title: Discrete Convex Hull
body: <p>In python, given m random points in an n x n grid, how do I calculate a (roughly) convex hull where the hull can only be created using the points on the discrete grid rather than a continuous point? </p>
  
  <p>modules like scipy.spatial only give continuous convex hulls, where the lines connecting vertices are purely algebraic, but I want approximately a convex hull where the boundary is discrete. </p>