code: public void mergeNE(double x, double y) {
  		if (xmin > x)
  			xmin = x;
  		else if (xmax < x)
  			xmax = x;
  
  		if (ymin > y)
  			ymin = y;
  		else if (ymax < y)
  			ymax = y;
  	}
docs: Merges a point with this envelope without checking if the envelope is
  empty. Use with care.
  @param x The x coord of the point
  @param y the y coord in the point