viewof height = Inputs.range([0, 800], {label: "Height", step: 1, value:500})
map = {
const svg = d3.create("svg").attr("width", width).attr("height", height);
const viz = svg.append("g");
//.attr("transform", "rotate(90) translate(0 -" + width + ")");
const path = d3.geoPath(clipped);
const outlinePath = viz
.append("path")
.datum(outline)
.attr("id", "outline")
.attr("stroke", "#aaa")
.attr("opacity", 1)
.attr("stroke-width", 1)
.attr("stroke-linejoin", "round")
.attr("fill", "#eee")
.attr("d", path)
.attr("pointer-events", "none");
const landPath = viz
.append("g")
.attr("id", "land")
.selectAll("path")
.data(ne_110m_land.features)
.join("path")
.attr("id", (d) => d.properties.formal_en)
.attr("d", path)
.attr("fill", "#fff")
.attr("fill-opacity", 1)
.attr("stroke", "#043B62")
.attr("stroke-alignment", "inner");
const poli = viz
.append("g")
.attr("id", "land")
.selectAll("path")
.data(unrotatedPolygons.features.filter((d, i) => i === selectedId))
.join("path")
.attr("d", path)
.attr("fill", "none")
.attr("fill-opacity", 1)
.attr("stroke", "red")
.attr("stroke-alignment", "inner");
const projCentroids = unrotatedPolygons.features.map((d) =>
projection(d3.geoCentroid(d))
);
// 1. Get the selected face polygon and find its centroid
const face = unrotatedPolygons.features[selectedId];
const centroid = d3.geoCentroid(face); // [longitude, latitude]
// 2. Define a point slightly north of the centroid (e.g., 10° north)
const northRef = [centroid[0], centroid[1] + 10];
// 3. Project both points
const [cx, cy] = clipped(centroid);
const [nx, ny] = clipped(northRef);
const cent = viz
.append("g")
.append("circle")
.attr("cx", cx)
.attr("cy", cy)
.attr("r", 5)
.attr("fill", "blue")
.attr("stroke", "none");
viz
.append("line")
.attr("x1", cx)
.attr("y1", cy)
.attr("x2", nx)
.attr("y2", ny)
.attr("stroke", "black")
.attr("stroke-width", 2);
return svg.node();
}
d3 = require("d3@7.9", "d3-geo@3.1.1", "d3-geo-polygon@2.0.1")
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.
