[OSM-talk] Correcting coastlines

[Etienne]

See http://wiki.openstreetmap.org/index.php/Talk:Almien_coastlines_%28PGS%29for
a comparison and discussion of the PGS data around Sydney Opera House
with that of a GPS tracklog of the Opera House perimeter.

Etienne

On 8/23/06, J.D. Schmidt <jdsmobile at gmail.com> wrote:
>
> OJW skrev:
> > There was a discussion on IRC about whether to upload PGS coastline
> > data "as-is", or to try and correct the 10-30m shift that it appears to
> have
> > relative to some other datasets.
> >
> > http://wiki.openstreetmap.org/index.php/PGS_errata
> >
> > Any views on this?  Shifting the data will require us to justify how we
> > calculated the error (e.g. several of the screenshots people have given
> me
> > seem to be from google maps) and preferably we need a model for the
> error
> > which is consistant worldwide.
> >
> > Regards
> >
> > OJW
> >
> > p.s. how's Sydney harbour correlating with other data?
> >
> > p.p.s. did anyone email NGA to ask?
>
> The Digital Globe Sat imagery from Googlemaps on the screendumps I
> posted for Copenhagen, has only been used to visualize the shift to show
> it to others.. The actual shift was calculated from the municipality
> geodata available from the KMS portal.
>
> I downloaded the Sydney area, and made a gpx track from the coastline
> running from the Sydney Opera house and through three coves and inlets
> to the east, and plotted it on the Digital Globe imagery. Looks like
> it's shifted about 1 arcsecond north to the actual coastline. No E-W
> shift. But I have no actual geodata to verify the shift against, only
> the Digital Globe imagery from Googlemaps.
>
> J.D."Dutch" Schmidt
>
>
> _______________________________________________
> talk mailing list
> talk at openstreetmap.org
> http://lists.openstreetmap.org/cgi-bin/mailman/listinfo/talk
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.openstreetmap.org/pipermail/talk/attachments/20060823/e0713e1d/attachment.html>