out.writeStartElement("bucket");
writeElement("bucketindex", bucketIndex.toString());
writeElement("bucketid", bucket.id().toString());
Envelope env = new Envelope();
env.setToNull();
bucket.expand(env);
out.writeStartElement("bbox");
writeElement("minx", Double.toString(env.getMinX()));
writeElement("maxx", Double.toString(env.getMaxX()));
writeElement("miny", Double.toString(env.getMinY()));
writeElement("maxy", Double.toString(env.getMaxY()));