d3-viz

D3.js 可视化

概述

此技能提供了使用 d3.js 创建精巧交互式数据可视化的指南。D3.js（Data-Driven Documents）擅长将数据绑定到 DOM 元素，并应用数据驱动的转换来创建自定义的出版级可视化，从而精确控制每个视觉元素。这些技术适用于任何 JavaScript 环境，包括原生 JavaScript、React、Vue、Svelte 和其他框架。

何时使用 d3.js

适用于以下场景：

• 需要独特视觉编码或布局的自定义可视化
• 具有复杂平移、缩放或刷选行为的交互式探索
• 网络／图可视化（力导向布局、树图、层级结构、弦图）
• 使用自定义投影的地理可视化
• 需要流畅、精心编排的过渡效果的可视化
• 需要精细样式控制的出版级图形
• 标准库中没有的新型图表

可考虑以下替代方案：

• 3D 可视化——改用 Three.js

核心工作流

1. 设置 d3.js

在脚本顶部导入 d3：

import * as d3 from 'd3';

或者使用 CDN 版本（7.x）：

<script src="https://d3js.org/d3.v7.min.js"></script>

所有模块（比例尺、坐标轴、图形、过渡等）都可通过 d3 命名空间访问。

2. 选择集成模式

模式 A：直接操作 DOM（大多数情况下推荐） 使用 d3 选择 DOM 元素并以命令式方式操作。这适用于任何 JavaScript 环境：

function drawChart(data) {
  if (!data || data.length === 0) return;

  const svg = d3.select('#chart'); // Select by ID, class, or DOM element

  // Clear previous content
  svg.selectAll("*").remove();

  // Set up dimensions
  const width = 800;
  const height = 400;
  const margin = { top: 20, right: 30, bottom: 40, left: 50 };

  // Create scales, axes, and draw visualisation
  // ... d3 code here ...
}

// Call when data changes
drawChart(myData);

模式 B：声明式渲染（适用于带模板的框架） 使用 d3 进行数据计算（比例尺、布局），但通过框架渲染元素：

function getChartElements(data) {
  const xScale = d3.scaleLinear()
    .domain([0, d3.max(data, d => d.value)])
    .range([0, 400]);

  return data.map((d, i) => ({
    x: 50,
    y: i * 30,
    width: xScale(d.value),
    height: 25
  }));
}

// In React: {getChartElements(data).map((d, i) => <rect key={i} {...d} fill="steelblue" />)}
// In Vue: v-for directive over the returned array
// In vanilla JS: Create elements manually from the returned data

对于具有过渡、交互效果或需要充分利用 d3 功能的复杂可视化，使用模式 A。对于较简单的可视化，或框架更适合声明式渲染的情况，使用模式 B。

3. 组织可视化代码

在绘图函数中遵循以下标准结构：

function drawVisualization(data) {
  if (!data || data.length === 0) return;

  const svg = d3.select('#chart'); // Or pass a selector/element
  svg.selectAll("*").remove(); // Clear previous render

  // 1. Define dimensions
  const width = 800;
  const height = 400;
  const margin = { top: 20, right: 30, bottom: 40, left: 50 };
  const innerWidth = width - margin.left - margin.right;
  const innerHeight = height - margin.top - margin.bottom;

  // 2. Create main group with margins
  const g = svg.append("g")
    .attr("transform", `translate(${margin.left},${margin.top})`);

  // 3. Create scales
  const xScale = d3.scaleLinear()
    .domain([0, d3.max(data, d => d.x)])
    .range([0, innerWidth]);

  const yScale = d3.scaleLinear()
    .domain([0, d3.max(data, d => d.y)])
    .range([innerHeight, 0]); // Note: inverted for SVG coordinates

  // 4. Create and append axes
  const xAxis = d3.axisBottom(xScale);
  const yAxis = d3.axisLeft(yScale);

  g.append("g")
    .attr("transform", `translate(0,${innerHeight})`)
    .call(xAxis);

  g.append("g")
    .call(yAxis);

  // 5. Bind data and create visual elements
  g.selectAll("circle")
    .data(data)
    .join("circle")
    .attr("cx", d => xScale(d.x))
    .attr("cy", d => yScale(d.y))
    .attr("r", 5)
    .attr("fill", "steelblue");
}

// Call when data changes
drawVisualization(myData);

4. 实现响应式尺寸

使可视化能够适应容器尺寸：

function setupResponsiveChart(containerId, data) {
  const container = document.getElementById(containerId);
  const svg = d3.select(`#${containerId}`).append('svg');

  function updateChart() {
    const { width, height } = container.getBoundingClientRect();
    svg.attr('width', width).attr('height', height);

    // Redraw visualisation with new dimensions
    drawChart(data, svg, width, height);
  }

  // Update on initial load
  updateChart();

  // Update on window resize
  window.addEventListener('resize', updateChart);

  // Return cleanup function
  return () => window.removeEventListener('resize', updateChart);
}

// Usage:
// const cleanup = setupResponsiveChart('chart-container', myData);
// cleanup(); // Call when component unmounts or element removed

或者使用 ResizeObserver 更直接地监控容器：

function setupResponsiveChartWithObserver(svgElement, data) {
  const observer = new ResizeObserver(() => {
    const { width, height } = svgElement.getBoundingClientRect();
    d3.select(svgElement)
      .attr('width', width)
      .attr('height', height);

    // Redraw visualisation
    drawChart(data, d3.select(svgElement), width, height);
  });

  observer.observe(svgElement.parentElement);
  return () => observer.disconnect();
}

常见可视化模式

条形图

function drawBarChart(data, svgElement) {
  if (!data || data.length === 0) return;

  const svg = d3.select(svgElement);
  svg.selectAll("*").remove();

  const width = 800;
  const height = 400;
  const margin = { top: 20, right: 30, bottom: 40, left: 50 };
  const innerWidth = width - margin.left - margin.right;
  const innerHeight = height - margin.top - margin.bottom;

  const g = svg.append("g")
    .attr("transform", `translate(${margin.left},${margin.top})`);

  const xScale = d3.scaleBand()
    .domain(data.map(d => d.category))
    .range([0, innerWidth])
    .padding(0.1);

  const yScale = d3.scaleLinear()
    .domain([0, d3.max(data, d => d.value)])
    .range([innerHeight, 0]);

  g.append("g")
    .attr("transform", `translate(0,${innerHeight})`)
    .call(d3.axisBottom(xScale));

  g.append("g")
    .call(d3.axisLeft(yScale));

  g.selectAll("rect")
    .data(data)
    .join("rect")
    .attr("x", d => xScale(d.category))
    .attr("y", d => yScale(d.value))
    .attr("width", xScale.bandwidth())
    .attr("height", d => innerHeight - yScale(d.value))
    .attr("fill", "steelblue");
}

// Usage:
// drawBarChart(myData, document.getElementById('chart'));

折线图

const line = d3.line()
  .x(d => xScale(d.date))
  .y(d => yScale(d.value))
  .curve(d3.curveMonotoneX); // Smooth curve

g.append("path")
  .datum(data)
  .attr("fill", "none")
  .attr("stroke", "steelblue")
  .attr("stroke-width", 2)
  .attr("d", line);

散点图

g.selectAll("circle")
  .data(data)
  .join("circle")
  .attr("cx", d => xScale(d.x))
  .attr("cy", d => yScale(d.y))
  .attr("r", d => sizeScale(d.size)) // Optional: size encoding
  .attr("fill", d => colourScale(d.category)) // Optional: colour encoding
  .attr("opacity", 0.7);

弦图

弦图以圆形布局展示实体之间的关系，并用带状图形表示它们之间的流动：

function drawChordDiagram(data) {
  // data format: array of objects with source, target, and value
  // Example: [{ source: 'A', target: 'B', value: 10 }, ...]

  if (!data || data.length === 0) return;

  const svg = d3.select('#chart');
  svg.selectAll("*").remove();

  const width = 600;
  const height = 600;
  const innerRadius = Math.min(width, height) * 0.3;
  const outerRadius = innerRadius + 30;

  // Create matrix from data
  const nodes = Array.from(new Set(data.flatMap(d => [d.source, d.target])));
  const matrix = Array.from({ length: nodes.length }, () => Array(nodes.length).fill(0));

  data.forEach(d => {
    const i = nodes.indexOf(d.source);
    const j = nodes.indexOf(d.target);
    matrix[i][j] += d.value;
    matrix[j][i] += d.value;
  });

  // Create chord layout
  const chord = d3.chord()
    .padAngle(0.05)
    .sortSubgroups(d3.descending);

  const arc = d3.arc()
    .innerRadius(innerRadius)
    .outerRadius(outerRadius);

  const ribbon = d3.ribbon()
    .source(d => d.source)
    .target(d => d.target);

  const colourScale = d3.scaleOrdinal(d3.schemeCategory10)
    .domain(nodes);

  const g = svg.append("g")
    .attr("transform", `translate(${width / 2},${height / 2})`);

  const chords = chord(matrix);

  // Draw ribbons
  g.append("g")
    .attr("fill-opacity", 0.67)
    .selectAll("path")
    .data(chords)
    .join("path")
    .attr("d", ribbon)
    .attr("fill", d => colourScale(nodes[d.source.index]))
    .attr("stroke", d => d3.rgb(colourScale(nodes[d.source.index])).darker());

  // Draw groups (arcs)
  const group = g.append("g")
    .selectAll("g")
    .data(chords.groups)
    .join("g");

  group.append("path")
    .attr("d", arc)
    .attr("fill", d => colourScale(nodes[d.index]))
    .attr("stroke", d => d3.rgb(colourScale(nodes[d.index])).darker());

  // Add labels
  group.append("text")
    .each(d => { d.angle = (d.startAngle + d.endAngle) / 2; })
    .attr("dy", "0.31em")
    .attr("transform", d => `rotate(${(d.angle * 180 / Math.PI) - 90})translate(${outerRadius + 30})${d.angle > Math.PI ? "rotate(180)" : ""}`)
    .attr("text-anchor", d => d.angle > Math.PI ? "end" : null)
    .text((d, i) => nodes[i])
    .style("font-size", "12px");
}

热力图

热力图使用颜色在二维网格中编码数值，适用于展示不同类别之间的模式：

function drawHeatmap(data) {
  // data format: array of objects with row, column, and value
  // Example: [{ row: 'A', column: 'X', value: 10 }, ...]

  if (!data || data.length === 0) return;

  const svg = d3.select('#chart');
  svg.selectAll("*").remove();

  const width = 800;
  const height = 600;
  const margin = { top: 100, right: 30, bottom: 30, left: 100 };
  const innerWidth = width - margin.left - margin.right;
  const innerHeight = height - margin.top - margin.bottom;

  // Get unique rows and columns
  const rows = Array.from(new Set(data.map(d => d.row)));
  const columns = Array.from(new Set(data.map(d => d.column)));

  const g = svg.append("g")
    .attr("transform", `translate(${margin.left},${margin.top})`);

  // Create scales
  const xScale = d3.scaleBand()
    .domain(columns)
    .range([0, innerWidth])
    .padding(0.01);

  const yScale = d3.scaleBand()
    .domain(rows)
    .range([0, innerHeight])
    .padding(0.01);

  // Colour scale for values
  const colourScale = d3.scaleSequential(d3.interpolateYlOrRd)
    .domain([0, d3.max(data, d => d.value)]);

  // Draw rectangles
  g.selectAll("rect")
    .data(data)
    .join("rect")
    .attr("x", d => xScale(d.column))
    .attr("y", d => yScale(d.row))
    .attr("width", xScale.bandwidth())
    .attr("height", yScale.bandwidth())
    .attr("fill", d => colourScale(d.value));

  // Add x-axis labels
  svg.append("g")
    .attr("transform", `translate(${margin.left},${margin.top})`)
    .selectAll("text")
    .data(columns)
    .join("text")
    .attr("x", d => xScale(d) + xScale.bandwidth() / 2)
    .attr("y", -10)
    .attr("text-anchor", "middle")
    .text(d => d)
    .style("font-size", "12px");

  // Add y-axis labels
  svg.append("g")
    .attr("transform", `translate(${margin.left},${margin.top})`)
    .selectAll("text")
    .data(rows)
    .join("text")
    .attr("x", -10)
    .attr("y", d => yScale(d) + yScale.bandwidth() / 2)
    .attr("dy", "0.35em")
    .attr("text-anchor", "end")
    .text(d => d)
    .style("font-size", "12px");

  // Add colour legend
  const legendWidth = 20;
  const legendHeight = 200;
  const legend = svg.append("g")
    .attr("transform", `translate(${width - 60},${margin.top})`);

  const legendScale = d3.scaleLinear()
    .domain(colourScale.domain())
    .range([legendHeight, 0]);

  const legendAxis = d3.axisRight(legendScale)
    .ticks(5);

  // Draw colour gradient in legend
  for (let i = 0; i < legendHeight; i++) {
    legend.append("rect")
      .attr("y", i)
      .attr("width", legendWidth)
      .attr("height", 1)
      .attr("fill", colourScale(legendScale.invert(i)));
  }

  legend.append("g")
    .attr("transform", `translate(${legendWidth},0)`)
    .call(legendAxis);
}

饼图

const pie = d3.pie()
  .value(d => d.value)
  .sort(null);

const arc = d3.arc()
  .innerRadius(0)
  .outerRadius(Math.min(width, height) / 2 - 20);

const colourScale = d3.scaleOrdinal(d3.schemeCategory10);

const g = svg.append("g")
  .attr("transform", `translate(${width / 2},${height / 2})`);

g.selectAll("path")
  .data(pie(data))
  .join("path")
  .attr("d", arc)
  .attr("fill", (d, i) => colourScale(i))
  .attr("stroke", "white")
  .attr("stroke-width", 2);

力导向网络图

const simulation = d3.forceSimulation(nodes)
  .force("link", d3.forceLink(links).id(d => d.id).distance(100))
  .force("charge", d3.forceManyBody().strength(-300))
  .force("center", d3.forceCenter(width / 2, height / 2));

const link = g.selectAll("line")
  .data(links)
  .join("line")
  .attr("stroke", "#999")
  .attr("stroke-width", 1);

const node = g.selectAll("circle")
  .data(nodes)
  .join("circle")
  .attr("r", 8)
  .attr("fill", "steelblue")
  .call(d3.drag()
    .on("start", dragstarted)
    .on("drag", dragged)
    .on("end", dragended));

simulation.on("tick", () => {
  link
    .attr("x1", d => d.source.x)
    .attr("y1", d => d.source.y)
    .attr("x2", d => d.target.x)
    .attr("y2", d => d.target.y);
  
  node
    .attr("cx", d => d.x)
    .attr("cy", d => d.y);
});

function dragstarted(event) {
  if (!event.active) simulation.alphaTarget(0.3).restart();
  event.subject.fx = event.subject.x;
  event.subject.fy = event.subject.y;
}

function dragged(event) {
  event.subject.fx = event.x;
  event.subject.fy = event.y;
}

function dragended(event) {
  if (!event.active) simulation.alphaTarget(0);
  event.subject.fx = null;
  event.subject.fy = null;
}

添加交互性

工具提示

// Create tooltip div (outside SVG)
const tooltip = d3.select("body").append("div")
  .attr("class", "tooltip")
  .style("position", "absolute")
  .style("visibility", "hidden")
  .style("background-color", "white")
  .style("border", "1px solid #ddd")
  .style("padding", "10px")
  .style("border-radius", "4px")
  .style("pointer-events", "none");

// Add to elements
circles
  .on("mouseover", function(event, d) {
    d3.select(this).attr("opacity", 1);
    tooltip
      .style("visibility", "visible")
      .html(`<strong>${d.label}</strong><br/>Value: ${d.value}`);
  })
  .on("mousemove", function(event) {
    tooltip
      .style("top", (event.pageY - 10) + "px")
      .style("left", (event.pageX + 10) + "px");
  })
  .on("mouseout", function() {
    d3.select(this).attr("opacity", 0.7);
    tooltip.style("visibility", "hidden");
  });

缩放和平移

const zoom = d3.zoom()
  .scaleExtent([0.5, 10])
  .on("zoom", (event) => {
    g.attr("transform", event.transform);
  });

svg.call(zoom);

点击交互

circles
  .on("click", function(event, d) {
    // Handle click (dispatch event, update app state, etc.)
    console.log("Clicked:", d);

    // Visual feedback
    d3.selectAll("circle").attr("fill", "steelblue");
    d3.select(this).attr("fill", "orange");

    // Optional: dispatch custom event for your framework/app to listen to
    // window.dispatchEvent(new CustomEvent('chartClick', { detail: d }));
  });

过渡与动画

为视觉变化添加平滑的过渡效果：

// Basic transition
circles
  .transition()
  .duration(750)
  .attr("r", 10);

// Chained transitions
circles
  .transition()
  .duration(500)
  .attr("fill", "orange")
  .transition()
  .duration(500)
  .attr("r", 15);

// Staggered transitions
circles
  .transition()
  .delay((d, i) => i * 50)
  .duration(500)
  .attr("cy", d => yScale(d.value));

// Custom easing
circles
  .transition()
  .duration(1000)
  .ease(d3.easeBounceOut)
  .attr("r", 10);

比例尺参考

定量比例尺

// Linear scale
const xScale = d3.scaleLinear()
  .domain([0, 100])
  .range([0, 500]);

// Log scale (for exponential data)
const logScale = d3.scaleLog()
  .domain([1, 1000])
  .range([0, 500]);

// Power scale
const powScale = d3.scalePow()
  .exponent(2)
  .domain([0, 100])
  .range([0, 500]);

// Time scale
const timeScale = d3.scaleTime()
  .domain([new Date(2020, 0, 1), new Date(2024, 0, 1)])
  .range([0, 500]);

序数比例尺

// Band scale (for bar charts)
const bandScale = d3.scaleBand()
  .domain(['A', 'B', 'C', 'D'])
  .range([0, 400])
  .padding(0.1);

// Point scale (for line/scatter categories)
const pointScale = d3.scalePoint()
  .domain(['A', 'B', 'C', 'D'])
  .range([0, 400]);

// Ordinal scale (for colours)
const colourScale = d3.scaleOrdinal(d3.schemeCategory10);

连续比例尺

// Sequential colour scale
const colourScale = d3.scaleSequential(d3.interpolateBlues)
  .domain([0, 100]);

// Diverging colour scale
const divScale = d3.scaleDiverging(d3.interpolateRdBu)
  .domain([-10, 0, 10]);

最佳实践

数据准备

可视化之前，始终验证并准备数据：

// Filter invalid values
const cleanData = data.filter(d => d.value != null && !isNaN(d.value));

// Sort data if order matters
const sortedData = [...data].sort((a, b) => b.value - a.value);

// Parse dates
const parsedData = data.map(d => ({
  ...d,
  date: d3.timeParse("%Y-%m-%d")(d.date)
}));

性能优化

对于大型数据集（>1000 个元素）：

// Use canvas instead of SVG for many elements
// Use quadtree for collision detection
// Simplify paths with d3.line().curve(d3.curveStep)
// Implement virtual scrolling for large lists
// Use requestAnimationFrame for custom animations

无障碍性

确保可视化易于访问：

// Add ARIA labels
svg.attr("role", "img")
   .attr("aria-label", "Bar chart showing quarterly revenue");

// Add title and description
svg.append("title").text("Quarterly Revenue 2024");
svg.append("desc").text("Bar chart showing revenue growth across four quarters");

// Ensure sufficient colour contrast
// Provide keyboard navigation for interactive elements
// Include data table alternative

样式

使用一致、专业的样式：

// Define colour palettes upfront
const colours = {
  primary: '#4A90E2',
  secondary: '#7B68EE',
  background: '#F5F7FA',
  text: '#333333',
  gridLines: '#E0E0E0'
};

// Apply consistent typography
svg.selectAll("text")
  .style("font-family", "Inter, sans-serif")
  .style("font-size", "12px");

// Use subtle grid lines
g.selectAll(".tick line")
  .attr("stroke", colours.gridLines)
  .attr("stroke-dasharray", "2,2");

常见问题和解决方案

问题：坐标轴未显示

• 确保比例尺具有有效的定义域（检查是否存在 NaN 值）
• 确认坐标轴已添加到正确的组
• 检查变换平移是否正确

问题：过渡效果不起作用

• 在更改属性前调用 .transition()
• 确保元素具有唯一键，以便正确绑定数据
• 检查 useEffect 依赖项是否包含所有变化的数据

问题：响应式尺寸调整不起作用

• 使用 ResizeObserver 或 window resize 监听器
• 在状态中更新尺寸以触发重新渲染
• 确保 SVG 具有 width/height 属性或 viewBox

问题：性能问题

• 限制 DOM 元素数量（对于超过 1000 个项目，可考虑使用 canvas）
• 对 resize 处理程序进行防抖
• 使用 .join()，而不是分别进行 enter/update/exit 选择
• 通过检查依赖项避免不必要的重新渲染

资源

references/

包含详细的参考资料：

• d3-patterns.md - 可视化模式和代码示例的综合集合
• scale-reference.md - D3 比例尺完整指南，附带示例
• colour-schemes.md - D3 配色方案和调色板建议

assets/

包含样板模板：

• chart-template.js - 基本图表的入门模板
• interactive-template.js - 包含工具提示、缩放和交互的模板
• sample-data.json - 用于测试的示例数据集

这些模板适用于原生 JavaScript、React、Vue、Svelte 或任何其他 JavaScript 环境。请根据特定框架按需调整。

如需针对特定可视化类型或模式获取详细指导，请阅读相关文件以使用这些资源。