Contents
The road database is a vector map of some area of interest. Street names or numbers and house numbers are encoded as geographic coordinates so that the user can find some desired destination by street address.
Points of interest (waypoints) will also be stored with their geographic coordinates. Point of interest specially includes fuel stations, public parking, and "parked here" (or "you parked here").
Contents can be produced by the user base as their cars drive along existing streets (Wi-Fi) and communicating via the internet, yielding a free and up to date map.
Format
Formats are uniformly proprietary; there is no industry standard for satellite navigation maps. The map vendors Tele Atlas and NAVTEQ create the base map in a standard format GDF but each electronics manufacturer compiles it in an optimised, and usually proprietary format. GDF is not a CD standard for car navigation systems. GDF is used and converted onto the CD-ROM in the internal format of the navigation system.
Media
The road database may be stored in solid state read-only memory (ROM), optical media (CD or DVD), solid state flash memory, magnetic media (hard disk), or a combination. A common scheme is to have a base map permanently stored in ROM which can be augmented with detailed information for a region the user is interested in. A ROM is always programmed at the factory; the other media may be preprogrammed, downloaded from a CD or DVD via a computer or wireless connection (bluetooth, Wi-Fi) or directly used utilizing a card reader.
