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Caglar Koylu
Associate Professor of GIScience at the University of Iowa
Published
Edited
Feb 12, 2020
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md`# Attribute join by linking topojson with csv files
Median Age in Iowa Counties, Source: [Census 2010]`
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d3 = require("d3@5")
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import {legend} from "@d3/color-legend"
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format = d => `${d}%`
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topojson = require("topojson-client@3")
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iowa = FileAttachment("iowa_counties_topo.json").json()
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counties = topojson.feature(iowa, iowa.objects.iowa_counties)
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med_age = d3.csvParse(await FileAttachment("iowa_counties.csv").text(),({FIPS, MED_AGE}) => [FIPS, +MED_AGE])
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data = Object.assign(new Map(med_age), {title: "Median Age"})
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color = d3.scaleSequentialQuantile([...data.values()], d3.interpolateBlues)
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