Historian of early America, Indigenous history, and material culture
chart = {
let transform = d3.zoomIdentity; //ZOOM
const links = data.links.map(d => Object.create(d));
const nodes = data.nodes.map(d => Object.create(d));
const simulation = d3
.forceSimulation(nodes)
.force("link", d3.forceLink(links).id(d => d.id))
.force("charge", d3.forceManyBody())
.force("center", d3.forceCenter(width / 2, height / 2))
.force("collision", d3.forceCollide(d => d.degree + 2));
const svg = d3
.create("svg")
.attr("height", height)
.attr("width", width);
const link = svg
.append("g")
.attr("stroke", "#999")
.attr("stroke-opacity", 0.6)
.selectAll("line")
.data(links)
.join("line")
.attr("stroke-width", d => Math.sqrt(d.value));
const node = svg
.append("g")
.attr("stroke", "#fff")
.attr("stroke-width", 1.5)
.selectAll("circle")
.data(nodes)
.join("circle")
.attr("r", d => d.degree + 2)
.attr("fill", color)
.call(drag(simulation));
const textElems = svg
.append('g')
.selectAll('text')
.data(nodes)
.join('text')
.text(d => d.id)
.attr('font-size', 12)
.call(drag(simulation));
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);
textElems
.attr("x", d => d.x + 10)
.attr("y", d => d.y)
.attr("visibility", function(d) {
if (d.degree >= 10) {
return "visible";
} else {
return "hidden";
}
});
});
//ZOOM
const zoomRect = svg
.append("rect")
.attr("width", width)
.attr("height", height)
.style("fill", "none")
.style("pointer-events", "all");
//ZOOM
const zoom = d3
.zoom()
.scaleExtent([1 / 2, 64])
.on("zoom", zoomed);
//ZOOM
zoomRect.call(zoom).call(zoom.translateTo, width / 2, height / 2);
//ZOOM
function zoomed() {
transform = d3.event.transform;
node.attr("transform", d3.event.transform);
link.attr("transform", d3.event.transform);
textElems.attr("transform", d3.event.transform);
}
return svg.node();
}
md`## Get the data file`
data = FileAttachment("graph.json").json() // network data is almost always encoded in
// json format, so we tell Observable to read the data file
// as json
md`## Define slider`
import { Range } from "@observablehq/inputs"
// define the minimum start year by getting the min of the birth years
start_year = d3.min(data.nodes, d => +d.birth_year)
end_year = d3.max(data.nodes, d => +d.death_year)
numberOfYears = end_year - start_year
timeScale = d3
.scaleLinear()
.domain([start_year, end_year])
.range([0, numberOfYears])
date = year_slider
viewof year_slider = Range([start_year, end_year], { step: 1, label: "Year" })
md`The slider is showing ${date}`
md `## Show and remove links and nodes based on year`
showLinkLines => {
var filterId = [];
var allLines = svg.selectAll('line');
var allNodes = svg.selectAll('circle');
// loop over each node, and update color attribute
allLines.style("stroke-opacity", function(d, i) {
return d.year <= parseInt(date) ? 0.7 : 0;
});
allLines.exit().remove();
allNodes.style('opacity', function(d, i) {
return d.year <= parseInt(date) ? 1 : 0;
});
allNodes.exit().remove();
}
md`## Define height`
height = 600
md`## Define the color scale`
color = {
const scale = d3.scaleOrdinal(d3.schemeCategory10);
return d => scale(d.modularity);
}
md`## Handle dragging`
drag = simulation => {
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;
}
return d3
.drag()
.on("start", dragstarted)
.on("drag", dragged)
.on("end", dragended);
}
md`### Include D3`
d3 = require("d3@5")
Purpose-built for displays of data
Observable is your go-to platform for exploring data and creating expressive data visualizations. Use reactive JavaScript notebooks for prototyping and a collaborative canvas for visual data exploration and dashboard creation.
