Tiles

Tiles are rectangular slabs of ceramic affixed in a grid arrangement to your bathroom wall! But here we're much more likely to be talking about map tiles: square bitmap graphics displayed in a grid arrangement to show a map. We may also be talking about tiled map data (described below)

Contents 1 Graphical Map Tiles 1.1 Using tiles 1.2 Technical data 1.3 Development 2 Tiled map data 3 Links

Graphical Map Tiles

Map tiles are typically 256 x 256 pixel images. e.g.:

This isn't always the case, For example CloudMade offers OpenStreetMap 64 x 64 pixel images for mobile use, however 256 x 256 pixel images are becoming a de facto standard driven by Google Maps.

A "tileset" typically includes enough tiles to form a very large image, if they were shown all at once, and also several zoom levels. Generally the idea is not to show them all at once, but to display a particular area of the map on a website. Normally this is done using a javascript map library to provide panning and zooming functionality, and request downloading of new tiles as necessary to show the user new areas of the map (a Slippy Map)

Using tiles

• Tiles@Home, a rendering engine that lets lots of clients render small tiles for the slippy map
• Mapnik tiles layer of the slippy map
• Osmarender tiles layer of the slippy map.
• Kosmos Tile Map Server windows tile renderer
• Tile usage policy
• Exporting calibrated maps list tools to have tiles compatible with spécific embedding software

Technical data

• Slippy map tilenames calculate tilenames if you have coordinate
• Estimating Tile Disk Usage.
• Tile water land status[1], index of which tiles are land, or water, on the OSM slippy map, this is a file available in SVN, in the png2tileinfo file.
• List of changed tiles, gets all tiles in a zoom level that have changed in the last 1h to 24h.

Development

• mod_tile Apache module that spawns processes to render mapnik tiles. see mailinglist
• Tile cache, renders maps with mapnik/mapserver/WMS and cache them as tiles.
• Binary tiles see mailinglist

Tiled map data

• QuadTiles, a scheme to make OSM database indexed by tiles
• OJW's tile data server, first implementation of a cacheable data server, that servs data in the same way as the tileserver.
• Tile data server, generic definition of how data served as tiles should work. (written by ojw as well...)

Links

• Switch2OSM, The Basics This page gives some introductory information on the tiles, licence and JavaScript libraries to display the tiles.