I'm not sure if they're doing it for the wikipedia layer, but one technique I believe Google uses is to use an html image map instead of javascript for onclick and mouseover events. I'm not sure exactly how that would interact with a tile cache, but I imagine it should, and that's probably how Google is doing it.
See http://geoserver.org/display/GEOS/HTML+ImageMap+support and http://mapserver.org/output/imagemaps.html Though maybe performance would be fast enough checking with javascript, there probably is a correct way to do that for what you want to do. Chris tim robertson wrote: > Hi all, > > I am trying to reproduce with openlayers, the same effect that > maps.google.com has with overlaying wikipedia articles. I have a TMS > layer, rendering the tiles server side and also have a web service > providing the info about the pixels on the tile the features are (just > like how google wikipedia overlay works). I am not that great a > Javascript and have been trying to work out where to attach mouseover > and onclick events to the Image Tiles but have not succeeded. I will > need to detect mouseover and mouseout to make sure that I am not > checking against the features for the whole map as the cursor moves > over tiles as this would be much data to check. While a cursor is on > a tile I was planning to check the data array and see if the cursor > was over a feature. > > Can someone please advise me where best to attach mouse events to > individual tiles? I have been playing with various options, all of > which got messy quickly - currently I am trying to subclass > OpenLayers.Layer.TMS and modifying addTileMonitoringHooks. Is this > the correct way to proceed? Any advice is greatly appreciated. > > Many thanks, > > Tim > _______________________________________________ > Users mailing list > [email protected] > http://openlayers.org/mailman/listinfo/users -- Chris Holmes OpenGeo - http://opengeo.org Expert service straight from the developers. _______________________________________________ Users mailing list [email protected] http://openlayers.org/mailman/listinfo/users
