时间戳

首页 > 解决方案 > 使用 d3.geoPath(projection) 似乎没有将正确的属性“d”添加到“路径”中

javascript - 使用 d3.geoPath(projection) 似乎没有将正确的属性“d”添加到“路径”中

问题描述

我正在尝试为一个项目创建美国地图。为此，我将d3.geoAlbersUsa()其用作投影和d3.geoPath(projection)路径功能。但是，当将“路径”附加到我的 svg 时，看起来“d”属性没有设置。

// Projection from geoAlbersUsa
let projection = d3.geoAlbersUsa()
                    .translate(width/2,height/2)
                    .scale(10000);

// Path from geoPath with the previous projection
let path = d3.geoPath().projection(projection);

let svg = d3.select("#svg");

// Load in csv and json data
d3.csv("state_results.csv", data => {
  d3.json("states.json", json => {

    // Process data from csv file and json file
    ...
    ...
    ...

    // Selecting 'g' element in svg and appending 'path'
    d3.select("#map").selectAll("path")
                .data(json.features)
                .enter()
                .append("path")
                .attr("d", path)
                .style("fill", d => {
                    return d.properties.party;
                });

当我启动我的服务器时，这就是我检查 svg 元素时显示的内容： 在此处输入图像描述

"d"关于为什么在每条路径中没有正确设置属性的任何想法？

下面是json.features数组中的一个元素： {"type":"Feature","id":"49","properties":{"name":"Utah","density":34.30},"geometry":{"type":"Polygon","coordinates":[[[-112.164359,41.995232],[-111.047063,42.000709],[-111.047063,40.998429],[-109.04798,40.998429],[-109.053457,39.125316],[-109.058934,38.27639],[-109.042503,38.166851],[-109.042503,37.000263],[-110.499369,37.00574],[-114.048427,37.000263],[-114.04295,41.995232],[-112.164359,41.995232]]]}},

标签： javascripthtmlsvgd3.jspath

解决方案

我已经使它与您提供的示例数据一起工作。您需要在 中的数字周围加上括号.translate([width / 2, height / 2])。除此之外，我只需要将比例缩小一点以使其适合屏幕。

const jsonFeatures = [{
  "type": "Feature",
  "id": "49",
  "properties": {
    "name": "Utah",
    "density": 34.30
  },
  "geometry": {
    "type": "Polygon",
    "coordinates": [
      [
        [-112.164359, 41.995232],
        [-111.047063, 42.000709],
        [-111.047063, 40.998429],
        [-109.04798, 40.998429],
        [-109.053457, 39.125316],
        [-109.058934, 38.27639],
        [-109.042503, 38.166851],
        [-109.042503, 37.000263],
        [-110.499369, 37.00574],
        [-114.048427, 37.000263],
        [-114.04295, 41.995232],
        [-112.164359, 41.995232]
      ]
    ]
  }
}];

let width = 500,
  height = 300;

// Projection from geoAlbersUsa
let projection = d3.geoAlbersUsa()
  .translate([width / 2, height / 2])
  .scale(1000);

// Path from geoPath with the previous projection
let path = d3.geoPath().projection(projection);

let svg = d3.select("svg").attr("width", width).attr("height", height);

svg.selectAll("path")
  .data(jsonFeatures)
  .enter()
  .append("path")
  .attr("d", path)
  .style("fill", d => {
    return d.properties.party;
  });
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.js"></script>
<svg></svg>

推荐阅读