Question

我在地图中进行缩放时出现问题，因为标签显示重复。我知道我的问题出现了，因为在我的缩放中我不删除标签。我知道问题出在哪里，我需要在进行缩放时删除最旧的标签，但我不知道如何以及在何处解决此问题。

有什么想法吗？适合所有人。

<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  margin: 0;
}

path {
  fill: none;
  stroke: green;
  stroke-linejoin: round;
  stroke-width: 1.5px;
}

</style>
<body>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/topojson/1.6.19/topojson.min.js"></script>
<script src="d3.geo.tile.min.js"></script>
<script>

var width = Math.max(960, window.innerWidth),
    height = Math.max(600, window.innerHeight);

var tile = d3.geo.tile()
    .size([width, height]);

var projection = d3.geo.mercator()
    .scale((3 << 12) / 2 / Math.PI)
    .translate([width / 2, height / 2]);

var center = projection([-3, 36]);

var path = d3.geo.path()
    .projection(projection);

var zoom = d3.behavior.zoom()
    .scale(projection.scale() * 2 * Math.PI)
    .translate([width - center[0], height - center[1]])
    .on("zoom", zoomed);

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

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

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

var vector = svg.append("path");

d3.json("es.json", function(error, es) {
  if (error) throw error;
  svg.call(zoom);
  vector.datum(topojson.mesh(es, es.objects.provinces));

  zoomed();
});



function zoomed() {


d3.csv("data/country-capitals.csv", function(err, capitals) {
    capitals.forEach(function(i){
      addpoint(i.CapitalLongitude, i.CapitalLatitude, i.CapitalName );
    });
  });

  var tiles = tile
      .scale(zoom.scale())
      .translate(zoom.translate())
      ();

  projection
      .scale(zoom.scale() / 2 / Math.PI)
      .translate(zoom.translate());

  vector
      .attr("d", path);

  var image = raster
      .attr("transform", "scale(" + tiles.scale + ")translate(" + tiles.translate + ")")
    .selectAll("image")
      .data(tiles, function(d) { return d; });

  image.exit()
      .remove();



  image.enter().append("image")
      .attr("xlink:href", function(d) { return "http://" + ["a", "b", "c"][Math.random() * 3 | 0] + ".tile.openstreetmap.org/" + d[2] + "/" + d[0] + "/" + d[1] + ".png"; })
      .attr("width", 1)
      .attr("height", 1)
      .attr("x", function(d) { return d[0]; })
      .attr("y", function(d) { return d[1]; });
}

   function addpoint(lat,lon,text) {

  var gpoint = g.append("g").attr("class", "gpoint");
  var x = projection([lat,lon])[0];
  var y = projection([lat,lon])[1];

  gpoint.append("svg:circle")
        .attr("cx", x)
        .attr("cy", y)
        .attr("class","point")
        .attr("r", 1.5);

  //conditional in case a point has no associated text
     if(text.length>0){

    gpoint.append("text")
          .attr("x", x+2)
          .attr("y", y+2)
          .attr("class","text")
          .text(text);
  }

}


   </script>

CSV在这里：

CountryName,CapitalName,CapitalLatitude,CapitalLongitude,CountryCode,ContinentName
Brazil,Brasilia,-15.783333333333333,-47.916667,BR,South America
Colombia,Bogota,4.6,-74.083333,CO,South America
Egypt,Cairo,30.05,31.250000,EG,Africa
France,Paris,48.86666666666667,2.333333,FR,Europe
Iraq,Baghdad,33.333333333333336,44.400000,IQ,Asia
South Korea,Seoul,37.55,126.983333,KR,Asia
Kosovo,Pristina,42.666666666666664,21.166667,KO,Europe
Mexico,Mexico City,19.433333333333334,-99.133333,MX,Central America

Answer 1

在缩放之前，您可以删除所有包含文本和组的组，如下所示：

function zoomed() {

  d3.selectAll(".gpoint").remove();

  d3.csv("my.csv", function(err, capitals) {
    capitals.forEach(function(i){
      addpoint(i.CapitalLongitude, i.CapitalLatitude, i.CapitalName );
    });
  });
 //your code

工作代码here

如何解决缩放中的重复标签问题

1 个答案: