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Contents
// @import parallel2
function conicConformal(φ0, φ1) {
var cosφ0 = Math.cos(φ0),
t = function(φ) { return Math.tan(π / 4 + φ / 2); },
n = Math.log(cosφ0 / Math.cos(φ1)) / Math.log(t(φ1) / t(φ0)),
F = cosφ0 * Math.pow(t(φ0), n) / n;
function forward(λ, φ) {
var ρ = Math.abs(Math.abs(φ) - π / 2) < ε ? 0 : F / Math.pow(t(φ), n);
return [
ρ * Math.sin(n * λ),
F - ρ * Math.cos(n * λ)
];
}
forward.invert = function(x, y) {
var ρ0_y = F - y,
ρ = sgn(n) * Math.sqrt(x * x + ρ0_y * ρ0_y);
return [
Math.atan2(x, ρ0_y) / n,
2 * Math.atan(Math.pow(F / ρ, 1 / n)) - π / 2
];
};
return forward;
}
(d3.geo.conicConformal = function() { return parallel2Projection(conicConformal); }).raw = conicConformal;
Version data entries
2 entries across 2 versions & 1 rubygems