I wonder how well Google Earth matches up with this in terms of precision? Has anybody ever checked?
Best, Jim Tallman www.spectrasundial.com www.artisanindustrials.com jtall...@artisanindustrials.com 513-253-5497 On Apr 30, 2014 1:57 PM, rmallett <postmas...@rmallett.plus.com> wrote: > > On 30/04/2014 17:37, Douglas Bateman wrote: >> >> This is a new club consisting, so far, of two members: Frank King and myself. >> >> >> >> After the successful British Sundial Society conference, the Sunday morning >> was allocated to tours of the Greenwich Observatory. Quite independently, >> Frank and I had the intention of location the WGS84 meridian, some 90m east >> of the Greenwich brass strip. Frank had an eTrex tracker and an app on his >> mobile phone, and I had an Axxera GPS tracker linked to my iPad. >> >> >> >> The images, if the system will let them through, show 0º 0' 0". Anyone else >> willing to join this new exclusive club? Plenty of places to straddle the >> line between the north pole and the south pole. >> >> >> >> Doug (and Frank) >> >> >> >> >> >> >> >> >> >> --------------------------------------------------- >> >> https://lists.uni-koeln.de/mailman/listinfo/sundial >> >> >> > > I would be all in favour of marking the zero meridian for the whole of its > length on land, if that's the intention. Why is the difference 90 metres ? > Wikipedia says 200 metres ("102.5 metres east of its last position") at > http://en.wikipedia.org/wiki/Meridian_%28geography%29 - see also > http://en.wikipedia.org/wiki/Prime_meridian > > http://wikimapia.org/3323604/Meridian-Building says :- > > "Curiously, whether by accident or design, the location of the WGS84 0° > meridian is marked in Greenwich by the presence of a waste basket on the path > leading more or less due east from the observatory containing the transit > telescope." > > > Is it the old thing about GPS receivers being deliberately inaccurate to > preserve military secrets, or is it that dedicated GPS receivers are more > accurate than smart phones and tablets ? I know that Harriet James used a > hand held GPS receiver when measuring the location of my house. > > > -- > > -- > > Richard Mallett > > Eaton Bray, Dunstable > > South Beds. UK --------------------------------------------------- https://lists.uni-koeln.de/mailman/listinfo/sundial
