The short answer is that any coordinate specification has to be given in reference to a particular datum. Here's the Wikipedia article on datums: http://en.wikipedia.org/wiki/Datum_%28geodesy%29
> > Bravo, Tony Finch, for sharing this. I had no idea location was so > complex! > > Thank you. > > Mac > > > > > >>On 13 Mar 2011, at 13:44, "J. Tallman" >><<mailto:jtall...@artisanindustrials.com>jtall...@artisanindustrials.com> >>wrote: >> >>> >>>I just saw on the news that the recent quake in Japan shifted the >>>earth's axis by 4 inches and that the main island of Japan moved >>>nearly 8 feet. >>> >>>Could someone on the list put this into perspective? As an example, >>>I would imagine that the legal descriptions for property lines >>>based on precise lat/long coordinates now need to be revised - here >>>in SW Ohio the plats in the county offices are all described this >>>way. >>> >> >>The best description I have seen of how terrestrial location systems >>work is this booklet published by the British Ordnance Survey. It >>has a lot more detail about Britain than anywhere else but a lot of >>the techniques and technologies are universal. >> >> >><http://dotat.at/:/PM89C>http://dotat.at/:/PM89C >> >>Tony. >>-- >>f.anthony.n.finch <d...@dotat.at> http://dotat.at/ >> >>--------------------------------------------------- >>https://lists.uni-koeln.de/mailman/listinfo/sundial > > --------------------------------------------------- > https://lists.uni-koeln.de/mailman/listinfo/sundial > > --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
