county_data = d3.csv(
"https://raw.githubusercontent.com/nytimes/covid-19-data/master/us-counties.csv"
)
render_data_table(county_data.slice(0, 10))
md`This is the dataset of the covid-19 cases of each counties in the United States`
county_data1 = county_data.filter(d => d.date === "2020-05-10")
county_map = Object.assign(new Map(county_data1.map(d => [d.fips, +d.cases])))
data = Object.assign(new Map(county_data1.map(d => [d.fips, +d.cases])), {
title: "Covid-19 Cases"
})
color_scale = d3.scaleSequential(
d3.extent(county_map, d => d.cases),
d3.interpolateBuPu
)
color = d3.scaleQuantize([1, 1000], d3.schemeReds[9])
md`## Bubble Map`
import { chart as bubbleMap, radius } with {
county_map as data
} from '@d3/bubble-map'
bubbleMap
md`Bubble Map has the advantage of showing the distribution of data more effectively, especially displaying the scale of the data and the data that has relatively large scale. But when it comes to displaying small scale of the data, it might not deliver accurate data.`
md`## Choropleth Map`
chart = {
const svg = d3.create("svg").attr("viewBox", [0, 0, 975, 610]);
svg
.append("g")
.attr("transform", "translate(610,20)")
.append(() => legend({ color, title: data.title, width: 260 }));
svg
.append("g")
.selectAll("path")
.data(topojson.feature(us, us.objects.counties).features)
.join("path")
.attr("fill", d => color(data.get(d.id)))
.attr("d", path)
.append("title")
.text(
d => `${d.properties.name}, ${states.get(d.id.slice(0, 2)).name}
${format(data.get(d.id))}`
);
return svg.node();
}
format = d => `${d}`
md`The Choropleth Map can display the trend and separated scales by colors effectively, but when it comes to large data scales, it might not deliver accurate information effectively.`
md`The usage of format is confusing and I'm not sure about its rules.`
us = FileAttachment("counties-albers-10m.json").json()
topojson = require("topojson-client@3")
d3 = require("d3@5")
path = d3.geoPath()
states = new Map(us.objects.states.geometries.map(d => [d.id, d.properties]))
import { legend } from "@d3/color-legend"
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