<P> Ideal time zones , such as nautical time zones , are based on the mean solar time of a particular meridian located in the middle of that zone with boundaries located 7.5 degrees east and west of the meridian . In practice , zone boundaries are often drawn much farther to the west with often irregular boundaries , and some locations base their time on meridians located far to the east . </P>
<P> Ideal time zones , such as nautical time zones , are based on the mean solar time of a particular meridian located in the middle of that zone with boundaries located 7.5 degrees east and west of the meridian . In practice , zone boundaries are often drawn much farther to the west with often irregular boundaries , and some locations base their time on meridians located far to the east . </P>
what is the line in the middle of a time zone that in theory determines the time of that zone
what is the line in the middle of a time zone that in theory determines the time of that zone
mean solar time
mean solar time