import “../math/trigonometry”; import “geo”;
d3.geo.interpolate = function(source, target) {
return d3_geo_interpolate( source[0] * d3_radians, source[1] * d3_radians, target[0] * d3_radians, target[1] * d3_radians );
};
function d3_geo_interpolate(x0, y0, x1, y1) {
var cy0 = Math.cos(y0), sy0 = Math.sin(y0), cy1 = Math.cos(y1), sy1 = Math.sin(y1), kx0 = cy0 * Math.cos(x0), ky0 = cy0 * Math.sin(x0), kx1 = cy1 * Math.cos(x1), ky1 = cy1 * Math.sin(x1), d = 2 * Math.asin(Math.sqrt(d3_haversin(y1 - y0) + cy0 * cy1 * d3_haversin(x1 - x0))), k = 1 / Math.sin(d); var interpolate = d ? function(t) { var B = Math.sin(t *= d) * k, A = Math.sin(d - t) * k, x = A * kx0 + B * kx1, y = A * ky0 + B * ky1, z = A * sy0 + B * sy1; return [ Math.atan2(y, x) * d3_degrees, Math.atan2(z, Math.sqrt(x * x + y * y)) * d3_degrees ]; } : function() { return [x0 * d3_degrees, y0 * d3_degrees]; }; interpolate.distance = d; return interpolate;
};