proportionalSymbols = {
const svg = d3.create("svg")
.attr("viewBox", [0, 0, width, height]);
svg.append("path")
.datum(topojson.feature(basepolygons, basepolygons.objects.county))
.attr("fill", "#ccc")
.attr("d", path_basemap);
svg.append("path")
.datum(topojson.mesh(basepolygons, basepolygons.objects.county, (a, b) => a !== b))
.attr("fill", "none")
.attr("stroke", "white")
.attr("stroke-linejoin", "round")
.attr("d", path_basemap);
const legend = svg.append("g")
.attr("fill", "#777")
.attr("transform", "translate(100,600)")
.attr("text-anchor", "middle")
.style("font", "10px sans-serif")
.selectAll("g")
.data([10,40, d3.max([...data.values()])])
.join("g");
legend.append("circle")
.attr("fill", "none")
.attr("stroke", "#ccc")
.attr("cy", d => -radius(d))
.attr("r", radius);
legend.append("text")
.attr("y", d => -2 * radius(d))
.attr("dy", "1.3em")
.text(format);
svg.append("g")
.attr("fill", "#9DA4FB")
.attr("fill-opacity", 0.5)
.attr("stroke", "#7E85DD")
.attr("stroke-width", 0.5)
.selectAll("circle")
.data(points.features
.map(d => (d.value = data.get(d.properties.OBJECTID), d))
.sort((a, b) => b.value - a.value))
.join("circle")
.attr("transform", d => `translate(${path_points.centroid(d)})`)
.attr("r", d => radius(data.get(d.properties.OBJECTID)))
.append("title")
.text(d => `${d.properties.OBJECTID} : ${format(d.value)}`);
return svg.node();}
height = 700
width = 975
path_points = d3.geoPath().projection(projection)
path_basemap = d3.geoPath().projection(projection)
projection = d3.geoTransverseMercator().rotate([94,0]).fitExtent([[80, 80], [width, height]], counties);
counties = topojson.feature(basepolygons, basepolygons.objects.county)
format = d3.format(".2s")
radius(30)
d3.max([...data.values()])
radius(220)
//proportional symbols
radius = d3.scaleSqrt([0, d3.max([...data.values()])], [0, 30])
data.get(1)
data = Object.assign(new Map(csv_data))
csv_data = d3.csvParse(await FileAttachment("Iowa_Child_Care_Locations_and_Availability.csv").text(),({CENSE, CAPACITY, OPENINGS, OBJECTID}) => [+OBJECTID, +OPENINGS])
//import the point data (geojson)
points = FileAttachment("Iowa_Child_Care_Locations_and_Availability.json").json()
//import the polygon base map data
basepolygons = FileAttachment("counties_iowa_shipley.json").json()
simple = require("simple-statistics@7.0.7/dist/simple-statistics.min.js")
topojson = require("topojson-client@3")
d3 = require("d3@5")
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