I can't think of any reason to simplify and then clip as opposed to the reverse, in fact I would expect cases where you'd get a slightly "better" answer by clipping and simplifying.
Ian On Sun, 11 Nov 2018 at 10:07, Andrea Aime <andrea.a...@geo-solutions.it> wrote: > Hi, > following a report of slow vector tiles generation on the list I'm looking > at the vector tiles pipeline builder > and found that topology preserving simplification is done before doing the > clipping. > The use case reported by the user has a single large polygon detailing the > shape of australia, islands included, > that contains 1.5 million vertices. > > I've tried to switch simplification and clipping, doing clipping before, > and the result seems to be much faster, > to the tune of 10 times on an simple "apachebench" benchmark. > > Is there any correctness reason as to why simplification is done before > clipping? > I've tried to dump the same vector tiles twice, with the two operation > flipped, the geometries look pretty > much the same, only in one geometry I get the last point repeated twice at > the end of the ordinate list (comes > out of the current code). > > Cheers > Andrea > > == GeoServer Professional Services from the experts! Visit > http://goo.gl/it488V for more information. == Ing. Andrea Aime @geowolf > Technical Lead GeoSolutions S.A.S. Via di Montramito 3/A 55054 Massarosa > (LU) phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 339 8844549 > http://www.geo-solutions.it http://twitter.com/geosolutions_it > ------------------------------------------------------- *Con riferimento > alla normativa sul trattamento dei dati personali (Reg. UE 2016/679 - > Regolamento generale sulla protezione dei dati “GDPR”), si precisa che ogni > circostanza inerente alla presente email (il suo contenuto, gli eventuali > allegati, etc.) è un dato la cui conoscenza è riservata al/i solo/i > destinatario/i indicati dallo scrivente. Se il messaggio Le è giunto per > errore, è tenuta/o a cancellarlo, ogni altra operazione è illecita. Le > sarei comunque grato se potesse darmene notizia. This email is intended > only for the person or entity to which it is addressed and may contain > information that is privileged, confidential or otherwise protected from > disclosure. We remind that - as provided by European Regulation 2016/679 > “GDPR” - copying, dissemination or use of this e-mail or the information > herein by anyone other than the intended recipient is prohibited. If you > have received this email by mistake, please notify us immediately by > telephone or e-mail.* > _______________________________________________ > Geoserver-devel mailing list > Geoserver-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geoserver-devel > -- Ian Turton
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