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change getCentroid

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sdikiy
2012-03-30 23:20:21 +03:00
parent 23301e10ea
commit 0460bd2ae8
1 changed files with 19 additions and 16 deletions
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35
lib/OpenLayers/Geometry/LinearRing.js
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@@ -198,23 +198,26 @@ OpenLayers.Geometry.LinearRing = OpenLayers.Class(
} else if (len > 2) {
var sumX = 0.0;
var sumY = 0.0;
var averX = 0.0;
var averY = 0.0;
for (var i = 0; i < len; i++) {
averX += this.components[i].x;
averY += this.components[i].y;
}
averX = averX / len;
averY = averY / len;
for (var i = 0; i < len - 1; i++) {
var b = this.components[i];
var c = this.components[i+1];
sumX += (b.x + c.x - 2 * averX) * ((b.x - averX) * (c.y - averY) - (c.x - averX) * (b.y - averY));
sumY += (b.y + c.y - 2 * averY) * ((b.x - averX) * (c.y - averY) - (c.x - averX) * (b.y - averY));
}
var x0 = this.components[0].x;
var y0 = this.components[0].y;
var area = -1 * this.getArea();
var x = averX + sumX / (6 * area);
var y = averY + sumY / (6 * area);
if (area != 0) {
for (var i = 0; i < len - 1; i++) {
var b = this.components[i];
var c = this.components[i+1];
sumX += (b.x + c.x - 2 * x0) * ((b.x - x0) * (c.y - y0) - (c.x - x0) * (b.y - y0));
sumY += (b.y + c.y - 2 * y0) * ((b.x - x0) * (c.y - y0) - (c.x - x0) * (b.y - y0));
}
var x = x0 + sumX / (6 * area);
var y = y0 + sumY / (6 * area);
} else {
for (var i = 0; i < len - 1; i++) {
sumX += this.components[i].x;
sumY += this.components[i].y;
}
var x = sumX / (len - 1);
var y = sumY / (len - 1);
}
return new OpenLayers.Geometry.Point(x, y);
} else {
return null;