| 13o | RINEX Observation Data |
| 19o | RINEX Observation Data |
| 3dd | ArcGlobe Document |
| 3tf | MapInfo 3D Graph Template |
| a2e | ArcGIS Option Data |
| aat | ArcInfo Line Data |
| adc | XMap Output Data |
| adf | ArcInfo Coverage Data |
| adp | SIA dataMap GIS Export |
| adrg | ARC Digitized Raster Graphics |
| aep | ArcExplorer Project |
| aer | Chart Navigator Pro Aeronautical Raster Map |
| aet | Chart Navigator Pro Map Data |
| afp | XMap Flight Plan Statistic Data |
| agb | NAVFone Data |
| agf | ESRI Atlas GIS File |
| agr | ESRI ArcGIS Ascii Grid |
| agv | ArcGIS Video Metadata |
| aid | MapInfo Access ID File |
| aih | ArcGIS Optional Index |
| ain | ArcGIS Optional Index |
| air | SeeYou Airspace Data |
| alg | ER Mapper Algorithm Data |
| ama | ArcGIS ArcMap Animation Data |
| amf | Anquet OMN Digital Map |
| an1 | Street Atlas USA Draw File |
| anr | DeLorme Street Atlas Route Data |
| apa | ArcGIS ArcPad Applet |
| apf | ArcGIS ArcPad Profile Data |
| apl | ArcGIS ArcPad Layer Data |
