geographic data files or gdf is an interchange file format for geographic data. in contrast with generic gis formats, gdf provides detailed rules for data capture and representation, and an extensive catalog of standard features, attributes and relationships. most recent extension expand applicability further towards pedestrian navigation, 3-d map rendering, and advanced driver assistance systems (adas). gdf is commonly used for data interchange in many industries such as automotive navigation system, fleet management, dispatch management, road traffic analysis, traffic management, automatic vehicle location. originated as a flat plain-text file, gdf is not intended to be used directly for any large scale geographic application and normally requires conversion into a more efficient format. consumability has been increased with most-recent developments for xml and sql renditions. the maps in gdf format are provided by many map vendors such as navteq, tomtom, mapscape bv, geosmart, automotive navigation data, autonavi and navinfo. ==standardisation== gdf is an international standard that is used to model, describe and transfer road networks and other geographic data. the standard was initially drawn up by cen in co-operation with digital map providers, automotive and electronic equipment manufacturers. the outcome of these standardisation efforts (cen gdf 3.0, or env14825:1996) has formed the major input to a global standard created by iso/tc204 sub working group 3: * iso gdf 4.0, formally referred to iso14825:2004, now replaced by * iso gdf 5.0, formally referred to iso14825:2011. however, despite the existence of an iso gdf standard, the nature of model abstractions as well as semantic interpretations and proprietary content extensions lead to interoperability issues between flavors of gdf map products from different vendors. in practice the gdf files are not fully interchangeable due to vendor specific extensions. to this end, gdf5.0 provides major improvements in terms of extended meta data and flags for signalling implementation choices. ===the new gdf5.0=== the specifications of gdf5.0 were developed and compiled between 2001 and 2008, involving experts from australia, canada, czech republic, france, germany, japan, republic of korea, the netherlands, and the united states of america. extensive activities towards harmonization with iso/tc211 standards were undertaken. gdf 5.0 was published in july 2011. major gdf5.0 enhancements include uml model migration & refinements; harmonization with linear referencing and geo-spatial web standards; support for 3-d content and time coordinates; comprehensive character set and [[
GIS_file_formats Navigation Satellite_navigation_systems