The first and last points are the same so as to close the zone boundary.

Once the first point has been identified the remaining points are entered in clockwise order around the zone boundary.

In both cases the main single-digit roads normally define the zone boundaries.

Ticket price is higher for single rides that cross the zone boundary.

See this fare structure table for specific zone boundaries and definitions.

For the most part, zone boundaries followed galactic mean density.

Distortion of scale increases to 1.0010 at the zone boundaries along the equator.

Under the best of circumstances this would be slow and tedious exercise, but the latest surveys reported movement in the zone boundaries.

However, as land use patterns change over time, zone boundaries will need changing, adding to the procedural complexity.

Common ways include varying the tone of the background color, or by running a weak line along the zone boundaries.