[gdal-dev] 1-bit TIFF Images

Frank Warmerdam warmerdam at pobox.com
Fri Dec 19 15:42:51 EST 2008

Markus Neteler wrote:
> Even,
> On Fri, Dec 19, 2008 at 9:26 PM, Even Rouault
> <even.rouault at mines-paris.org> wrote:
>> Matt,
>> The TIFF driver also supports writing 1-bit TIFF images. See NBITS in the
>> Creation Options section.
>> For example: gdal_translate source.tif output_1bit.tif -co NBITS=1
>> When reading a 1-bit TIFF image, GDAL will expand each bit as a byte.
>> When writting a 1-bit TIFF image, GDAL will write 1 as the bit value if the
>> pixel value is non-zero, or 0 as the bit value if the pixel value is zero.
> Just to understand: is a 1-bit TIFF written or a 1-byte TIFF with only
> 1 bit used?


It is written as a true one bit file.  You can even use the special 1bit
compression types (fax3 and fax4).

Best regards,
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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