CALS --- CALS Type 1

(GDAL >= 2.1)

CALS Type 1 rasters are untiled back and white rasters made of a 2048-byte text header in the MIL-STD-1840 standard, followed by a single datastream compressed with CCITT/ITU-T Recommendation 6, aka Group 6, aka CCITT FAX 4. CALS Type 1 rasters are one of the 4 types of formats described by MIL-PRF-28002C (this standard is now deprecated). Other types are not handled by this driver.

This driver supports reading and creation of CALS Type 1 rasters. Update of existing rasters is not supported.

A CALS dataset is exposed by the driver as a single-band 1-bit raster with a 2-entry color table. The first entry (0) is white (RGB=255,255,255) and the second entry (1) is black (RGB=0,0,0).


The following metadata items might be exposed by the driver (or read from the input dataset to generate a cor

Creation issues

Only single band 1-bit rasters are valid input to create a new CALS file. If the input raster has no color table, 0 is assumed to be black and 1 to be white. If the input raster has a (2 entries) color table, the value for the black and white color will be determined from the color table.

See Also: