code: def get_transform(bounds, size=4096):
      
      tx, ty = bounds[0], bounds[1]
      sx, sy = (bounds[2] - bounds[0]) / size, (bounds[3] - bounds[1]) / size
  
      def forward(lon, lat):
          """ Transform a longitude and latitude to TopoJSON integer space.
          """
          return int(round((lon - tx) / sx)), int(round((lat - ty) / sy))
  
      return dict(translate=(tx, ty), scale=(sx, sy)), forward
docs: Return a TopoJSON transform dictionary and a point-transforming function.
  
          Size is the tile size in pixels and sets the implicit output
          resolution.