Yes, as John says, it works really well to render on the fly and then cache.
I have one map with lots of polygons (>3000) and lots of points (>32,000) that does not use cache full tiles at: http://maps.webfoot.com/demos/election2008 There is another set of maps that does use caching, and even though that uses an older codebase that is significantly slower to render any given tile, with caching it feels quite zippy. http://maps.webfoot.com/RaceOverlays.php The disk space usage isn't that bad. I uh (*blushes slightly*) have never gotten around to setting up an eviction policy, and it's been running for about three years. Most of the world is rural, and rural areas are pretty boring at zoom levels closer in than 8 or 9. (Why didn't I do full tile caching for the elections map? Because I let people change the colour mapping, and I didn't want people to be so used to snappy response with caching that they'd get discouraged by a slow response when they changed the colour mapping. It's all about managing expectations.) And while I recommend the gd library, if you want to draw polygons with it, you might need to patch it. I describe the problem and link to the bug (which has a link to my patch): http://www.webfoot.com/blog/2007/08/12/robobait-gd-library-bug-horizontal-lines/ On Feb 11, 7:42 am, "maps.huge.info [Maps API Guru]" <[email protected]> wrote: > There is a Perl example using the GD library as part of a workshop I > gave last February that renders tiles "on the fly" from a database. As > Mike mentions, the key to doing this is coming up with a key structure > that allows quick retrieval of the data from the database without > using any spatial searches. One method is using the tile numbers as > the index, but the problem with this is, again as Mike mentions, data > that crosses from one tile to another. > > http://www.usnaviguide.com/ws-2008-02/presentation.pdf > > The dynamic tile page: > > http://www.usnaviguide.com/ws-2008-02/demotilecookies.htm > > The entire presentation on YouTube (84 minutes): > > www.youtube.com/watch?v=IYqfT9i1las > > Another thing about data at zoom level 19 to consider. How many people > are going to be looking at the middle of some deserted part of > Australia at that level of detail? Probably few if any will ever view > many of the billions of tiles you need for complete coverage. As > DuckySherwood(the first to use this method I know of) postulated a number > of years ago, why create tiles that will never be used? Instead, > create them on the fly and cache them. The first user of the tile may > experience some delay while it is being built, but subsequent viewers > of the data will see near instantaneous results. The way to achieve > this is to use a tile server program that first checks to see if there > is a tile already there and if not, dynamically builds it, stores it > and serves it to the user. > > -John Coryat > > http://maps.huge.info > > http://www.usnaviguide.com --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
