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To change the subject a little, a while back I heard talk of SAFE adopting Idevio's lossless compression technology. I believe this throws wavelet maths at geometry to park unwanted coordinates off to one side, giving you reversible generalisation. The output is multi-resolution geometry which unpacks itself appropriately in the client depending on viewing scale. The target audience is people wanting zillions of features deliverable via web or file to any size client. If enough people ask for it you might get it! Bruce. Bruce Harold Geographic Information Solutions <http://www.gis.co.nz> www.gis.co.nz Ph. (64) (0) 9 537 3247 Mb. (+64) (0) 21 2995995 _____ From: [email protected] [mailto:[EMAIL PROTECTED] On Behalf Of jamison_leach Sent: Wednesday, 4 April 2007 8:37 a.m. To: [email protected] Subject: [fme] Re: "lossless" line generalization Good afternoon, In order to test the LineGeneralizer's results (using the Douglas algorithm and a zero tolerance), I first used the Densify transformer to add vertices to my lines. These densified lines were then processed by the LineGeneralizer, and I hoped all the vertices added by Densify would be removed. However, LineGeneralizer appears to only remove some of the added (unnecessary) vertices. I haven't yet figured out why this is. Regards, JD --- In [EMAIL PROTECTED] <mailto:fme%40yahoogroups.com> com, "mark2atsafe" <[EMAIL PROTECTED]> wrote: > > I think the LineGeneralizer will do what you need if you use the > Douglas(-Poiker) algorithm and set the tolerance to zero. When the > tolerance is zero it should just remove intermediate points on a > straight line, without changing the shape of the feature. > > Regards, > > Mark > > > --- In [EMAIL PROTECTED] <mailto:fme%40yahoogroups.com> com, "jamison_leach" <hemsidan@> wrote: > > > > Good afternoon, > > > > Does anyone know if there is there a way to remove unnecessary > > vertices from lines? By unnecessary, I mean vertices that contribute > > nothing to the shape of the line. If we were to compute an angle at > > such vertices, it would be 180 degrees. Using the Generalizer > > transformer would eliminate non-redundant vertices and change the > > shape of my lines, which is undesirable, even if the shape would > > change only slightly. > > > > Many thanks, > > J.D. Leach > > U.S. Census Bureau > > >
