I would like to place pie charts on the node of a D3 force directed layout graph using D3.js. This is a common visualization in population genetics, see for example http://mathildasanthropologyblog.files.wordpress.com/2008/06/as3.jpg
I've started with a very basic graph plot:
<!DOCTYPE html>
<html lang="en">
<head>
<script type="text/javascript" src="d3/d3.v3.js"></script>
</head>
<body>
<script type="text/javascript">
graph = { "nodes":[{"proportions": [{"group": 1, "value": 1},
{"group": 2, "value": 2},
{"group": 3, "value": 3}]},
{"proportions": [{"group": 1, "value": 2},
{"group": 2, "value": 2},
{"group": 3, "value": 2}]}],
"links":[{"source": 0, "target": 1, "length": 500, "width": 1}]
}
var width = 960,
height = 500,
radius = 10,
color = d3.scale.category20c();
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var force = d3.layout.force()
.charge(-120)
.size([width, height]);
force
.nodes(graph.nodes)
.links(graph.links)
.start();
var link = svg.selectAll(".link")
.data(graph.links)
.enter().append("line")
.attr("class", "link");
var node = svg.selectAll(".node")
.data(graph.nodes)
.enter().append("circle")
.attr("class", "node")
.attr("r", radius)
.call(force.drag);
force.on("tick", function() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("cx", function(d) { return d.x; })
.attr("cy", function(d) { return d.y; });
});
</script>
</body>
</html>
But when I try to replace the circle nodes with pie charts, the pie charts all end up stacked in the corner of the plot.
<!DOCTYPE html>
<html lang="en">
<head>
<script type="text/javascript" src="d3/d3.v3.js"></script>
</head>
<body>
<script type="text/javascript">
graph = { "nodes":[{"proportions": [{"group": 1, "value": 1},
{"group": 2, "value": 2},
{"group": 3, "value": 3}]},
{"proportions": [{"group": 1, "value": 2},
{"group": 2, "value": 2},
{"group": 3, "value": 2}]}],
"links":[{"source": 0, "target": 1, "length": 500, "width": 1}]
}
var width = 960,
height = 500,
radius = 10,
color = d3.scale.category20c();
var pie = d3.layout.pie()
.sort(null)
.value(function(d) { return d.value; });
var arc = d3.svg.arc()
.outerRadius(radius)
.innerRadius(0);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var force = d3.layout.force()
.charge(-120)
.size([width, height]);
force
.nodes(graph.nodes)
.links(graph.links)
.start();
var link = svg.selectAll(".link")
.data(graph.links)
.enter().append("line")
.attr("class", "link");
var node = svg.selectAll(".node")
.data(graph.nodes)
.enter().append("g")
.attr("class", "node");
node.selectAll("path")
.data(function(d) {return pie(d.proportions); })
.enter().append("svg:path")
.attr("d", arc)
.style("fill", function(d) { return color(d.group); });;
force.on("tick", function() {
link.attr("x1", function(d) { return d.source.x; })
.attr("y1", function(d) { return d.source.y; })
.attr("x2", function(d) { return d.target.x; })
.attr("y2", function(d) { return d.target.y; });
node.attr("x", function(d) { return d.x; })
.attr("y", function(d) { return d.y; });
});
</script>
</body>
</html>
Any assistance would be very appreciated!
The code as above wasn't working, the snippet below displays both pie charts, in the right location, with edges visible and with pie chart colors:
The problem appears to be the last statement in your force-on-tick callback:
SVG paths have no such x/y attributes. Try translating the path instead: