GIS file formats

From Free net encyclopedia

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

  • ADRG - NIMA Arc Digitized Raster Graphics
  • ASC - Simple ASCII text based formats
  • BIL - Binary Interleave
  • BT - The Virtual Terrain Project's Binary Terrain format
  • CADRG - NIMA Compressed Arc Digitized Raster Graphics (nominal compression of 55:1 over ADRG)
  • CIB - NIMA Controlled Image Base - kind of RPF (Raster Product Format)
  • DEM (USGS) - US Geo Survey Digital Elevation Model
  • DTED - NIMA Digital Terrain Elevation Data
  • ESRI SHP (Shape) - Cartographic vector data with database table lookup association (using DBF and SHX files)
  • GeoTIFF - TIFF variant enriched with GIS relevant metadata
  • GTOPO30 - Large complete Earth elevation model
  • NTF - UK Ordnance Survey
  • SDTS - The USGS' successor to DEM
  • Simple Features - Open Geospatial Consortium Specification for vector data
  • TAB - Mapinfo Table (Associated files: .DAT, .ID, .MAP)
  • UKOS DXF Contour - Contour elevation plots in DXF format
  • VPF - NIMA Vector Product Format - the format of vectored data for large geographic databases.
  • XYZ - Simple point cloud