Sha256: fb4bd780d5a1d2ddbd3306ec239fdffce628cbe7f6920d4de1a7488992bbc02e
Contents?: true
Size: 823 Bytes
Versions: 4
Compression:
Stored size: 823 Bytes
Contents
function mtFlatPolarQuartic(λ, φ) {
var k = (1 + Math.SQRT1_2) * Math.sin(φ),
θ = φ;
for (var i = 0, δ; i < 25; i++) {
θ -= δ = (Math.sin(θ / 2) + Math.sin(θ) - k) / (.5 * Math.cos(θ / 2) + Math.cos(θ));
if (Math.abs(δ) < ε) break;
}
return [
λ * (1 + 2 * Math.cos(θ) / Math.cos(θ / 2)) / (3 * Math.SQRT2),
2 * Math.sqrt(3) * Math.sin(θ / 2) / Math.sqrt(2 + Math.SQRT2)
];
}
mtFlatPolarQuartic.invert = function(x, y) {
var sinθ_2 = y * Math.sqrt(2 + Math.SQRT2) / (2 * Math.sqrt(3)),
θ = 2 * asin(sinθ_2);
return [
3 * Math.SQRT2 * x / (1 + 2 * Math.cos(θ) / Math.cos(θ / 2)),
asin((sinθ_2 + Math.sin(θ)) / (1 + Math.SQRT1_2))
];
};
(d3.geo.mtFlatPolarQuartic = function() { return projection(mtFlatPolarQuartic); }).raw = mtFlatPolarQuartic;
Version data entries
4 entries across 4 versions & 1 rubygems