Skip to content

Instantly share code, notes, and snippets.

@d3noob
Last active November 30, 2019 18:24
  • Star 0 You must be signed in to star a gist
  • Fork 1 You must be signed in to fork a gist
Star You must be signed in to star a gist
Save d3noob/5015397 to your computer and use it in GitHub Desktop.
Sankey diagram of greenhouse gas production in 2005
license: mit

This is an example of a Sankey diagram made using d3.js and the sankey plugin.

A description of how it was put together and techniques for implimenting Sankey diagrams in general with d3.js can be found at d3noob.org or you can download the full text in the D3 Tips and Tricks book (for free) from Leanpub.

The data is sourced from the World Resources Institute (http://www.wri.org/chart/world-greenhouse-gas-emissions-2005). Open in full window for full effect.

<!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>
<p id="chart">
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.17/d3.min.js"></script>
<script src="sankey.js"></script>
<script>
var units = "Widgets";
var margin = {top: 10, right: 10, bottom: 10, left: 10},
width = 1200 - margin.left - margin.right,
height = 740 - margin.top - margin.bottom;
var formatNumber = d3.format(",.0f"), // zero decimal places
format = function(d) { return formatNumber(d) + " " + units; },
color = d3.scale.category20();
// append the svg canvas to the page
var svg = d3.select("#chart").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(10)
.size([width, height]);
var path = sankey.link();
// load the data
d3.json("sankeygreenhouse.json", function(error, graph) {
var nodeMap = {};
graph.nodes.forEach(function(x) { nodeMap[x.name] = x; });
graph.links = graph.links.map(function(x) {
return {
source: nodeMap[x.source],
target: nodeMap[x.target],
value: x.value
};
});
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.behavior.drag()
.origin(function(d) { return d; })
.on("dragstart", 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>
</html>
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) {
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;
};
{
"links": [
{"source":"Agricultural Energy Use","target":"Carbon Dioxide","value":"1.4"},
{"source":"Agriculture","target":"Agriculture Soils","value":"5.2"},
{"source":"Agriculture","target":"Livestock and Manure","value":"5.4"},
{"source":"Agriculture","target":"Other Agriculture","value":"1.7"},
{"source":"Agriculture","target":"Rice Cultivation","value":"1.5"},
{"source":"Agriculture Soils","target":"Nitrous Oxide","value":"5.2"},
{"source":"Air","target":"Carbon Dioxide","value":"1.7"},
{"source":"Aluminium Non-Ferrous Metals","target":"Carbon Dioxide","value":"1.0"},
{"source":"Aluminium Non-Ferrous Metals","target":"HFCs - PFCs","value":"0.2"},
{"source":"Cement","target":"Carbon Dioxide","value":"5.0"},
{"source":"Chemicals","target":"Carbon Dioxide","value":"3.4"},
{"source":"Chemicals","target":"HFCs - PFCs","value":"0.5"},
{"source":"Chemicals","target":"Nitrous Oxide","value":"0.2"},
{"source":"Coal Mining","target":"Carbon Dioxide","value":"0.1"},
{"source":"Coal Mining","target":"Methane","value":"1.2"},
{"source":"Commercial Buildings","target":"Carbon Dioxide","value":"6.3"},
{"source":"Deforestation","target":"Carbon Dioxide","value":"10.9"},
{"source":"Electricity and heat","target":"Agricultural Energy Use","value":"0.4"},
{"source":"Electricity and heat","target":"Aluminium Non-Ferrous Metals","value":"0.4"},
{"source":"Electricity and heat","target":"Cement","value":"0.3"},
{"source":"Electricity and heat","target":"Chemicals","value":"1.3"},
{"source":"Electricity and heat","target":"Commercial Buildings","value":"5.0"},
{"source":"Electricity and heat","target":"Food and Tobacco","value":"0.5"},
{"source":"Electricity and heat","target":"Iron and Steel","value":"1.0"},
{"source":"Electricity and heat","target":"Machinery","value":"1.0"},
{"source":"Electricity and heat","target":"Oil and Gas Processing","value":"0.4"},
{"source":"Electricity and heat","target":"Other Industry","value":"2.7"},
{"source":"Electricity and heat","target":"Pulp - Paper and Printing","value":"0.6"},
{"source":"Electricity and heat","target":"Residential Buildings","value":"5.2"},
{"source":"Electricity and heat","target":"T and D Losses","value":"2.2"},
{"source":"Electricity and heat","target":"Unallocated Fuel Combustion","value":"2.0"},
{"source":"Energy","target":"Electricity and heat","value":"24.9"},
{"source":"Energy","target":"Fugitive Emissions","value":"4.0"},
{"source":"Energy","target":"Industry","value":"14.7"},
{"source":"Energy","target":"Other Fuel Combustion","value":"8.6"},
{"source":"Energy","target":"Transportation","value":"14.3"},
{"source":"Food and Tobacco","target":"Carbon Dioxide","value":"1.0"},
{"source":"Fugitive Emissions","target":"Coal Mining","value":"1.3"},
{"source":"Fugitive Emissions","target":"Oil and Gas Processing","value":"3.2"},
{"source":"Harvest \/ Management","target":"Carbon Dioxide","value":"1.3"},
{"source":"Industrial Processes","target":"Aluminium Non-Ferrous Metals","value":"0.4"},
{"source":"Industrial Processes","target":"Cement","value":"2.8"},
{"source":"Industrial Processes","target":"Chemicals","value":"1.4"},
{"source":"Industrial Processes","target":"Other Industry","value":"0.5"},
{"source":"Industry","target":"Aluminium Non-Ferrous Metals","value":"0.4"},
{"source":"Industry","target":"Cement","value":"1.9"},
{"source":"Industry","target":"Chemicals","value":"1.4"},
{"source":"Industry","target":"Food and Tobacco","value":"0.5"},
{"source":"Industry","target":"Iron and Steel","value":"3.0"},
{"source":"Industry","target":"Oil and Gas Processing","value":"2.8"},
{"source":"Industry","target":"Other Industry","value":"3.8"},
{"source":"Industry","target":"Pulp - Paper and Printing","value":"0.5"},
{"source":"Iron and Steel","target":"Carbon Dioxide","value":"4.0"},
{"source":"Land Use Change","target":"Deforestation","value":"10.9"},
{"source":"Land Use Change","target":"Harvest \/ Management","value":"1.3"},
{"source":"Landfills","target":"Methane","value":"1.7"},
{"source":"Livestock and Manure","target":"Methane","value":"5.1"},
{"source":"Livestock and Manure","target":"Nitrous Oxide","value":"0.3"},
{"source":"Machinery","target":"Carbon Dioxide","value":"1.0"},
{"source":"Oil and Gas Processing","target":"Carbon Dioxide","value":"3.6"},
{"source":"Oil and Gas Processing","target":"Methane","value":"2.8"},
{"source":"Other Agriculture","target":"Methane","value":"1.4"},
{"source":"Other Agriculture","target":"Nitrous Oxide","value":"0.3"},
{"source":"Other Fuel Combustion","target":"Agricultural Energy Use","value":"1.0"},
{"source":"Other Fuel Combustion","target":"Commercial Buildings","value":"1.3"},
{"source":"Other Fuel Combustion","target":"Residential Buildings","value":"5.0"},
{"source":"Other Fuel Combustion","target":"Unallocated Fuel Combustion","value":"1.8"},
{"source":"Other Industry","target":"Carbon Dioxide","value":"6.6"},
{"source":"Other Industry","target":"HFCs - PFCs","value":"0.4"},
{"source":"Pulp - Paper and Printing","target":"Carbon Dioxide","value":"1.1"},
{"source":"Rail - Ship and Other Transport","target":"Carbon Dioxide","value":"2.5"},
{"source":"Residential Buildings","target":"Carbon Dioxide","value":"10.2"},
{"source":"Rice Cultivation","target":"Methane","value":"1.5"},
{"source":"Road","target":"Carbon Dioxide","value":"10.5"},
{"source":"T and D Losses","target":"Carbon Dioxide","value":"2.2"},
{"source":"Transportation","target":"Air","value":"1.7"},
{"source":"Transportation","target":"Rail - Ship and Other Transport","value":"2.5"},
{"source":"Transportation","target":"Road","value":"10.5"},
{"source":"Unallocated Fuel Combustion","target":"Carbon Dioxide","value":"3.0"},
{"source":"Unallocated Fuel Combustion","target":"Methane","value":"0.4"},
{"source":"Unallocated Fuel Combustion","target":"Nitrous Oxide","value":"0.4"},
{"source":"Waste","target":"Landfills","value":"1.7"},
{"source":"Waste","target":"Waste water - Other Waste","value":"1.5"},
{"source":"Waste water - Other Waste","target":"Methane","value":"1.2"},
{"source":"Waste water - Other Waste","target":"Nitrous Oxide","value":"0.3"}
] ,
"nodes": [
{"name":"Energy"},
{"name":"Industrial Processes"},
{"name":"Electricity and heat"},
{"name":"Industry"},
{"name":"Land Use Change"},
{"name":"Agriculture"},
{"name":"Waste"},
{"name":"Transportation"},
{"name":"Other Fuel Combustion"},
{"name":"Fugitive Emissions"},
{"name":"Road"},{"name":"Air"},
{"name":"Rail - Ship and Other Transport"},
{"name":"Residential Buildings"},
{"name":"Commercial Buildings"},
{"name":"Unallocated Fuel Combustion"},
{"name":"Iron and Steel"},
{"name":"Aluminium Non-Ferrous Metals"},
{"name":"Machinery"},
{"name":"Pulp - Paper and Printing"},
{"name":"Food and Tobacco"},
{"name":"Chemicals"},
{"name":"Cement"},
{"name":"Other Industry"},
{"name":"T and D Losses"},
{"name":"Coal Mining"},
{"name":"Oil and Gas Processing"},
{"name":"Deforestation"},
{"name":"Harvest \/ Management"},
{"name":"Agricultural Energy Use"},
{"name":"Agriculture Soils"},
{"name":"Livestock and Manure"},
{"name":"Rice Cultivation"},
{"name":"Other Agriculture"},
{"name":"Landfills"},
{"name":"Waste water - Other Waste"},
{"name":"Carbon Dioxide"},
{"name":"HFCs - PFCs"},
{"name":"Methane"},
{"name":"Nitrous Oxide"}
] }
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment