Thanks for the input. I will try the MarkerManager and see if that works. I am using EInserts (http://econym.org.uk/gmap/einsert.htm) for my image overlays, but each image is a different URL and I don't want to load images that are not visible. I'm thinking that if I add markers at each point where I want to overlay an image, and manage these markers with a MarkerManager, I can monitor for visibilityChanged events, and when a marker becomes visible, overlay the appropriate image at that point. This should prevent images from being loaded unless they are visible.
On Feb 26, 5:30 am, Mike Williams <[email protected]> wrote: > Wasn't it Andrew Leach (Maps API Guru) who wrote: > > > > >On Feb 26, 6:17 am, canada77 <[email protected]> wrote: > >> I am new to Google Maps and have been learning it quite nicely, but > >> still can't seem to find the answer to 2 questions: > > >> 1) I have a very large polyLine (13,000 vertexes) that has been > >> constructed from driving directions. I want to overlay an image at > >> specific vertexes along the polyLine, but do not want to overlay the > >> images that are not currently visible (causes considerable slowdown). > >> How can I determine, based on the current map view, which vertexes of > >> the polyLine are currently visible? I can then add the GroundOverlay > >> at only the visible vertexes. > > >This is a classic case for something like a Marker Manager. Have you > >tried adding your overlays to a marker manager? (Note: I have no idea > >whether either GMarkerManager or the open-source version can cope with > >anything other than markers, but it's worth a try) > > MarkerManager can cope with any GOverlay that has a .getPoint() Method. > So that's only GMarkers and some custom GOverlays (e.g. ELabels) > > GMarkerManager can cope with any GOverlay that has the unexposed > equivalent of a .getPoint() or .getLatLng() Method. So that's only > GMarkers. > > You might possibly be able to extend the GGroundOverlay class to provide > a .getPoint() method. You'd have to store the information somewhere, > perhaps as a custom Property of the GGroundOverlay when you create it > > GGroundOverlay.prototype.getPoint = function() { > return this.Centre; > } > > var g = new GGroundOverlay(image,bounds); > g.Centre = bounds.getCenter(); > > The problem then would be that when you zoom in, GGroundOverlays that > partially overlap the viewport, but have centres that are outside the > (viewport + padding) might not be displayed. > > --http://econym.org.uk/gmap > The Blackpool Community Church Javascript Team --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Google Maps API" group. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/Google-Maps-API?hl=en -~----------~----~----~----~------~----~------~--~---
