public Object parseXMLObject(XMLObject xo) throws XMLParseException {
LinkedList<Point2D> Point2Ds = new LinkedList<Point2D>();
boolean closed;
Polygon2D polygon;
if (xo.getChild(Polygon2D.class) != null) { // This is a regular polygon
polygon = (Polygon2D) xo.getChild(Polygon2D.class);
} else { // This is an arbitrary polygon
KMLCoordinates coordinates = (KMLCoordinates) xo.getChild(KMLCoordinates.class);
closed = xo.getAttribute(CLOSED, false);
if ((!closed && coordinates.length < 3) || (closed && coordinates.length < 4))
throw new XMLParseException(
"Insufficient point2Ds in polygon '"
+ xo.getId()
+ "' to define a polygon in 2D");
for (int i = 0; i < coordinates.length; i++)
Point2Ds.add(new Point2D.Double(coordinates.x[i], coordinates.y[i]));
polygon = new Polygon2D(Point2Ds, closed);
}
polygon.setFillValue(xo.getAttribute(FILL_VALUE, 0.0));
return polygon;
}
private static LinkedList<Point2D> getCirclePoints(
double centerLat, double centerLong, int numberOfPoints, double radius) {
LinkedList<Point2D> Point2Ds = new LinkedList<Point2D>();
double lat1, long1;
double d_rad;
double delta_pts;
double radial, lat_rad, dlon_rad, lon_rad;
// convert coordinates to radians
lat1 = Math.toRadians(centerLat);
long1 = Math.toRadians(centerLong);
// radius is in meters
d_rad = radius / 6378137;
// loop through the array and write points
for (int i = 0; i <= numberOfPoints; i++) {
delta_pts = 360 / (double) numberOfPoints;
radial = Math.toRadians((double) i * delta_pts);
// This algorithm is limited to distances such that dlon < pi/2
lat_rad =
Math.asin(
Math.sin(lat1) * Math.cos(d_rad)
+ Math.cos(lat1) * Math.sin(d_rad) * Math.cos(radial));
dlon_rad =
Math.atan2(
Math.sin(radial) * Math.sin(d_rad) * Math.cos(lat1),
Math.cos(d_rad) - Math.sin(lat1) * Math.sin(lat_rad));
lon_rad = ((long1 + dlon_rad + Math.PI) % (2 * Math.PI)) - Math.PI;
Point2Ds.add(new Point2D.Double(Math.toDegrees(lat_rad), Math.toDegrees(lon_rad)));
}
return Point2Ds;
}
public Polygon2D clip(Rectangle2D boundingBox) {
LinkedList<Point2D> clippedPolygon = new LinkedList<Point2D>();
Point2D p; // current Point2D
Point2D p2; // next Point2D
// make copy of original polygon to work with
LinkedList<Point2D> workPoly = new LinkedList<Point2D>(point2Ds);
// loop through all for clipping edges
for (Side side : Side.values()) {
clippedPolygon.clear();
for (int i = 0; i < workPoly.size() - 1; i++) {
p = workPoly.get(i);
p2 = workPoly.get(i + 1);
if (isInsideClip(p, side, boundingBox)) {
if (isInsideClip(p2, side, boundingBox))
// here both point2Ds are inside the clipping window so add the second one
clippedPolygon.add(p2);
else
// the seond Point2D is outside so add the intersection Point2D
clippedPolygon.add(intersectionPoint2D(side, p, p2, boundingBox));
} else {
// so first Point2D is outside the window here
if (isInsideClip(p2, side, boundingBox)) {
// the following Point2D is inside so add the insection Point2D and also p2
clippedPolygon.add(intersectionPoint2D(side, p, p2, boundingBox));
clippedPolygon.add(p2);
}
}
}
// make sure that first and last element are the same, we want a closed polygon
if (!clippedPolygon.getFirst().equals(clippedPolygon.getLast()))
clippedPolygon.add(clippedPolygon.getFirst());
// we have to keep on working with our new clipped polygon
workPoly = new LinkedList<Point2D>(clippedPolygon);
}
return new Polygon2D(clippedPolygon, true);
}
