# INGR --- Intergraph Raster Format

This format is supported for read and writes access.

The Intergraph Raster File Format was the native file format used by Intergraph software applications to store raster data. It is manifested in several internal data formats.

## Reading INGR Files

Those are the data formats that the INGR driver supports for reading:

- 2 - Byte Integer
- 3 - Word Integer
- 4 - Integers 32 bit
- 5 - Floating Point 32 bit
- 6 - Floating Point 64 bit
- 9 - Run Length Encoded
- 10 - Run Length Encoded Color
- 24 - CCITT Group 4
- 27 - Adaptive RGB
- 28 - Uncompressed 24 bit
- 29 - Adaptive Gray Scale
- 30 - JPEG GRAY
- 31 - JPEG RGB
- 32 - JPEG CYMK
- 65 - Tiled
- 67 - Continuous Tone

The format "65 - Tiled" is not a format; it is just an indication that the file is tiled. In this case the tile header contains the real data format code that could be any of the above formats. The INGR driver can read tiled and untilled instance of any of the supported data formats.

## Writing INGR Files

Those are the data formats that the INGR driver supports for writing:

- 2 - Byte Integer
- 3 - Word Integers
- 4 - Integers 32Bit
- 5 - Floating Point 32Bit
- 6 - Floating Point 64Bit

Note that writing in that format is not encouraged.

## File Extension

The following is a partial listing of INGR file extensions:

.cot | 8-bit grayscale or color table data
.ctc | 8-bit grayscale using PackBits-type compression (uncommon)
.rgb | 24-bit color and grayscale (uncompressed and PackBits-type compression)
.ctb | 8-bit color table data (uncompressed or run-length encoded)
.grd | 8, 16 and 32 bit elevation data
.crl | 8 or 16 bit, run-length compressed grayscale or color table data
.tpe | 8 or 16 bit, run-length compressed grayscale or color table data
.lsr | 8 or 16 bit, run-length compressed grayscale or color table data
.rle | 1-bit run-length compressed data (16-bit runs)
.cit | CCITT G3 or G4 1-bit data
.g3 | CCITT G3 1-bit data
.g4 | CCITT G4 1-bit data
.tg4 | CCITT G4 1-bit data (tiled)
.cmp | JPEG grayscale, RGB, or CMYK
.jpg | JPEG grayscale, RGB, or CMYK

Source: http://www.oreilly.com/www/centers/gff/formats/ingr/index.htm
The INGR driver does not require any especial file extension in order to identify or create an INGR file.

## Georeference

The INGR driver does not support reading or writing georeference information. The reason for that is because there is no universal way of storing georeferencing in INGR files. It could have georeference stored in a companying .dgn file or in application specific data storage inside the file itself.

## See Also:

For more information:

- Implemented as `gdal/frmts/ingr/intergraphraster.cpp`.
- www.intergraph.com
- http://www.oreilly.com/www/centers/gff/formats/ingr/index.htm
- File specification: ftp://ftp.intergraph.com/pub/bbs/scan/note/rffrgps.zip/