json - Sankey图过渡

Question

我想知道是否有一种简单的方法来修改Sankey diagram example，以便顺利过渡到新数据。例如，假设我有不同的数据文件(energy1.json，energy2.json ...)，则d3如何为第一个数据集绘制Sankey图，然后等待，然后重新排列框的位置以表示第二个数据集？

Answer 1

这个有可能。这是使用csv文件的一种方法。在这里工作的Sankey:https://www.betterment.com/resources/investment-strategy/portfolio-management/portfolio-diversification/

在d3.csv调用之外定义一个全局数组。

var portfolioValues = [];

解析csv以创建节点/链接结构时，将值推送到全局数组。

d3.csv("etf-geo.csv", function(error, data) {
    graph = {"nodes" : [], "links" : []};
    data.forEach(function (d, i) {
        var item = { source: d.source, target: d.target, values: [] };
        for (var j=0; j < 101; j++) {
            item.values.push(d['value'+j.toString()]);
        }
        portfolioValues.push(item);
        graph.nodes.push({ "name": d.source });
        graph.nodes.push({ "name": d.target });
        graph.links.push({
            source: portfolioValues[i].source,
            target: portfolioValues[i].target,
            value: portfolioValues[i].values[startingAllocation]
        });
    });

//this handy little function returns only the distinct / unique nodes
graph.nodes = d3.keys(
    d3.nest()
        .key(function (d) { return d.name; })
        .map(graph.nodes)
);

// it appears d3 with force layout wants a numeric source and target
// so 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);
    portfolioValues[i].source = graph.links[i].source;
    portfolioValues[i].target = 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 };
});

// construct sankey
sankey
    .nodes(graph.nodes)
    .links(graph.links)
    .layout();

监听更改并将用户输入传递给您的更新功能。

$(".sankey-slider").bind("slider:changed", function (event, data) {

slideValue = data.value;

updateData(parseInt(slideValue));

 });

创建一个临时数组，然后从全局数组中检索正确的值。调用sankey函数以重新计算布局。

    var newLinks = [];

    portfolioValues.forEach(function(p, i) {
        newLinks.push({
          source: p.source,
          target: p.target,
          value: p.values[allocation]
        });
    });

    graph.links = newLinks;

    sankey
    .nodes(graph.nodes)
    .links(graph.links)
    .size([width, height])
    .layout();

选择每个需要更改的元素并传递新的数据值。

d3.selectAll(".link")
  .data(graph.links)
  .attr("d", path)
  .attr("id", function(d,i){
    d.id = i;
    return "link-"+i;
  })
  .style("stroke-width", function(d) { return Math.max(1, d.dy); })
  .sort(function(a, b) { return b.dy - a.dy; });

d3.selectAll(".node").attr("transform", function(d) {
  return "translate(" + d.x + "," + d.y + ")"; });

d3.selectAll("rect")
.attr("height", function(d) { return d.dy; })
.on("mouseover",highlight_node_links)
.on("mouseout",onNodeMouseout);

在这里工作sankey:
https://www.betterment.com/resources/investment-strategy/portfolio-management/portfolio-diversification/