IMHO: because getLocalUpVector() is a member of EllipsoidModel, it should respect the ellipsoid settings and return a vector orthogonal to the surface.
Wojtek, I am not sure what you mean about killing the relationship b/w the up vector and the east/north vectors. Can you clarify this? Glenn Waldron : Pelican Mapping : http://pelicanmapping.com : +1.703.652.4791 On Tue, Jun 30, 2009 at 4:55 PM, Wojciech Lewandowski <[email protected] > wrote: > Hi Ronald and all interested, > > I think you have touched a very delicate subject... But since You started > it I will add my 2 pennies [image: Winking smile emoticon] > > I agree that local coordinate system produced by EllipsoidModel has a bit > unusual orientation. I did some investigation one day and it looks like this > local coordinate frame is not tangent to ellipsoid surface. Instead local > coordinate orientations correspond to tangent surface on a perfect > sphere. But at least these orientation vectors in such spherical coordinate > system are consistent. Local up vector is orthogonal to east and north > vectors. If you change upVector method you will kill this relationship. > > I would be happy if we could use local space that would be tangent to > ellipsoid but this would require not only changing localUp method but also > changing worldToLocal and localToWorld methods. However, this sounds to me > like problems with former osgDEM and VPB generated databases.... > > Frankly, I don't know what is best solution here. Maybe someone > with GIS experience could provide some guidance. I think that we should > ask for the answers to few simple questions : how the "up" vector should > be defined ? As vector opposite to gravity vector ? Or as vector orthogonal > to local east and north vectors ? Should the local north and local > east vectors be tangent to the ellipsoid or not ? > > Cheers, > Wojtek Lewandowski > > *From:* Maarseveen, R.A. (Ronald) van <[email protected]> > *Sent:* Tuesday, June 30, 2009 8:07 PM > *To:* [email protected] > *Subject:* [osg-submissions] EllipsoidModel::computeLocalUpVector > > Hi all, > > In OpenSceneGraph-2.8.2-rc2 in the file include/osg/CoordinateSystemNode > > Computing an up vector on an ellipsoid should take the geographic latitude > into account. > The geographic latitude is the angle between the normal to ellipsoid > surface and XY-plane. > > The original code computes an upvector for a sphere. > > Best regards, > Ronald van Maarsveen > > This e-mail and its contents are subject to the DISCLAIMER at > http://www.tno.nl/disclaimer/email.html > > ------------------------------ > > _______________________________________________ > osg-submissions mailing list > [email protected] > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org > > _______________________________________________ > osg-submissions mailing list > [email protected] > > http://lists.openscenegraph.org/listinfo.cgi/osg-submissions-openscenegraph.org > >
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