Springfield
Silver Member
Ellie Baba said:.....What that value of a given longitude is depends of course on where we begin to count--on where zero longitude is. For historical reasons, the meridian passing the old Royal Astronomical Observatory in Greenwich, England, is the one chosen as zero longitude.
Except in this case; the stone maps require that zero longitude is the meridian passing through Washington, D.C., USA. .....
Things get really interesting when you use the longitudinal prime meridian than passes through Paris, France.