To add more challenges to this issue is imagery offset <https://wiki.openstreetmap.org/wiki/Imagery_Offset_Database>. The value can even be varied from tiles to tiles, that we often need to shift the object a couple of meters away. In a remote area, where there are no GPS traces as a reference, satellite imagery is often the only reference even when possibly it was a couple of meters off.
Best, Iyan On Fri, Dec 20, 2019 at 12:59 AM Greg Troxel <g...@lexort.com> wrote: > "Jóhannes Birgir Jensson" <j...@betra.is> writes: > > > I don't think we can or will be providing accuracy up to cm when most > > of the stuff we map from our chairs is off by a meter or two anyways - > > the beauty is that it doesn't matter for 99,99% of users. If a > > centimeter matters then we are probably dealing with legal matters and > > there OSM makes it quite clear it is not suitable for such. > > My actual proposal, as opposed to the things I pointed out I wasn't > proposing, is about removing the ~2m uncertainty that exists from our > current definition. > > As for cm level, OSM does not have accuracy specifications and won't. > Some people like to be accurate, and others like to add lots of detailed > tags. Between us we have great map. I don't agree that anybody who is > trying to be more accurate is necessarily concerned with something that > is "legal". I would expect many people would like to see better than 2m > accuracy. > > Certainly cm-level is very difficult, and I see that as being pretty far > out in the future. > > You didn't comment on the notion of defuzzing the reference to WGS84, so > I'll assume you are ok with that. > > > Also regarding the accuracy, as another fast moving country Iceland is > > actually splitting in the middle and so it edges west and east and > > south as well, depending on where you are in the country. We've had 3 > > official national datums now, ISN93, ISN2004 and ISN2016 (helpfully > > naming them after years). The fact is that pretty much everything is > > still running in ISN93, ISN2004 saw very little uptake and ISN2016 has > > started very slowly. > > > > So for Iceland we do know that we are never going to achieve a > > centimeter accuracy, pretty much ever, and don't expect a free people > > sourced geographical database to reach it. > > Interesting about the datum history. But this is the cm strawman I > wasn't talking about, not the 2m issue. > > I would not be surprised if in 20 years OSM had some approach to > coordinates of crust-fixed points. > > _______________________________________________ > talk mailing list > talk@openstreetmap.org > https://lists.openstreetmap.org/listinfo/talk >
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