gistfile1.txt

CGFloat maxX = 0.0f;
CGFloat maxY = 0.0f;

[self.points enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop){
   CGPoint point = [obj CGPointValue];
   if(point.x > maxX){
       maxX = point.x;
   }

   if(point.y > maxY){
      maxY = point.y;
   }
}];