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18 lines
508 B
18 lines
508 B
import {geoProjection as projection} from "d3-geo";
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import {asin, cos, sin, sqrt, sqrtPi} from "./math.js";
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var sqrt3 = sqrt(3);
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export function crasterRaw(lambda, phi) {
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return [sqrt3 * lambda * (2 * cos(2 * phi / 3) - 1) / sqrtPi, sqrt3 * sqrtPi * sin(phi / 3)];
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}
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crasterRaw.invert = function(x, y) {
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var phi = 3 * asin(y / (sqrt3 * sqrtPi));
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return [sqrtPi * x / (sqrt3 * (2 * cos(2 * phi / 3) - 1)), phi];
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};
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export default function() {
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return projection(crasterRaw)
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.scale(156.19);
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}
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