) {
    var y = d3.sum(node.sourceLinks, weightedTarget) / d3.sum(node.sourceLinks, value);
    node.y += (y - center(node)) * alpha;
    }
    });
    });

    function weightedTarget(link) {
    return center(link.target) * link.value;
    }
    }

    function resolveCollisions() {
    nodesByBreadth.forEach(function(nodes) {
    var node,
    dy,
    y0 = 0,
    n = nodes.length,
    i;

    // Push any overlapping nodes down.
    nodes.sort(ascendingDepth);
    for (i = 0; i < n; ++i) {
    node = nodes[i];
    dy = y0 - node.y;
    if (dy > 0) node.y += dy;
    y0 = node.y + node.dy + nodePadding;
    }

    // If the bottommost node goes outside the bounds, push it back up.
    dy = y0 - nodePadding - size[1];
    if (dy > 0) {
    y0 = node.y -= dy;

    // Push any overlapping nodes back up.
    for (i = n - 2; i >= 0; --i) {
    node = nodes[i];
    dy = node.y + node.dy + nodePadding - y0;
    if (dy > 0) node.y -= dy;
    y0 = node.y;
    }
    }
    });
    }

    function ascendingDepth(a, b) {
    return a.y - b.y;
    }
    }

    function computeLinkDepths() {
    nodes.forEach(function(node) {
    node.sourceLinks.sort(ascendingTargetDepth);
    node.targetLinks.sort(ascendingSourceDepth);
    });
    nodes.forEach(function(node) {
    var sy = 0, ty = 0;
    node.sourceLinks.forEach(function(link) {
    link.sy = sy;
    sy += link.dy;
    });
    node.targetLinks.forEach(function(link) {
    link.ty = ty;
    ty += link.dy;
    });
    });

    function ascendingSourceDepth(a, b) {
    return a.source.y - b.source.y;
    }

    function ascendingTargetDepth(a, b) {
    return a.target.y - b.target.y;
    }
    }

    function center(node) {
    return node.y + node.dy / 2;
    }

    function value(link) {
    return link.value;
    }

    return sankey;
    };