Published
Edited
Sep 25, 2021
Insert cell
Insert cell
Insert cell
Insert cell
Insert cell
Insert cell
Insert cell
Insert cell
Insert cell
{
const svg = d3
.create("svg")
.attr("viewBox", [0, 0, width, height])
.style("width", "100%")
.style("height", "auto");

const path = d3.geoPath(); // i.e. projection == null

// Ocean
svg
.append("rect")
.attr("width", width)
.attr("height", height)
.attr("fill", colors.ocean);

// A group for land and borders
const g = svg.append("g").attr("transform", `translate(${translateX}, 0)`);

// Land & country border
g.append("path")
.attr("fill", colors.land)
.attr("stroke", colors.country)
.attr("stroke-width", 0.5)
.attr("d", path(topojson.feature(japan, "country"))); // same as `japan.objects.country`

// Prefectural borders
const prefecturalBorders = topojson.mesh(
japan,
japan.objects.prefectures,
(a, b) => a !== b
);
g.append("path")
.datum(prefecturalBorders)
.attr("fill", "none")
.attr("stroke", colors.prefecture)
.attr("stroke-width", 1.2)
.attr("d", path);

// Municipal borders
const municipalBorders = topojson.mesh(
japan,
japan.objects.municipalities,
(a, b) => {
return a !== b && ((a.id / 1000) | 0) === ((b.id / 1000) | 0);
}
);
g.append("path")
.datum(municipalBorders)
.attr("fill", "none")
.attr("stroke", colors.municipality)
.attr("stroke-width", 0.5)
.attr("d", path);

return svg.node();
}
Insert cell
Insert cell
{
const context = DOM.context2d(width, height);

const path = d3.geoPath(null, context); // set context here

// Ocean
context.beginPath();
context.fillStyle = colors.ocean;
context.fillRect(0, 0, width, height);

context.translate(translateX, 0);

// Land
context.beginPath();
path(topojson.mesh(japan, japan.objects.country));
context.fillStyle = colors.land;
context.fill();
context.closePath();

// Country border
context.beginPath();
path(topojson.mesh(japan, japan.objects.country));
context.strokeStyle = colors.country;
context.lineWidth = 0.5;
context.stroke();
context.closePath();

// Prefecture borders
context.beginPath();
path(topojson.mesh(japan, japan.objects.prefectures, (a, b) => a !== b));
context.strokeStyle = colors.prefecture;
context.lineWidth = 1.2;
context.stroke();
context.closePath();

// Municipality borders
context.beginPath();
path(
topojson.mesh(japan, japan.objects.municipalities, (a, b) => {
return a !== b && ((a.id / 1000) | 0) === ((b.id / 1000) | 0);
})
);
context.strokeStyle = colors.municipality;
context.lineWidth = 0.5;
context.stroke();
context.closePath();

return context.canvas;
}
Insert cell

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.
Learn more