使用 d3 嵌套组沿多条路径设置 D3 动画标记答案

【问题标题】：D3 animate marker along multiple paths with d3 nest group使用 d3 嵌套组沿多条路径设置 D3 动画标记
【发布时间】：2018-10-24 02:18:55
【问题描述】：

我正在做一个项目，以有多个路径表示地图的路线。我正在关注 this d3 nest example 按一个键对我的数据进行分组以创建多个路由。

我想为圆形元素制作动画，以沿每条单独的路线路径过渡。我可以看到我的问题与this example 和this solution 非常相似，但我不明白如何将解决方案应用于我的示例。

我不明白如何将我的组的索引/键放入 createPathTween 函数。因此，我的第一个组中只有一个圆形元素，而不是沿每条路线/路径过渡的圆形元素。有人可以帮我弄清楚如何在每条路线上放置过渡圆元素吗？

这是我的 d3 代码

<html>
<head>
    <title>Hello</title>
    <script src="http://d3js.org/d3.v4.min.js" charset="utf-8"></script>

    <style>

        }
        .placeVisited{
          fill:#999;
        }

        .journey{
          fill: none;
        }

    </style>
</head>
<body>

<script>

  var width = 1200;
  var height = 550;

  var svg = d3.select( "body" )
      .append( "svg" )
      .attr( "width", width )
      .attr( "height", height );

  var g = svg.append( "g" );

  var projection = d3.geoMercator()
    .center([55, 12])
    .scale(220)
    .translate([width/2,height/2])

  var geoPath = d3.geoPath()
    .projection(projection);

  var voyageLine = d3.line()
    .x(function(d) { return projection([d.lon,d.lat])[0] ; })
    .y(function(d) { return projection([d.lon,d.lat])[1]; })
    .curve(d3.curveBasis);

  var parseDate = d3.timeParse("%d %B %Y");
  var parseYear = d3.timeParse("%Y");


  var color = d3.scaleOrdinal(d3.schemeCategory10);

d3.queue()
  .defer(d3.csv, "multipleVoyages2.csv")
    .await(ready);

function ready (error, data){

  data.forEach(function(d) {
    d.year = parseYear(d.year);
    d.lon= +d.lon;
    d.lat = +d.lat;
  });

var dataNest = d3.nest()
    .key(function(d){return d.VoyageID;})
    .entries(data);

var journey = g.selectAll(".journey")
    .data(dataNest)
    .enter()
    .append("path")
    .attr("class", "journey")
    .style("stroke", function(d) {
      return d.color = color(d.key); })
    .attr("d", function(d){
      return voyageLine(d.values);
    })
    .attr("stroke-dasharray", function() {
        var totalLength = this.getTotalLength();
        return totalLength + " " + totalLength;
            })
    .attr("stroke-dashoffset", function() {
        var totalLength = this.getTotalLength();
        return totalLength;
            })
    .transition()
    .ease(d3.easeLinear)
    .duration(5000)
    .attr("stroke-dashoffset", 0);


var marker = g.append("circle")
      .attr("r", 7)
      .style("fill", "pink")
      .attr("transform", "translate(-100,-100)")
        .transition()
        .ease(d3.easeLinear)
        .duration(5000)
        .attrTween("transform", createPathTween);


var placeGroups = g.selectAll(".placeVisited")
    .data(dataNest)
    .enter()
    .append( "g" )
    .attr("class","placeVisited");

var placeVisited = placeGroups.selectAll("placeVisited")
    .data(function(d){
    return d.values;
  })
    .enter()
    .append("circle")
    .attr("fill", function(d){
      return d.color = color(d.VoyageID);
    })
    .attr("cx", function(d, i) {
      return projection([d.lon, d.lat])[0];

    })
    .attr("cy", function(d, i) {
            return projection([d.lon, d.lat])[1];

    })
    .attr("r", 5)

//transitioning marker

//from this example -- http://fiddle.jshell.net/RnNsE/2/
function createPathTween(d, i, a) {
  // var path = this.parentNode.getElementsByTagName("journey")[0];
   var path = this.parentNode.getElementsByClassName("journey")[i]; //don't understand how to get the index for each group
    var l = path.getTotalLength();
    console.log("path");
    console.log(path);

    return function(t) {
        var p = path.getPointAtLength(t * l);
        return "translate(" + p.x + "," + p.y + ")";
      };

}
}
    </script>
</body>
</html>

还有我的 csv：

VoyageID,VoyageType,voyageName,ObjectID,arrivalDateTxt,year,ObjectNumber,placeName,lon,lat,url,,,
1,Pleasure cruise,Postcards home,170207,14 January 1906,1906,ANMS1113[006],Port Pirie,138.16,-33.183,http://collections.anmm.gov.au/en/objects/details/170207/,,,
1,Pleasure cruise,Postcards home,170205,1 May 1907,1907,ANMS1113[004],Mount Lofty Ranges,138.6,-34.933,http://collections.anmm.gov.au/en/objects/details/170205/,,,
1,Pleasure cruise,Postcards home,170216,26 October 1907,1907,ANMS1113[015],Brisbane,153,-27.5,http://collections.anmm.gov.au/en/objects/details/170216/,,,
1,Pleasure cruise,Postcards home,170200,4 November 1907,1907,ANMS1113[001],Adelaide,138.6,-34.933,http://collections.anmm.gov.au/en/objects/details/170200/,,,
1,Pleasure cruise,Postcards home,170213,26 November 1907,1907,ANMS1113[012],Fremantle,115.766,-32.5,http://collections.anmm.gov.au/en/objects/details/170213/,,,
1,Pleasure cruise,Postcards home,170209,3 December 1907,1907,ANMS1113[008],Adelaide,138.6,-34.933,http://collections.anmm.gov.au/en/objects/details/170209/,,,
1,Pleasure cruise,Postcards home,170212,10 December 1907,1907,ANMS1113[011],Melbourne,144.966,-37.75,http://collections.anmm.gov.au/en/objects/details/170212/,,,
1,Pleasure cruise,Postcards home,170217,20 December 1907,1907,ANMS1113[016],Sydney,151.166,-33.916,http://collections.anmm.gov.au/en/objects/details/170217/,,,
1,Pleasure cruise,Postcards home,170203,26 December 1907,1907,ANMS1113[002],Brisbane,153,-27.5,http://collections.anmm.gov.au/en/objects/details/170203/,,,
1,Pleasure cruise,Postcards home,170215,26 December 1907,1907,ANMS1113[014],Brisbane,153,-27.5,http://collections.anmm.gov.au/en/objects/details/170215/,,,
1,Pleasure cruise,Postcards home,170211,8 January 1908,1908,ANMS1113[010],Port Pirie,138.16,-33.183,http://collections.anmm.gov.au/en/objects/details/170211/,,,
1,Pleasure cruise,Postcards home,170208,14 January 1908,1908,ANMS1113[007],Port Pirie,138.16,-33.183,http://collections.anmm.gov.au/en/objects/details/170208/,,,
2,Kayak adventure,Oskar,1,1 March 1961,1961,,London,-0.127758,51.507351,,,,
2,Kayak adventure,Oskar,2,2 April 1961,1961,,Paris,2.352222,48.856614,,,,
2,Kayak adventure,Oskar,3,3 June 1961,1961,,Lyon,4.835659,45.764043,,,,
2,Kayak adventure,Oskar,4,28 June 1961,1961,,Calais,1.858686,50.95129,,,,
2,Kayak adventure,Oskar,5,10 July 1961,1961,,Frankfurt,8.682127,8.682127,,,,
2,Kayak adventure,Oskar,6,19 December 1961,1961,,Berlin,13.404954,52.520007,,,,
2,Kayak adventure,Oskar,7,25 January 1962,1962,,Amsterdam,4.895168,52.370216,,,,
2,Kayak adventure,Oskar,8,30 June 1962,1962,,rome,12.496366,41.902783,,,,
2,Kayak adventure,Oskar,9,24 November 1962,1962,,Milan,9.189982,45.464204,,,,
2,Kayak adventure,Oskar,10,19 January 1963,1963,,Turin,7.686856,45.070312,,,,
2,Kayak adventure,Oskar,11,27 January 1963,1963,,Florence,11.255814,43.76956,,,,
2,Kayak adventure,Oskar,12,30 April 1963,1963,,Vienna,16.373819,48.208174,,,,
3,Whaling ,Barque Terror,123,12 March 1845,1845,,Island 1,155.370833,-24.916667,,,,
3,Whaling ,Barque Terror,777,15 March 1845,1845,,Island 2,162.81738,-20.6739,,,,
3,Whaling ,Barque Terror,546,22 March 1845,1845,,Place in ocean 3,160.26464,-11.66325,,,,
3,Whaling ,Barque Terror,888,23 July 1845,1845,,Place in ocean 4,161.94638,-10.18388,,,,
3,Whaling ,Barque Terror,543,19 December 1845,1845,,Place in ocean 5,160.90712,-8.94461,,,,
3,Whaling ,Barque Terror,2134,22 January 1846,1846,,Place in ocean 6,158.74232,-9.01835,,,,
3,Whaling ,Barque Terror,6666,30 January 1846,1846,,Back home,157.26555,-8.19361,,,,

【问题讨论】：

所以，您只希望一个圆圈沿着一条路径移动，然后，当该路径结束时，该圆圈开始沿着另一条路径移动，对吗？此外，这里有很多代码/数据。一个更好的想法是使用blockbuilder 创建一个运行示例，这样我们就可以更改函数。
@GerardoFurtado - 非常感谢您的回复和建议，以更好地发布我的代码。我不知道块生成器，但下次我希望在这里寻求帮助时会尝试。

标签： javascript d3.js geojson

【解决方案1】：

你可以让paths在你的path和marker完成使用delay函数后进行动画处理，如下所示：

.duration(5000)
.delay(function(d, i) { // 'i' will give you the index
    return i * 5000; // Multiply by 5000 so that it starts after the previous one has finished.
});

要为每个path 获得一个circle 标记，您需要像这样创建相同数量的circles：

var marker = g.selectAll('circle')
            .data(dataNest).enter()
            .append("circle")...

也可以使用d3.curveCatmullRom 以获得更好的path。

这是plunker

【讨论】：

OP 想要沿路径设置一个或多个圆的动画，而不是为路径本身设置动画。
@GerardoFurtado 哦，我的错……我现在更新了 plunker。谢谢。
太棒了 - 非常感谢您的帮助。这正是我希望达到的@AdityaK。
@user3471259 很高兴我能帮上忙！
太棒了——非常感谢@AdityaK 的帮助。这正是我希望实现的目标——尤其是使用 dataNest 数据为每个单独的路径获取一个圆圈的方法。