On Mon, Dec 22, 2008 at 1:43 PM, Bill Magee <[email protected]> wrote: > I don't do *nix but on WinXP the typical allocation size for large disks > is 4kb (and I assume other file systems will do similar). Any tile under > 4kb (lots of them) will occupy this 4kb regardless.
Back when ti...@home stored its images in one file each, I think the sysadmins chose a block size of 512 bytes for exactly that reason. That would have been on Linux with ReiserFS though, so probably doesn't help for your app. The replacement scheme was http://wiki.openstreetmap.org/wiki/Tiles%40home/Tileset_as_one_file which puts 1366 tiles in each file (along with compression for various types of blank tiles) - apparently it doesn't take long to extract the PNG data for any given tile from such files. Depending on what you're rendering, you may find that most tiles are blank (more so for specialist layers like bus routes, less so for layers with autogenerated content on like contours) so it's worth considering those when calculating the expected disk usage. (plain-colour 'blank' tiles might be sea or forest etc., as well as just empty land, depending on your rendering) _______________________________________________ dev mailing list [email protected] http://lists.openstreetmap.org/listinfo/dev
