使用下拉按钮更新choropleth地图

Updating a choropleth map with a dropdown button

本文关键字：更新 choropleth 地图 按钮      更新时间：2023-09-26

首先，请原谅我英语不好
我正在做一个有网格地图和外部csv的项目。

网格图不是由矩形或六边形组成的，而是仅具有将在末尾使用的任何类型的符号的质心
所以我有一个Topojson文件，其质心为"ID"，质心为"坐标"。

外部CSV由几个列组成，第一列具有相同的质心"ID"，另一列具有不同年份的值。

"ID","C2001","C2002","C2003","C2004","C2005","C2006","C2007","C2008","C2009","C2010","C2000"
6050,"-5.55753","-5.55914","-5.75444","-5.76307","-5.81660","-5.99361","-6.02150","-6.15979","-5.73530","-6.30509","-5.52990"
6051,"-5.55753","-5.55914","-5.75444","-5.76307","-5.81660","-5.99361","-6.02150","-6.15979","-5.73530","-6.30509","-5.52990"

这是我的代码

var width = 960,
    height = 600;
var options = [
    {date: "2000", selected: "+d.C2000"},
    {date: "2001", selected: "+d.C2001"},
    {date: "2002", selected: "+d.C2002"},
    {date: "2003", selected: "+d.C2003"},
    {date: "2004", selected: "+d.C2004"},
    {date: "2005", selected: "+d.C2005"},
    {date: "2006", selected: "+d.C2006"},
    {date: "2007", selected: "+d.C2007"},
    {date: "2008", selected: "+d.C2008"},
    {date: "2009", selected: "+d.C2009"},
    {date: "2010", selected: "+d.C2010"},
];

var color = d3.scale.threshold()
    .domain([-1985, -1400, -1000, -700, -300, -100, -25, -0])
    .range(["#7f0000", "#b30000", "#d7301f", "#ef6548", "#fc8d59", "#fdbb84", "#fdd49e", "#fee8c8", "#fff7ec"]);
var path = d3.geo.path()
    .projection(null)
    .pointRadius(1.5);
var svg = d3.select("body").append("svg")
    .attr("width", width)
    .attr("height", height);

queue()
    .defer(d3.json, "CO2_light.json")
    .defer(d3.csv, "tdd_CO2_emissions.csv")
    .await(ready);
function ready(error, centroid, CO2) {
    var rateById = {};
    console.log(rateById); //To 
    //CO2.forEach(function(d) { rateById[+d.ID] = +d.C2000; });  WORKING FINE = value in rateById
    CO2.forEach(function(d) { rateById[+d.ID] = options[0].selected; }); //NOT WORKING = inside rateById "+d.C2000" instead the value
    svg.selectAll("path")
        .data(topojson.feature(centroid, centroid.objects.CENTROID).features)
      .enter().append("path")
        .attr("class", "centerGrid")
        .attr("d", path)
        .style("fill", function(d) { return color(rateById[+d.properties.ID]); });
    d3.select(".loading").remove();

现在我把按钮留给下一个问题，我专注于下面的这两行

//CO2.forEach(function(d) { rateById[+d.ID] = +d.C2000; });  WORKING FINE = value in rateById
CO2.forEach(function(d) { rateById[+d.ID] = options[0].selected; }); //NOT WORKING = inside rateById "+d.C2000" instead the value

如果我使用第一行，我会得到一个很好的网格图（见图），但如果我试图用第二行从options数组中访问特定年份的值，并执行console.log(rateById);，我会获得这个

Object
6050: "+d.C2000"
6051: "+d.C2000"
6712: "+d.C2000"

而不是这个

Object
6050: -6.30509
6051: -6.30509
6712: -7.0441

此处已修复：http://jsfiddle.net/z7sLdyu2/2/

代码中要做的2个更改：

首先，您选择的选项不应包含要执行的javascript代码（+d.），而应仅包含年份值：

var options = [
  {date: "2000", selected: "C2000"},
  {date: "2001", selected: "C2001"},
  {date: "2002", selected: "C2002"},
  {date: "2003", selected: "C2003"},
  {date: "2004", selected: "C2004"},
  {date: "2005", selected: "C2005"},
  {date: "2006", selected: "C2006"},
  {date: "2007", selected: "C2007"},
  {date: "2008", selected: "C2008"},
  {date: "2009", selected: "C2009"},
  {date: "2010", selected: "C2010"}
];

然后在循环中，通过访问所选年份的数据d属性来分配rateById值，如下所示：

rateById[+d.ID] = +d[options[0].selected];

附言：我不得不在你的jsfiddle中删除你的部分代码，因为在你的版本中找不到质心json，导致了与这个问题无关的错误。

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