If the complete map is very large, it may be convenient to split it into more manageable tiles. For example, a world map could be split into 2592 tiles each covering 5 degrees of latitude and longitude. This tiling is used by the DCW.
Tiles can help speed up access if, as is often the case, the user is only interested in a small portion of the whole map. The nature of secondary storage devices such as CD-ROMs and disk drives is that access to a selected record requires a significant amount of time (albeit only a few milliseconds - it's still significant). However, something of the order of a hundred other records may be accessed together with the selected record "for free"; that is, no extra access time. A major part of system design is ensuring that as many as possible of these "free" records are useful rather than just ignored. If the selected record and its associated freebies are all or mostly in the same tile, this would usually be a good design strategy.
One would hope that any user of a Geographic Information System is going to be selective, rather than asking for "everything about everything". Usually the selection will include physical proximity, such as roads, railways and airports in the Isle of Wight. Tiling would help with this. But the selection could be "everything about airports, wherever they are in the world". Inevitably, we are going to have to hit most if not all tiles to answer this, and there won't be many useful freebies.
VPF allows the option of either tiled or untiled. So far, so good. But...Tile disadvantages