tile

A tile is an image, often a graphics file (such as a .jpg), typically stored in a directory known as a cache. The image is part of a set of tiles that, conceptually, are pieces of a bigger map. How the tiles fit into the bigger map, along with other information, is defined in a tiling scheme. Two tile categories are:

• Tiles in dynamic layers are created during user interaction and can be stored in a cache on either the client or server machine. Where the user pans and zooms affects which tiles are created in this scenario. Technically the tiles might not form a complete map if assembled.
• Tiles in tile cache layers are created before users view the map, often by a developer or GIS data administrator. These tiles are known as pre-processed tiles.