Yes, WGS84 because that’s what’s used by GPS (which was, after all, the original data source for OSM).
Of course, then there’s the question of *which* WGS84 definition we’re talking about. You actually can’t assumed that current definitions of WGS84 and NAD83 are <1m difference. You can dip your toe into the complexity here: http://www.ngs.noaa.gov/CORS/Articles/WGS84NAD83.pdf Also note, that the satellite photography used for a great deal of OSM mapping has much less than 1m accuracy, and as you note, unless you’re using expensive GPS, you’re not likely to get <1m accuracy anyway. Relatedly, I’m curious if anyone has used one of these guys: http://gps.dualav.com/explore-by-lifestyle/outdoors/ d. On Dec 31, 2014, at 13:56, Dave Mansfield <[email protected]> wrote: > > That brings up a good question. What datum is used by OSM? I would assume > it's WGS 84. NAD 83 is within about a meter of WGS 84. That’s closer than the > GPS units most of us have so would not cause much of an error if any. NAD 27 > on the other hand could be off by as much as 180 meters. > > Dave > > -----Original Message----- > From: stevea [mailto:[email protected]] > Sent: Wednesday, December 31, 2014 2:24 PM > To: [email protected] > Cc: [email protected] > Subject: Re: [Talk-us] Rail westerly > > I examine these in JOSM right now. First they need to be unzipped, and it > looks like the (provided on that web page) PRJ file to change from WGS 84 > (default) to either NAD 27 or 83 projection is required. > I haven't done that to these data in the instant case, but I've fiddled these > before and I think it is doable. > > SteveA > California > > _______________________________________________ > Talk-us mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/talk-us > > > _______________________________________________ > Talk-us mailing list > [email protected] > https://lists.openstreetmap.org/listinfo/talk-us _______________________________________________ Imports-us mailing list [email protected] https://lists.openstreetmap.org/listinfo/imports-us
