d3=require("d3@5")
topojson=require("topojson-client@3")
BasePolygons = FileAttachment("iowa_borderWGS84.json").json()
points = FileAttachment("City_Park_Locations.json").json()
csv_data = d3.csvParse(await FileAttachment("City_Park_Locations.csv").text(),({NAME, Shape__Are}) => [NAME, +Shape__Are])
data = Object.assign(new Map(csv_data))
data.get("Ashby Park")
radius = d3.scaleSqrt([0, d3.max([...data.values()])], [0, 20])
radius(5363075.53259277)
d3.max([...data.values()])
format = d3.format(",.0f")
projection = d3.geoTransverseMercator().rotate([94,0]).fitExtent([[150, 150], [width, height]], points)
path_basemap = d3.geoPath().projection(projection)
path_points = d3.geoPath().projection(projection)
proportionalsymbols = {
const svg = d3.create("svg")
.attr("viewBox", [70, 70, width, height]);
svg.append("path")
.datum(topojson.feature(BasePolygons, BasePolygons.objects.iowa_borderWGS84))
.attr("fill", "#f0f0f0")
.attr("stroke", "black")
.attr("d", path_basemap);
svg.append("path")
.datum(topojson.mesh(BasePolygons, BasePolygons.objects.iowa_borderWGS84, (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", "black")
.attr("transform", "translate(950,600)")
//this is the x y coordinates of the legend
.attr("text-anchor", "middle")
.style("font", "12px sans-serif")
.selectAll("g")
//you can also add more circles here if you want
.data([1.4e7, d3.max([...data.values()])])
//this is your legends max and minimum value, we will have to change it
.join("g");
legend.append("circle")
.attr("fill", "none")
.attr("stroke", "black")
.attr("cy", d => -radius(d))
.attr("r", radius);
legend.append("text")
.attr("y", d => -3.2 * radius(d))
.attr("dy", "1.4cm")
.text(d3.format(".2s"));
svg.append("g")
.attr("fill", "#99d8c9")
.attr("fill-opacity", 0.35)
.attr("stroke", "#00441b")
.attr("stroke-width", 0.25)
.selectAll("circle")
.data(points.features
.map(d => (d.value = data.get(d.properties.NAME), d))
.sort((a, b) => b.value - a.value))
//displays larger circles in the back
.join("circle")
.attr("transform", d => `translate(${path_points.centroid(d)})`)
.attr("r", d => radius(data.get(d.properties.NAME)))
.append("title")
.text(d => `${d.properties.NAME} : ${format(d.value)}`);
return svg.node();
}
width = 975
height = 610
margin = 0
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.
