Recently, I have started learning about javascript and D3.js, and I am eager to grasp their functionalities. My current focus is on experimenting with the force-directed graph example available at: http://bl.ocks.org/mbostock/4062045
My goal is to modify the JSON data by replacing the array numbers with actual node names. This adjustment is crucial for visualizing a small network topology where I have already set up the node neighbors. Here is the JSON data I intend to use:
{
"nodes":[
{"name":"stkbl0001","group":1},
{"name":"stkbl0002","group":1},
{"name":"stkbl0003","group":1},
{"name":"stkbl0004","group":1},
{"name":"stkbl0005","group":1}
],
"links":[
{"source":"stkbl0001","target":"stkbl0005","value":3},
{"source":"stkbl0002","target":"stkbl0005","value":3},
{"source":"stkbl0003","target":"stkbl0005","value":3},
{"source":"stkbl0004","target":"stkbl0005","value":3}
]
Despite my efforts, I am unable to figure out how to modify the D3 code to incorporate these changes seamlessly. The part where the array numbers are retrieved and connected as links remains obscure to me. While I acknowledge that this may seem like a trivial query, any assistance in this matter would be greatly appreciated!
EDIT:
Below is the current state of the javascript code, following the suggestions provided by Lars Kotthoff:
<!DOCTYPE html>
<meta charset="utf-8">
<style>
.node {
stroke: #fff;
stroke-width: 1.5px;
}
.link {
stroke: #999;
stroke-opacity: .6;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script>
var width = 960,
height = 500;
var color = d3.scale.category20();
var force = d3.layout.force()
.charge(-120)
.linkDistance(30)
.size([width, height]);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
d3.json("mini.json", function(error, graph) {
force
.nodes(graph.nodes)
.links(graph.links)
.start();
var link = svg.selectAll(".link")
.data(graph.links)
.enter().append("line")
.attr("class", "link")
.style("stroke-width", function(d) { return Math.sqrt(d.value); });
var node = svg.selectAll(".node")
.data(graph.nodes)
.enter().append("circle")
.attr("class", "node")
.attr("r", 5)
.style("fill", function(d) { return color(d.group); })
.call(force.drag);
var nodeMap = {};
graph.nodes.forEach(function(d) { nodeMap[d.name] = d; });
graph.links.forEach(function(l) {
l.source = nodeMap[l.source];
l.target = nodeMap[l.target];
})
node.append("title")
.text(function(d) { return d.name; });
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>
On line 55, the code encounters an error (nodes.forEach(function(d) { nodeMap[d.name] = d; });) with the following message:
Uncaught ReferenceError: nodes is not defined