[x3d-public] GeoPositionInterpolator revision for V4.0

[Andreas Plesch]

Thanks, Doug and Mike.

I may add that it looks like that cobweb will offer great circle
interpolation (among other geospatial capabilities) in a future release.


Date: Thu, 28 Apr 2016 07:59:54 -0700
> From: Mike McCann <mccann at mbari.org>
>
> This seems like a good alternative. Let me propose a prose change for
> http://www.web3d.org/documents/specifications/19775-1/V3.3/Part01/components/geodata.html#GeoPositionInterpolator
> :
>
> The GeoPositionInterpolator node provides an interpolator capability where
> key values are specified in geographic coordinates and the interpolation is
> performed within the specified spatial reference frame.
>
> becomes:
>
> The GeoPositionInterpolator node provides an interpolator capability where
> key values are specified in geographic coordinates and the interpolation is
> performed within the specified spatial reference frame. Great circle
> interpolation is recommended, future specifications will require great
> circle interpolation.
>
>
Thanks, good prose. It may be help to explain a bit what great circle
interpolation is about. Something like:

Interpolation along a great circle route is recommended[ for
reproducibility between spatial reference frames][? and browser
implementations?]. Future specification will require such great circle
interpolation.


> The new sentence for version 4 of the spec. could be:
>
> Interpolated values are required to follow a great circle.
>
>
Nice. Perhaps add route as in great circle route ?
Should there be a hint for a recommended algorithm as well ? I am thinking
about SLERP since it works very well and efficiently between key values
after being converted to geocentric vectors.

-Andreas


> -Mike
>
> On Apr 28, 2016, at 6:14 AM, doug sanden <highaspirations at hotmail.com>
> wrote:
>
> >
> > Andreas,
> >
> >> Alternatively, rather than introducing a new field it may suffice to
> >> simply clarify in the appropriate spec. section that by default great
> >> circle interpolation is recommended for consistency across geoSystems
> >> and across browsers. This could be a recommendation  and not a
> >> requirement but possibly with a qualifier that future spec. revisions
> >> will actually require great circle interpolation.
> >
> > Sounds good.
> > -Doug
> > BSc Surveying Engineering
> >
> >
> >
> > _______________________________________________
> > x3d-public mailing list
> > x3d-public at web3d.org
> > http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <
> http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20160428/3daede19/attachment-0001.html
> >
>
> ------------------------------
>
> Subject: Digest Footer
>
> _______________________________________________
> x3d-public mailing list
> x3d-public at web3d.org
> http://web3d.org/mailman/listinfo/x3d-public_web3d.org
>
>
> ------------------------------
>
> End of x3d-public Digest, Vol 85, Issue 56
> ******************************************
>



-- 
Andreas Plesch
39 Barbara Rd.
Waltham, MA 02453
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://web3d.org/pipermail/x3d-public_web3d.org/attachments/20160428/4deb3705/attachment.html>