code: def set_neighbor_data(self, elev_fn, dem_proc, interp=None):
          
          if interp is None:
              interp = self.build_interpolator(dem_proc)
          opp = {'top': 'bottom', 'left': 'right'}
          for key in self.neighbors[elev_fn].keys():
              tile = self.neighbors[elev_fn][key]
              if tile == '':
                  continue
              oppkey = key
              for me, neigh in opp.iteritems():
                  if me in key:
                      oppkey = oppkey.replace(me, neigh)
                  else:
                      oppkey = oppkey.replace(neigh, me)
              opp_edge = self.neighbors[tile][oppkey]
              if opp_edge == '':
                  continue
  
              interp.values = dem_proc.uca[::-1, :]
  #            interp.values[:, 0] = np.ravel(dem_proc.uca)  # for other interp.
              # for the top-left tile we have to set the bottom and right edges
              # of that tile, so two edges for those tiles
              for key_ed in oppkey.split('-'):
                  self.edges[tile][key_ed].set_data('data', interp)
  
              interp.values = dem_proc.edge_done[::-1, :].astype(float)
  #            interp.values[:, 0] = np.ravel(dem_proc.edge_done)
              for key_ed in oppkey.split('-'):
                  self.edges[tile][key_ed].set_data('done', interp)
docs: From the elevation filename, we can figure out and load the data and
          done arrays.