GIS file formats

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 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

External links

* [http://data.geocomm.com/helpdesk/formats.html Geo Community - GIS Data Formats]
* [http://gislounge.com/ GIS Lounge]

ee also

*Computer file
*Datum (geodesy)
*GDAL/OGR, a library for reading and writing many formats
*Geoinformation
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