GIS file format

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 (e.g., contour lines) form
Shape layers, usually expressed as line drawings, for streets, postal zone boundaries, etc.
Coordinate system descriptions.
One or more data describing the precise shape of the Earth assumed by the coordinates.

Popular GIS file formats

Raster formats

ADRG - National Geospatial-Intelligence Agency (NGA)'s ARC Digitized Raster Graphics
BIL - Band Interleaved by Line (image format linked with satellite derived imagery)
CADRG - National Geospatial-Intelligence Agency (NGA)'s Compressed ARC Digitised Raster Graphics (nominal compression of 55:1 over ADRG)
CIB - National Geospatial-Intelligence Agency (NGA)'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
AutoCAD 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 Geospatial-Intelligence Agency (NGA)'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
Spatial Data File - Autodesk's high-performance geodatabase format, native to MapGuide
GeoJSON - a lightweight format based on JSON, used by many open source GIS packages

Grid formats (for elevation)

USGS DEM - The USGS' Digital Elevation Model
DTED - National Geospatial-Intelligence Agency (NGA)'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
Dual Independent Map Encoding (DIME) – A historic GIS file format, developed in the 1960s
Well-known text (WKT) – ASCII spatial projection description (ESRI uses a *.prj extension)
Well-known binary (WKB) - Binary spatial projection description
World file - Georeferencing a raster image file (e.g. JPEG, BMP)