ARC ASCII GRID refers to a specific interchange format developed for ARC/INFO rasters in ASCII format.

The format consists of a header that specifies the geographic domain and resolution followed by the actual grid cell values.

Usually the file extension is .asc, but recent versions of ESRI software also recognize the extension .grd. Coordinates may be in decimal or integer format. DD:MM:SS format for geodetic coordinates is not supported.

Used as an exchange or export format due to the simple and portable ASCII file structure.


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  • Cadcorp SIS Desktop Express
  • Cadcorp SIS ActiveX Modeller
  • Cadcorp SIS ActiveX Manager
  • Cadcorp SIS ActiveX Viewer
  • Cadcorp GeognoSIS