| shx | ArcView Shape Index |
| sidx | SharpMap Spatial Index |
| slpk | ArcGIS Desktop Scene Layer Package |
| smp | Idrisi Raster Format Color Table |
| smw | SuperMap Desktop GIS Workspace |
| smwu | SuperMap Desktop GIS 6R Workspace |
| sos | SOSI Spatial Data |
| sosi | SOSI Spatial Data |
| sou | OpenMap Source Data |
| spx | ArcGIS Geodatabase SPX File |
| ssf | Trimble SSF Data |
| stn | ArcView Geocoding Standardization |
| strk | GeoLogger GPS Track Data |
| style | ArcGIS Style File |
| sup | SOCET SET Support File |
| svy | AGPS-Shape Pro Data Point |
| sxd | ArcScene Document |
| sxf | GIS Storage and eXchange Format File |
| sxw | SuperMap Desktop GIS XML Workspace |
| sxwu | SuperMap Desktop GIS 6R XML Workspace |
| tab | MapInfo Table Document |
| tat | ArcView Text Attribute Table |
| tdmb | Trimble Outdoors Navigator Map Bundle Data |
| ter | Map Maker Terrain File |
| tfw | ArcGIS TIFF World File |
| tfwx | ArcGIS Approximate Affine Transformation Data |
| tifw | ArcGIS TIFF World File |
| timestamp | ArcGIS Geodatabase Timestamp File |
| tlw | TripLogik TL1000 RAW Data |
| tpk | ArcGIS Tile Data Package |
| tpo | Topo Explorer Map |
| tqm | Traqmate Data File |
| trip | Garmin Nuvi Trip Data |
| tro | Visual Topo Document |
| tsd | TNTmips TileSet Definition Data |