[OSM-talk] Removing ways in Potlatch
Chris Hill
osm at raggedred.net
Mon Jun 21 12:03:22 BST 2010
Eugene Alvin Villar wrote:
> One big problem with any 4th dimensional idea is plate tectonics. I'm
> willing to bet that if you were to map how London was before the great
> fire of 1666, the coordinates of places won't match their current
> locations in WGS84 coordinates.
And exactly how do you propose that we get accurate coordinates for the
positions of streets in 1665 other using a modern surveyed overlay? I
don't think Samuel Pepys supplemented his diary with GPS derived WGS84
coordinates. :-)
Any surveying that was done then (some rather accurately) would be done
with reference to a fixed object on the landmass. These would have moved
coherently on a tectonic plate. The 4 metres or so the plate bearing
London has moved since the mid 17thC is only just within our current
consumer GPS resolution and therefore on the boundary of our error
range. Besides, all this plate movement is relative, who says London has
moved at all?
--
Cheers, Chris
user: chillly
More information about the talk
mailing list