Plot.plot({
projection: {
type: "equal-earth",
rotate: [90, 0]
},
color: {
legend: true,
label: "Distance from Tonga (km)",
transform: (d) => 111.2 * d,
zero: true
},
marks: [
Plot.geo(land),
Plot.geo([0.5, 179.5].concat(d3.range(10, 171, 10)), {
geometry: d3.geoCircle().center([-175.38, -20.57]).radius((r) => r),
stroke: (r) => r,
strokeWidth: 2
}),
Plot.sphere()
]
})