A GIS file format is a standard of encoding geographical information into a file. They are created mainly by government mapping agencies (such as the USGS) or by GIS software developers.
Metadata often includes:
- Elevation data, either in raster or vector form (e.g., contours)
- Shape layers, usually expressed as line drawings, for streets, postal zone boundaries, etc.
- Coordinate system descriptions.
- One or more datums describing the precise shape of the Earth assumed by the coordinates.
Popular GIS file formats
Raster formats
- ADRG – National Imagery and Mapping Agency (NIMA)’s ARC Digitized Raster Graphics
- BIL – Band Interleaved by Line (image format linked with satellite derived imagery)
- CADRG – National Imagery and Mapping Agency (NIMA)’s Compressed ARC Digitised Raster Graphics (nominal compression of 55:1 over ADRG)
- CIB – National Imagery and Mapping Agency (NIMA)’s Controlled Image Base (type of Raster Product Format)
- Digital raster graphic (DRG) – digital scan of a paper USGS topographic map
- ECW – Enhanced Compressed Wavelet (from ERMapper). A compressed wavelet format, often lossy.
- ESRI grid – binary and ASCII raster formats used by ESRI
- GeoTIFF – TIFF variant enriched with GIS relevant metadata
- IMG – ERDAS IMAGINE image file format
- MrSID – Multi-Resolution Seamless Image Database (by Lizardtech). A compressed wavelet format, often lossy.
- JPEG2000 – Open-source raster format. A compressed format, allows both lossy and lossless compression.
Vector formats
- Geography Markup Language (GML) – XML based open standard (by OpenGIS) for GIS data exchange
- DXF – Contour elevation plots in AutoCAD DXF format
- Shapefile – ESRI’s open, hybrid vector data format using SHP, SHX and DBF files
- Simple Features – Open Geospatial Consortium specification for vector data
- MapInfo TAB format – MapInfo’s vector data format using TAB, DAT, ID and MAP files
- National Transfer Format (NTF) – National Transfer Format (mostly used by the UK Ordnance Survey)
- TIGER – Topologically Integrated Geographic Encoding and Referencing
- Cartesian coordinate system (XYZ) – Simple point cloud
- Vector Product Format – National Imagery and Mapping Agency (NIMA)’s format of vectored data for large geographic databases.
- GeoMedia – Intergraph’s Microsoft Access based format for spatial vector storage.
- ISFC – Intergraph’s Microstation based CAD solution attaching vector elements to a relational Microsoft Access database
- Personal Geodatabase – ESRI’s closed, integrated vector data storage strategy using Microsoft’s Access MDB format
- File Geodatabase – ESRI’s geodatabase format, stored as folders in a file system.
- Coverage – ESRI’s closed, hybrid vector data storage strategy. Legacy ArcGIS Workstation / ArcInfo format with reduced support in ArcGIS Desktop lineup
Grid formats (for elevation)
- USGS DEM – The USGS‘ Digital Elevation Model
- DTED – National Imagery and Mapping Agency (NIMA)’s Digital Terrain Elevation Data
- GTOPO30 – Large complete Earth elevation model at 30 arc seconds
- SDTS – The USGS’ successor to DEM
Other formats
- Binary Terrain – The Virtual Terrain Project’s Binary Terrain format
- Well-known text (WKT) – ASCII spatial projection description (ESRI uses a *.prj extension)
- Well-known binary (WKB) – Binary spatial projection description
