Choropleth Map
Country-wise population data (2004)
Code
ChartUtil.tsx
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"use client";
// reference: https://d3-graph-gallery.com/graph/choropleth_hover_effect.html
import { ChartProps } from "@/types";
import React, { useRef, useCallback, useEffect } from "react";
import { useResizeObserver } from "@/hooks/useResizeObserver";
import * as d3 from "d3";
const ChartUtil = ({ data: { geoData, popData } }: ChartProps) => {
const containerRef = useRef<HTMLDivElement>(null);
const renderFunc = useCallback(() => {
const container = containerRef.current as HTMLElement;
if(!container) return;
const width = container.offsetWidth,
height = container.offsetWidth;
const svg = d3
.select(container)
.html("")
.append("svg")
.attr("width", width)
.attr("height", height);
// const path = d3.geoPath();
const projection: any = d3
.geoMercator()
.scale(width / 6.3333)
.center([0, 0])
.rotate([-12, 0])
.translate([width / 2, height / 2]);
const colors = d3.schemeBuPu[9];
const colorScale = d3.scaleThreshold(
[1e6, 5e6, 1e7, 5e7, 1e8, 5e8, 1e9, 5e9],
colors
);
const data = new Map();
popData.forEach((d: any) => {
data.set(d.code, +d.pop);
});
const tooltip = d3
.select(container)
.append("div")
.style("display", "none")
.attr("class", "tooltip")
.style("background-color", "#000")
.style("border", "solid")
.style("border-width", "2px")
.style("border-radius", "5px")
.style("padding", "5px")
.style("position", "absolute")
.style("color", "#fff");
let mouseOver = function (event: MouseEvent) {
tooltip.style("display", "block");
d3.selectAll(".Country").transition().duration(300).style("opacity", 0.5);
d3.select(event.target as SVGElement)
.transition()
.duration(0)
.style("opacity", 1)
.style("stroke", "#fff");
};
let mouseMove = function (event: MouseEvent, d: any) {
const tooltipNode = tooltip.node() as HTMLElement;
tooltip
.html(`${d.properties.name}:<br />${data.get(d.id) || 0}`)
.style("left", event.offsetX - tooltipNode.offsetWidth / 2 + "px")
.style("top", event.offsetY + 20 + "px");
};
let mouseLeave = function (event: MouseEvent, d: any) {
tooltip.style("display", "none");
d3.selectAll(".Country").transition().duration(0).style("opacity", 1);
d3.select(event.target as SVGElement)
.transition()
.duration(0)
.style("stroke", "transparent");
};
svg
.append("g")
.selectAll("path")
.data(geoData.features)
.enter()
.append("path")
// draw each country
.attr("d", (d: any) =>
(d3.geoPath().projection(projection)(d) ?? "").toString()
)
// set the color of each country
.attr("fill", function (d: any) {
d.total = data.get(d.id) || 0;
return colorScale(d.total);
})
.style("stroke", "transparent")
.attr("class", function (d) {
return "Country";
})
.style("opacity", 1)
.on("mouseover", mouseOver)
.on("mousemove", mouseMove)
.on("mouseleave", mouseLeave);
}, [geoData, popData]);
useEffect(() => {
containerRef.current !== null && renderFunc();
}, [renderFunc]);
const resizeHandler = useCallback(() => {
renderFunc();
}, [renderFunc]);
useResizeObserver(containerRef, resizeHandler);
return (
<>
<p className="text-center text-xl font-extralight font-sans">
Country-wise population data (2004)
</p>
<div className="relative" ref={containerRef}></div>
</>
);
};
export default ChartUtil;