Thank you Andreas for the info. I will try to load the map once the browser is resized to the original dimension and tell you if there is a difference.
One more question - if the patch or workaround don't work - do you think it's possible to limit the bbox to just the visible area of the map (without extra margins?). I would like to do this either for the Google Layer, or for all the layers - to reduce general load on the server. Thank you, Adrian Andreas Hocevar wrote: > Adrian Popa wrote: >> I asked the same question on Google API forums, and it looks like the >> original Google API doesn't have this limitation. >> > > OpenLayers uses the original Google API, v2.x. Using > OpenLayers.Layer.Google is nothing else than using a GMaps Map > directly, you just access it wrapped by an OpenLayers layer type, not > by the API directly. > > I also do not see a violation of the terms of use. We even make sure > that the Terms of Use link is clickable if we render other layers on > top of Google. > > There is, however, a known issue: if you create your map at a smaller > size and switch from one Google Layer type to another after resizing > it to your big map, tiles will only be loaded for the area of the old > extent. There is a patch that appears to solve this issue. You can try > it: http://trac.openlayers.org/ticket/1797 > > Regards, > Andreas. > >> I did some tests and you can see the results on this thread: >> http://groups.google.com/group/google-maps-api/browse_thread/thread/97d62ed9a85e665e >> >> >> >> I would like to know if there is something that can be done from the >> OpenLayers side, or is this a known limitation. Is OpenLayers >> scraping images from Google, or is it using the API just like any >> other Google Maps client? >> >> Thank you, >> Adrian >> >> Adrian Popa wrote: >> >>> Hello everybody, >>> >>> I would like to share with you my findings about the usage of >>> Google background on very large maps. I have to render a map with >>> the screen resolution of about 4500x3100 (on a wall of screens). It >>> works ok with WFS layers, OSM and even Microsoft Virtual Earth, but >>> I have issues with Google and Yahoo. >>> >>> When I switch to the google layer, the background turns gray and >>> then the browser starts loading the images. After about 130s of >>> loading (there are quite a lot of pictures), I notice that google >>> starts throwing back HTTP 403 errors (Resource temporary >>> unavailable). Just before seeing these errors, some images (the >>> center part of the map) start appearing, but only about 1/4 of the >>> map is drawn. If I wait about 5 minutes, the download process gives >>> up (it still receives HTTP 403 errors all this time), but it >>> displays the rest of the images - which were apparently downloaded >>> before the 403 error appeard. >>> >>> I'm thinking it manages to download most of the visible images + >>> some images in the bbox (which is quite large), but not all the >>> images before getting errors. The problem is the Google API doesn't >>> display what it downloaded, but waits for more images to be downloaded. >>> >>> After analysing the data, I noticed that when the first DNS query is >>> done for the Google cache, it receives back 4 IP addresses. However, >>> only the first 2 IPs are used for traffic - and these 2 IPs start >>> sending back HTTP 403 errors after a while. >>> >>> I would like to know if the following are possible: >>> 1. configure the Google API to use all the IP addresses it receives >>> in the DNS query - maybe this avoids the 403 erros >>> 2. configure the Google API to display the pictures received without >>> waiting for more pictures to download. I'm not sure if this is >>> possible - maybe the images are pipelined through the same >>> connection - and they are shown only when the connection closes. >>> 3. reduce the bbox for the Google Layer - this should be fine for my >>> needs - and maybe avoids the 403 errors. >>> >>> With regard to the Yahoo layer - things are better. It loads faster >>> for the same size (they don't seem to have a "throttling" >>> mechanism), but it only displays the final image when all the bits >>> are downloaded - so it's as fast as the slowest image. Can this >>> behavoir be changed from within OpenLayers? >>> >>> Thanks, >>> Adrian >>> >>> _______________________________________________ >>> Users mailing list >>> Users@openlayers.org >>> http://openlayers.org/mailman/listinfo/users >>> >>> >> >> >> _______________________________________________ >> Users mailing list >> Users@openlayers.org >> http://openlayers.org/mailman/listinfo/users >> > > -- --- Adrian Popa NOC Division Network Engineer Divizia Centrul National de Operare Retea Departament Transport IP & Metro Compartiment IP Core & Backbone Phone: +40 21 400 3099 _______________________________________________ Users mailing list Users@openlayers.org http://openlayers.org/mailman/listinfo/users
