Andrea, I don't want to tease you but I am afraid you have overseen something.
Imagine a data source which is able to do a NON preserve topology generalization. This data source hast to supports both hints. Hints.GENERALIZATION_DISTANCE Hints.PRESERVERE_TOPOLOGY For a renderer client, it works because Hints.PRESERVERE_TOPOLOGY==false. A WFS client uses Hints.PRESERVERE_TOPOLOGY==true and this does not work. What should the data soure do ?. Throw an exception ?. Andrea Aime writes: > Christian Müller ha scritto: >> To say it in your words >> Hmmmmmmmmm.......... there is something missing. >> Scenario 1) >> A data source supports Hints.GENERALIZATION_DISTANCE but does NOT support >> Hints.PRESERVERE_TOPOLOGY. >> This indicates that the data source has some precalculated, topological >> correct generalizations which it will return. The final generalization is >> handled by the renderer/wfs client. > > Nope. There is a misunderstanding about the PRESERVE_TOPOLOGY hint here. > PRESERVE_TOPOLOGY = true -> you must return topologically correct data > PRESERVE_TOPOLOGY = false -> you _can_ return topologically incorrect > data (who in his sane mind would _order_ a data source to ruin the > topological correctness of the data if there is no advantage in doing > so?) > > If you data source has precalculated topologically correct data it will > always work, you can return topologically correct data even if the > hint told you that you _can_ return topologically incorrect data > as well (you can, not you must). > >> Scenario 2) >> A data source supports Hints.GENERALIZATION_DISTANCE AND supports >> Hints.PRESERVERE_TOPOLOGY. >> This indicates that the data source returns already generalized >> geometries, no final generalization >> takes place in the renderer/wfs client. >> Unfortunately, this implies that the data source must be able to do both >> types of generalization, > > No, wrong, see above. I did not read the rest of the mail since the > whole discussion seems to be based on the wrong assumptions. > > Cheers > Andrea > > > -- > Andrea Aime > OpenGeo - http://opengeo.org > Expert service straight from the developers. ------------------------------------------------------------------------------ _______________________________________________ Geotools-devel mailing list Geotools-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geotools-devel
