[OSM-talk] What does WGS84 mean for openstreetmap these days?

Yantisa Akhadi yantisa at gmail.com
Fri Dec 20 01:56:44 UTC 2019


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 <gdt at lexort.com> wrote:

> "Jóhannes Birgir Jensson" <joi at 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 at openstreetmap.org
> https://lists.openstreetmap.org/listinfo/talk
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk/attachments/20191220/c8a6e44f/attachment-0001.html>


More information about the talk mailing list