def get_point(track, time_idx):
    """
    Get GPX track point from a track for a given time index.
    :param track: track DataFrame
    :param time_idx: time index
    :return: GPX track point for time index, or None if no point exists at
    that time
    """
    try:
        return track.loc[time_idx]
    except KeyError:
        return None