import “../core/noop”; import “../math/trigonometry”; import “geo”; import “stream”;
d3.geo.centroid = function(object) {
d3_geo_centroidW0 = d3_geo_centroidW1 = d3_geo_centroidX0 = d3_geo_centroidY0 = d3_geo_centroidZ0 = d3_geo_centroidX1 = d3_geo_centroidY1 = d3_geo_centroidZ1 = d3_geo_centroidX2 = d3_geo_centroidY2 = d3_geo_centroidZ2 = 0; d3.geo.stream(object, d3_geo_centroid); var x = d3_geo_centroidX2, y = d3_geo_centroidY2, z = d3_geo_centroidZ2, m = x * x + y * y + z * z; // If the area-weighted centroid is undefined, fall back to length-weighted centroid. if (m < ε2) { x = d3_geo_centroidX1, y = d3_geo_centroidY1, z = d3_geo_centroidZ1; // If the feature has zero length, fall back to arithmetic mean of point vectors. if (d3_geo_centroidW1 < ε) x = d3_geo_centroidX0, y = d3_geo_centroidY0, z = d3_geo_centroidZ0; m = x * x + y * y + z * z; // If the feature still has an undefined centroid, then return. if (m < ε2) return [NaN, NaN]; } return [Math.atan2(y, x) * d3_degrees, d3_asin(z / Math.sqrt(m)) * d3_degrees];
};
var d3_geo_centroidW0,
d3_geo_centroidW1, d3_geo_centroidX0, d3_geo_centroidY0, d3_geo_centroidZ0, d3_geo_centroidX1, d3_geo_centroidY1, d3_geo_centroidZ1, d3_geo_centroidX2, d3_geo_centroidY2, d3_geo_centroidZ2;
var d3_geo_centroid = {
sphere: d3_noop, point: d3_geo_centroidPoint, lineStart: d3_geo_centroidLineStart, lineEnd: d3_geo_centroidLineEnd, polygonStart: function() { d3_geo_centroid.lineStart = d3_geo_centroidRingStart; }, polygonEnd: function() { d3_geo_centroid.lineStart = d3_geo_centroidLineStart; }
};
// Arithmetic mean of Cartesian vectors. function d3_geo_centroidPoint(λ, φ) {
λ *= d3_radians; var cosφ = Math.cos(φ *= d3_radians); d3_geo_centroidPointXYZ(cosφ * Math.cos(λ), cosφ * Math.sin(λ), Math.sin(φ));
}
function d3_geo_centroidPointXYZ(x, y, z) {
++d3_geo_centroidW0; d3_geo_centroidX0 += (x - d3_geo_centroidX0) / d3_geo_centroidW0; d3_geo_centroidY0 += (y - d3_geo_centroidY0) / d3_geo_centroidW0; d3_geo_centroidZ0 += (z - d3_geo_centroidZ0) / d3_geo_centroidW0;
}
function d3_geo_centroidLineStart() {
var x0, y0, z0; // previous point d3_geo_centroid.point = function(λ, φ) { λ *= d3_radians; var cosφ = Math.cos(φ *= d3_radians); x0 = cosφ * Math.cos(λ); y0 = cosφ * Math.sin(λ); z0 = Math.sin(φ); d3_geo_centroid.point = nextPoint; d3_geo_centroidPointXYZ(x0, y0, z0); }; function nextPoint(λ, φ) { λ *= d3_radians; var cosφ = Math.cos(φ *= d3_radians), x = cosφ * Math.cos(λ), y = cosφ * Math.sin(λ), z = Math.sin(φ), w = Math.atan2( Math.sqrt((w = y0 * z - z0 * y) * w + (w = z0 * x - x0 * z) * w + (w = x0 * y - y0 * x) * w), x0 * x + y0 * y + z0 * z); d3_geo_centroidW1 += w; d3_geo_centroidX1 += w * (x0 + (x0 = x)); d3_geo_centroidY1 += w * (y0 + (y0 = y)); d3_geo_centroidZ1 += w * (z0 + (z0 = z)); d3_geo_centroidPointXYZ(x0, y0, z0); }
}
function d3_geo_centroidLineEnd() {
d3_geo_centroid.point = d3_geo_centroidPoint;
}
// See J. E. Brock, The Inertia Tensor for a Spherical Triangle, // J. Applied Mechanics 42, 239 (1975). function d3_geo_centroidRingStart() {
var λ00, φ00, // first point x0, y0, z0; // previous point d3_geo_centroid.point = function(λ, φ) { λ00 = λ, φ00 = φ; d3_geo_centroid.point = nextPoint; λ *= d3_radians; var cosφ = Math.cos(φ *= d3_radians); x0 = cosφ * Math.cos(λ); y0 = cosφ * Math.sin(λ); z0 = Math.sin(φ); d3_geo_centroidPointXYZ(x0, y0, z0); }; d3_geo_centroid.lineEnd = function() { nextPoint(λ00, φ00); d3_geo_centroid.lineEnd = d3_geo_centroidLineEnd; d3_geo_centroid.point = d3_geo_centroidPoint; }; function nextPoint(λ, φ) { λ *= d3_radians; var cosφ = Math.cos(φ *= d3_radians), x = cosφ * Math.cos(λ), y = cosφ * Math.sin(λ), z = Math.sin(φ), cx = y0 * z - z0 * y, cy = z0 * x - x0 * z, cz = x0 * y - y0 * x, m = Math.sqrt(cx * cx + cy * cy + cz * cz), u = x0 * x + y0 * y + z0 * z, v = m && -d3_acos(u) / m, // area weight w = Math.atan2(m, u); // line weight d3_geo_centroidX2 += v * cx; d3_geo_centroidY2 += v * cy; d3_geo_centroidZ2 += v * cz; d3_geo_centroidW1 += w; d3_geo_centroidX1 += w * (x0 + (x0 = x)); d3_geo_centroidY1 += w * (y0 + (y0 = y)); d3_geo_centroidZ1 += w * (z0 + (z0 = z)); d3_geo_centroidPointXYZ(x0, y0, z0); }
}