> I think it may be true with shapes which are not discretized. @Michaël, Is this a job for Monsieur Bézier's curves? :-)
Larry On Thu, Nov 6, 2008 at 4:56 PM, Michael Michaud <[EMAIL PROTECTED]>wrote: > > Hum... consider two lines that do barely touch. You have an intersection >> point. If the transformation changes the intersection points, it would >> mean that it's possible that after reprojection the two lines do >> not touch anymore, thereby changing their topological relationship. >> >> I have vague memories of continuous transformations never altering >> the topological relationships between the transformed geometries, >> but I may have dreamt about it :) >> > I think it may be true with shapes which are not discretized. But we always > use a discrete representation and we generally suppose that coordinates can > be linearly interpolated between points. But interpolation function should > not be the same in geodetic space and in projected space (the precise image > of a straight segment - or a geodetic line - on Earth's surface is > generally not a straight segment in the projected plan). The error is hidden > as far as we do not need to interpolate, but can appear as soon as we need > to interpolate (as in intersection computation for example). > > Michaël > > Cheers >> Andrea >> >> > _______________________________________________ > jts-devel mailing list > [email protected] > http://lists.refractions.net/mailman/listinfo/jts-devel > -- http://amusingprogrammer.blogspot.com/
_______________________________________________ jts-devel mailing list [email protected] http://lists.refractions.net/mailman/listinfo/jts-devel
