def path_trace(map_projection, pts, closed=False, meta_data=None):
return PathTrace(map_projection, pts, closed=closed, meta_data=meta_data)<EOL>
path_trace(proj, points) yields a path-trace object that represents the given path of points on
  the given map projection proj.

The following options may be given:
  * closed (default: False) specifies whether the points form a closed loop. If they do form
    such a loop, the points should be given in the same ordering (counter-clockwise or
    clockwise) that mesh vertices are given in; usually counter-clockwise.
  * meta_data (default: None) specifies an optional additional meta-data map to append to the
    object.