title: Boost.Geometry polygon point assignment
body: <p>i am trying to use boost geometry and having trouble assigning points to a polygon.
  Lets assume i create an static vector of points</p>
  
  <pre><code>boost::geometry::model::d2::point_xy&lt;double&gt; &gt;* a; 
  </code></pre>
  
  <p>And then i create a polygon: </p>
  
  <pre><code>boost::geometry::model::polygon&lt;boost::geometry::model::d2::point_xy&lt;double&gt; &gt; polygon;
  </code></pre>
  
  <p>Assuming i have already defined the values of the points of a.</p>
  
  <p>How can i assign the points from a to P?</p>