2010/5/15 Iván Sánchez Ortega <i...@sanchezortega.es>: > Problem is, the center of mass moves along with the continental drift. Have > you heard of gravimetrics? You can have looooots of fun with it.
Yes I know, but I was outlining the basic reason why most co-ords on most plates shifted 50-200m (or more) when governments started shifting to mass centric models. Also, even though most countries shifted to mass centric based systems, they still using plate fixed models that drift from the GPS system, in the case of DGA94, by about 7cm NNE on average per year, but the plate isn't moving that much, since GPS uses the equator and the 0 degree longitude as fixed reference points which also move, although different parts of different plates move at different speeds and in different directions. So as you said lots of fun to be had by all if you want to get into it :) _______________________________________________ talk mailing list talk@openstreetmap.org http://lists.openstreetmap.org/listinfo/talk
