thanks for this information and recommendation. Is there no way without going into geoserver? If parsing is not the problem, if I set correctly the bounded box of each feature, OL is smart enough to only threat the ones which are visible (and ignore the rest?)?
Christopher Schmidt-4 wrote: > > On Tue, Oct 28, 2008 at 02:17:06PM -0700, darrepac wrote: >> XML is not the most efficient method to transmit data and, on the client >> side, when the application try to open the GML, it slows down heavily the >> machine and it takes age to render. > > The parsing of the GML is unlikely to be the majority of the time here. > Keep in mind that all of that GML is parsed, and then turned right back > into XML to display in your browser (SVG is XML-based). In addition, the > way that OpenLayers works is to constantly update the DOM to change the > properties of that XML. > > In general, you can't display more than about 50 (IE) - 150 (FF2) - 500 > (FF3/Safari3) vectors at once in a browser. Any more than that, and you > run into the rendering slowness that you're seeing. > >> I was thinking to compress or at least put in binary the GML file to be >> more >> efficient. > > This would be significantly less efficient, since Javascript doesn't > have any real way to interact with binary data. > > If you want to try a more efficient transfer format, I recommend > GeoJSON, which transfers in a format which is very lcose to the > browser's internal representation. However, with 4000 features, you're > still going to be completely screwed on performance. You really need to > look into rendering your data with a server: I recommend GeoServer at > this point for beginners, because it's relatively easy to get started > with. > > If you only need to show a few features at a time -- say, you don't mind > limiting yourself to 200 -- you could put the data behind GeoSErver or > some other WFS server, and serve with a maxfeatures setting. This would > limit the number of features displayed at once, and you can generally > choose the ordering (so you display highest population areas first, for > example). This would let you maintain your use of vectors, but limit the > performance headaches, with a "zoom in for more info" (to limit the area > of the map further, and therefore request fewer features). > > Best of luck, > -- > Christopher Schmidt > MetaCarta > _______________________________________________ > Users mailing list > [email protected] > http://openlayers.org/mailman/listinfo/users > > -- View this message in context: http://www.nabble.com/compressed-and-or-binary-GML-to-make-the-client-side-happy-tp20216202p20217165.html Sent from the OpenLayers Users mailing list archive at Nabble.com. _______________________________________________ Users mailing list [email protected] http://openlayers.org/mailman/listinfo/users
