Interesting, I was just thinking along these lines, but doing the pyramid outside of GeoServer instead of inside, see http://sourceforge.net/mailarchive/forum.php?thread_name=49C94E81.40205%40opengeo.org&forum_name=geowebcache-devel
GeoServer would just need a generalization method, and then GWC would build up the pyramid - either on the fly or pre-seeded. Could be interesting to bend it back around, so you could make the vector cache pyramid in GWC, and then use it back in GeoServer. We're approaching similar things on the raster side as well. Chris Christian Müller wrote: > Hi Michael, I am already using the JTS simpliefier. I am storing my features > in DB2, use the db2-ng module and have > Features like > > BorderEurope > BorderEurope_100 (Generalised 100 m) > BorderEurope_1000 (Generalised 1000m) > > and so on > > Andrea: > > The urgent need is WMS, but it should work for WFS too. Uisngthe SLD is a > possiblity, but > this is not really transparent. At the moment I have to convince my users > that layout has to be done with SLDs and not > downloding the whole stuff and working with ARCGis. Live is hard enough. > > My idea was to do a FeatureSource implementation containing the base feature > source and all generalisation feature sources, > delegating most of the methods to the base feature source, but the problem > is that I need > 1) the reqeusted Envelope > 2) the pixelDimension > to decide which generalisation to use. > > And I have no idea how to transport this information from the WMS GetMap > request to new FeatureSource implementation. > > A second brute force idea was to implement a geoserver plugin as described > here. > http://geoserver.org/display/GEOSDOC/3+A+Simple+PlugIn > defining an own service to find the correct generalisation and do an WMS > redispatch. > Nasty, but would work > > Any ideas > christian > > > Andrea Aime writes: > >> Christian Müller ha scritto: >>> Do we have something like pyramids for for vector data ? >>> >>> What I mean is having a FeatureSource (say, the boundary of Europe having >>> 100 000 vertices) and drawing the boundary on a 640x480 image. >>> I really do not need 100 000 points and therefore I make some >>> generalizations, each as its own feature source, minimizing io traffic >>> and cpu usage. >>> >>> It would be nice to have a (read only) FeatureSource as a Wrapper for all >>> the generalizations (best design pattern would be a composite), which >>> selects the proper generalization (depending on world and pixel size) and >>> returns a much smaller number of vertices. >>> >>> It is the same concept as we have for image pyramids (I think, >>> AbstractGridCoverageReader has the logic built in). >>> >>> Opinions ? >> Are you talking WMS or WFS? WMS already does on the fly generalization >> before rendering. And if you want to use pre-generalized data, >> you can, just store multiple geometric columns in your database, >> and use scale dependent rules to decide which geometry to use. >> This effectively allows for using pre-decimated geometries, thought >> of course it would be nicer if the datastore hid the extra columns >> and could decide which one to pick automatically based on a generalization >> hint. >> >> WFS wise, we're thinking to work on something like that as well. >> WFS 1.1 >> specification allows to return not only attributes, but also >> functions over attributes. At the moment they are not supported, >> but we are looking into what amount of work it would take >> to support them. Once that is working, we could have a >> generalize(geom, distance) function that does generalization, >> and also plays fully by the WFS rules. >> >> Opinions? >> Cheers >> Andrea >> >> -- >> Andrea Aime >> OpenGeo - http://opengeo.org >> Expert service straight from the developers. > > > > ------------------------------------------------------------------------------ > Apps built with the Adobe(R) Flex(R) framework and Flex Builder(TM) are > powering Web 2.0 with engaging, cross-platform capabilities. Quickly and > easily build your RIAs with Flex Builder, the Eclipse(TM)based development > software that enables intelligent coding and step-through debugging. > Download the free 60 day trial. http://p.sf.net/sfu/www-adobe-com > _______________________________________________ > Geotools-devel mailing list > Geotools-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geotools-devel -- Chris Holmes 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
