I'm a professor of mathematics at the University of North Carolina Asheville. I've also done a fair amount of consulting work over the years focusing on scientific and data visualization.
I'm happy to be part of the first Observable Ambassador's cohort.
Public
Edited
Jun 30, 2023
1 fork
1 star
NC Congressional DistrictsTrivariate choropleth for racial composition in the USRacial distribution in NCWNC Zoom3D Choropleth for NC County PopulationsNC CountiesTriangulated Canadian Provinces (separate)Triangulated NC CountiesAn X3D GlobeCanadian Elections 3DWNC SurroundElectoral Results TilegramThe new Electoral CollegeElectoral MapGPX rides with Leaflet and OSMOld encoded polyline rides with LeafletGPX rides with Maplibre and MaptilerBuncombe county votingHexapolis 538Zillow Home PricesSetting up HexapolisCOVID curvesThirty day Map Challenge - Day 1Simple grid cartogram2020 Census Apportionment TilegramMass shootings in the USHBCUsNC State Legislative Elections 2022Hierarchical Structure of the US RegionsIndigenous territories of the SoutheastD3.force to desired positionPopulation Choropleth for the Contiguous US StatesPlotting a few points on a mapMutliple bubble maps for CSV dataWorld population bubble mapReproductive rights and ... ??Gerrymandering Hexapolis by handVisualizations of gun ownership dataIncome inequality in North Carolina
The NC Congressional redistricting battle
Also listed in…
Political Issues
function make_boundaries(boundaries) {
let svg = d3.create("svg").attr("width", w).attr("height", h);
let map = svg.append("g");
map
.append("g")
.selectAll("path.boundary")
.data(boundaries.features)
.join("path")
.attr("class", "boundary")
.attr("data-district_votes", function (o) {
return `${o.properties.district}-${o.properties.dem_vote}-${o.properties.rep_vote}`;
})
.attr("fill", "white")
.attr("fill-opacity", 0)
.attr("stroke", "#333")
.attr("stroke-width", 2)
.attr("stroke-linejoin", "round")
.attr("d", path)
.on("pointerenter", function () {
d3.selectAll("path.boundary").attr("fill-opacity", 0.4);
d3.select(this).attr("fill-opacity", 0).attr("stroke-width", 5).raise();
})
.on("pointerleave", function () {
d3.selectAll("path.boundary")
.attr("fill-opacity", 0)
.attr("stroke-width", 2);
});
map
.append("g")
.selectAll("circle.city")
.data(cities)
.join("circle")
.attr("class", "city")
.attr("cx", (o) => o.x)
.attr("cy", (o) => o.y)
.attr("r", 4)
.attr("fill", "black")
.attr("stroke", "white")
.attr("stroke-width", 2)
.attr("pointer-events", "none");
let city_background_container = map
.append("g")
.attr("id", "city_background_container");
let city_name_display = map.append("g");
city_name_display
.selectAll("text.city")
.data(cities)
.join("text")
.attr("class", "city")
.attr("x", (o) => o.x)
.attr("y", (o) => o.y)
.attr("dx", (o) => (o.city == "Winston-Salem" ? (-90 * width) / 1100 : 3))
.attr("dy", (o) => (o.city == "Winston-Salem" ? (-15 * width) / 1100 : -3))
.attr("opacity", show_cities ? 1 : 0)
.text((o) => o.city)
.style("font-family", "sans-serif")
.attr("font-size", (14 * width) / 1100)
.attr("pointer-events", "none");
map
.selectAll("path.boundary")
.nodes()
.forEach(function (d, i) {
let [district, dem, rep] = d
.getAttribute("data-district_votes")
.split("-")
.map((x) => parseInt(x));
let total = dem + rep;
let dprop = dem / total;
let rprop = rep / total;
let dpct = d3.format("0.1%")(dem / total);
let rpct = d3.format("0.1%")(rep / total);
let lean;
if (dprop < rprop) {
lean = `R +${d3.format("0.1%")(rprop - state_dem_proportion)}`;
} else {
lean = `D +${d3.format("0.1%")(dprop - state_dem_proportion)}`;
}
let content = `
<div>
<div>
<div style="display: inline-block; margin-right: 5px">
District: ${district}
</div>
<div style="display: inline-block">
Lean: ${lean}
</div>
</div>
</div>`;
tippy(d, {
content: content,
allowHTML: true,
theme: "light-border",
followCursor: true
});
});
return svg.node();
}
// viewof show_cities = Inputs.toggle({ label: "Show city labels:" })
// This was a toggle but it's been demoted.
show_cities = true
// This cell places the rect backgrounds of the city lables. Since we call the
// svg:text.getBBox() method, this needs to run *after* the labels have been
// generated; thus, it's odd placement here.
outline_cities = {
let container = d3.select(map).select("#city_background_container");
if (show_cities) {
d3.select(map)
.selectAll("text")
.each(function (o) {
let bbox = this.getBBox();
container
.append("rect")
.attr("x", bbox.x - 2)
.attr("y", bbox.y - 2)
.attr("width", bbox.width + 4)
.attr("height", bbox.height + 4)
.attr("fill", "white")
.attr("fill-opacity", 0.4)
.attr("stroke", "black")
.attr("stroke-width", 0.4)
.style("pointer-events", "none");
});
} else {
container.selectAll("rect").remove();
}
}
state_dem_proportion = {
let dem_vote_total = d3.sum(
all_boundaries[0].boundaries.features.map((o) => o.properties.dem_vote)
);
let rep_vote_total = d3.sum(
all_boundaries[0].boundaries.features.map((o) => o.properties.rep_vote)
);
return dem_vote_total / (dem_vote_total + rep_vote_total);
}
function partisan_lean(district) {
let d = parseFloat(district.properties.dem_vote);
let r = parseFloat(district.properties.rep_vote);
let t = r + d;
return d / t;
}
function efficiency_gap(districts) {
let wasted_dem_votes = d3.sum(districts.map((d) => wasted_votes(d, "dem")));
let wasted_rep_votes = d3.sum(districts.map((d) => wasted_votes(d, "rep")));
let total_votes = d3.sum(
districts.map(
(d) =>
parseFloat(d.properties.dem_vote) + parseFloat(d.properties.rep_vote)
)
);
return (wasted_dem_votes - wasted_rep_votes) / total_votes;
}
function wasted_votes(district, p) {
let dvote = parseFloat(district.properties.dem_vote);
let rvote = parseFloat(district.properties.rep_vote);
let tvote = rvote + dvote;
if (p == "dem") {
if (dvote < tvote / 2) {
return dvote;
} else {
return dvote - tvote / 2;
}
} else {
if (rvote < tvote / 2) {
return rvote;
} else {
return rvote - tvote / 2;
}
}
}
path = d3.geoPath().projection(projection)
projection = d3.geoIdentity().reflectY(true).fitSize([w, h], congress_map_data)
h = 0.5 * w
w = width < 1200 ? width : 1200
congress_map_data = topojson.feature(map_data, map_data.objects.us_congress)
all_boundaries = Object.keys(map_data.objects).map((s) => ({
name: s,
boundaries: topojson.feature(map_data, map_data.objects[s])
}))
cities = all_boundaries[3].boundaries.features.map(function (o) {
let [x, y] = projection(o.geometry.coordinates);
let city = o.properties.city;
return { x, y, city };
})
map_data = FileAttachment("congressional_boundaries.json").json()
background = FileAttachment("im0.png").image()
import { Legend } from "@d3/color-legend"
tippy_style = html`<link style="display: none" rel="stylesheet" href="${await require.resolve(
`tippy.js/themes/light-border.css`
)}">`
tippy = require("tippy.js@6")
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.