D3NodeUpdateData

The underlying data can be updated

by Simon Raper

HTML

<script src="http://labratrevenge.com/d3-tip/javascripts/d3.tip.v0.6.3.js"></script>
<script type="application/json" id="misUpdated">
    {
        "links": [{
            "source": {
                "name": "Myriel",
                    "group": 1
            },
                "target": {
                "name": "Napoleon",
                    "group": 1
            },
                "value": 1
        }, {
            "source": {
                "name": "Napoleon",
                    "group": 1
            },
                "target": {
                "name": "Mlle.Baptistine",
                    "group": 1
            },
                "value": 1
        }, {
            "source": {
                "name": "Mme.Magloire",
                    "group": 1
            },
                "target": {
                "name": "CountessdeLo",
                    "group": 1
            },
                "value": 1
        }]
    }
</script>
<script type="application/json" id="misAddBackIn">
    {
        "links": [{
            "source": {
                "name": "Myriel",
                    "group": 1
            },
                "target": {
                "name": "Napoleon",
                    "group": 1
            },
                "value": 1
        }, {
            "source": {
                "name": "Napoleon",
                    "group": 1
            },
                "target": {
                "name": "Mlle.Baptistine",
                    "group": 1
            },
                "value": 1
        }, {
            "source": {
                "name": "Mme.Magloire",
                    "group": 1
            },
                "target": {
                "name": "CountessdeLo",
                    "group": 1
            },
                "value": 1
        }, {
            "source": {
                "name": "Mme.Magloire",
                    "group": 1
            },
                "target": {
                "name": "Fantine",
           ...

CSS

.node {
    stroke: #fff;
    stroke-width: 1.5px;
}
.link {
    stroke: #999;
    stroke-opacity: .6;
}

JavaScript

//Constants for the SVG
var width = 500,
    height = 500;

//Set up the colour scale
var color = d3.scale.category20();

//Set up the force layout
var force = d3.layout.force()
    .charge(-120)
    .linkDistance(30)
    .size([width, height]);

//Append a SVG to the body of the html page. Assign this SVG as an object to svg
var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

//Read the data from the mis element 
var mis = document.getElementById('mis').innerHTML;
graph = JSON.parse(mis);

//Creates the graph data structure out of the json data
force.nodes(graph.nodes)
    .links(graph.links)
    .start();

//Create all the line svgs but without locations yet
var link = svg.selectAll(".link")
    .data(graph.links)
    .enter().append("line")
    .attr("class", "link")
    .style("stroke-width", function (d) {
    return Math.sqrt(d.value);
});

//Do the same with the circles for the nodes - no 
var node = svg.selectAll(".node")
    .data(graph.nodes)
    .enter().append("circle")
    .attr("class", "node")
    .attr("r", 8)
    .style("fill", function (d) {
    return color(d.group);
})
    .call(force.drag);


//Now we are giving the SVGs co-ordinates - the force layout is generating the co-ordinates which this code is using to update the attributes of the SVG elements
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) {
        //console.log(d.name)
        return d.x;
    })
        .attr("cy", function (d) {
        return d.y;
    });

});




setTimeout(function () {
    changeGraph('misUpdated')
}, 1000);

setTimeout(function () {
    changeGraph('misAddBackIn')
}, 2000);

function changeGraph(jsonSource) {

    //Read...