Hello everybody, I am working with the Google API (v2) from within OpenLayers.
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. 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. 4. How is the limitation of access to google data implemented? Is there a limit of bytes in an amount of time? Is there a maximum number of requests per host? If there is no option in tuning the existing API, who would I have to contact for a legal agreement to lift this limitation for some IPs? Thank you for your time, Regards, Adrian P.S. I posted a similar message on the OpenLayers mailing list, but I suspect I can get more help from here. -- 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.
