Associate Professor of GIScience at the University of Iowa
Published
Edited
Apr 10, 2020
1 fork
labels = ["low", "", "high"]
n = Math.floor(Math.sqrt(colors.length))
x = d3.scaleQuantile(Array.from(data.values(), d => d[0]), d3.range(n))
y = d3.scaleQuantile(Array.from(data.values(), d => d[1]), d3.range(n))
path = d3.geoPath().projection(projection)
//Rotate the map sets the longitude of origin for our UTM projection.
projection = d3.geoTransverseMercator()
.rotate([93, 0])
.center([0, 62])
.fitExtent([[80, 80], [width, height]], polygon_features);
polygon_features = topojson.feature(polygons, polygons.objects.LouisianaGEO)
data = Object.assign(new Map(d3.csvParse(await FileAttachment("Louisiana.csv").text(), ({NAME, BLACK, FHH_CHILD, POP2010}) => [NAME, [+FHH_CHILD, 100 * +BLACK/+POP2010]])), {title: ["Single Mother Households", "% Black"]})
idAttribute = "NAME"
polygons = FileAttachment("LouisianaTOPO.json").json()
height = 550
width = 875
legend = () => {
const k = 24;
const arrow = DOM.uid();
return svg`<g font-family=sans-serif font-size=10>
<g transform="translate(-${k * n / 2},-${k * n / 2}) rotate(-45 ${k * n / 2},${k * n / 2})">
<marker id="${arrow.id}" markerHeight=10 markerWidth=10 refX=6 refY=3 orient=auto>
<path d="M0,0L9,3L0,6Z" />
</marker>
${d3.cross(d3.range(n), d3.range(n)).map(([i, j]) => svg`<rect width=${k} height=${k} x=${i * k} y=${(n - 1 - j) * k} fill=${colors[j * n + i]}>
<title>${data.title[0]}${labels[j] && ` (${labels[j]})`}
${data.title[1]}${labels[i] && ` (${labels[i]})`}</title>
</rect>`)}
<line marker-end="${arrow}" x1=0 x2=${n * k} y1=${n * k} y2=${n * k} stroke=black stroke-width=1.5 />
<line marker-end="${arrow}" y2=0 y1=${n * k} stroke=black stroke-width=1.5 />
<text font-weight="bold" dy="0.71em" transform="rotate(90) translate(${n / 2 * k},6)" text-anchor="middle">${data.title[0]}</text>
<text font-weight="bold" dy="0.71em" transform="translate(${n / 2 * k},${n * k + 6})" text-anchor="middle">${data.title[1]}</text>
</g>
</g>`;
}
color = {
return value => {
if (!value) return "#ccc";
let [a, b] = value;
return colors[y(b) + x(a) * n];
};
}
formatNum = d3.format(".1f")
format = (value) => {
if (!value) return "N/A";
let [a, b] = value;
return `${a} ${data.title[0]}${labels[x(a)] && ` (${labels[x(a)]})`}
${formatNum(b)} ${data.title[1]}${labels[y(b)] && ` (${labels[y(b)]})`}`;
}
topojson = require("topojson-client@3")
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.
