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- addtiffo 1.0
- ============
-
-The addtiffo utility is used to add overview pyramids to an existing
-TIFF or GeoTIFF file. Some applications can take advantage of these
-overviews to accelerate overview display performance of large rasters.
-
-This release of addtiffo is primarily intended for compatibility testing
-with applications, and to see if there is interest in a cleaner release
-of the capability ... perhaps incorporation into the libtiff tools
-distribution.
-
-Please feel free to contact me with questions, or problems.
-
-warmerda@home.com
-http://home.gdal.org/~warmerda/
-
-
-Usage
------
-
-Usage: addtiffo [-r {average/nearest} [-subifd]
- tiff_filename [resolution_reductions]
-
-Example:
- % addtiffo abc.tif 2 4 8 16
-
-The numeric arguments are the list of reduction factors to
-generate. In this example a 1/2, 1/4 1/8 and 1/16
-
-
-
-Limitations
------------
-
-See tif_overview.cpp for up to date details.
-
- o Currently only images with bits_per_sample of a multiple of eight
- will work.
-
- o The code will attempt to use the same kind of compression,
- photometric interpretation, and organization as the source image, but
- it doesn't copy geotiff tags to the reduced resolution images.
-
- o Reduced resolution overviews for multi-sample files will currently
- always be generated as PLANARCONFIG_SEPARATE. This could be fixed
- reasonable easily if needed to improve compatibility with other
- packages. Many don't properly support PLANARCONFIG_SEPARATE.
-
- o Overviews are always written as appended IFDs, rather than using the
- ``tree of tree's'' approach using the SUBIFD tag. I wanted to implement
- both, but it isn't currently easy to add a SUBIFD tag to an existing
- main tiff IFD with libtiff. I hope to try this again later.
-
-
-TIFF File Tags
---------------
-
-The results of running addtiffo on a 1024x1024 tiled greyscale file
-with the arguments ``2 4 8 16'' is to add four additional TIFF directories
-appended on the file with the SUBFILETYPE flag to 0x1 indicating the extra
-items are reduced resolution images.
-
-The tiffinfo output of such a file might look like this:
-
-TIFF Directory at offset 0x118008
- Image Width: 1024 Image Length: 1024
- Tile Width: 256 Tile Length: 112
- Bits/Sample: 8
- Compression Scheme: none
- Photometric Interpretation: min-is-black
- Samples/Pixel: 1
- Planar Configuration: single image plane
-TIFF Directory at offset 0x15e1d2
- Subfile Type: reduced-resolution image (1 = 0x1)
- Image Width: 512 Image Length: 512
- Tile Width: 256 Tile Length: 112
- Bits/Sample: 8
- Compression Scheme: none
- Photometric Interpretation: min-is-black
- Samples/Pixel: 1
- Planar Configuration: separate image planes
-TIFF Directory at offset 0x1732b8
- Subfile Type: reduced-resolution image (1 = 0x1)
- Image Width: 256 Image Length: 256
- Tile Width: 256 Tile Length: 112
- Bits/Sample: 8
- Compression Scheme: none
- Photometric Interpretation: min-is-black
- Samples/Pixel: 1
- Planar Configuration: separate image planes
-TIFF Directory at offset 0x17a366
- Subfile Type: reduced-resolution image (1 = 0x1)
- Image Width: 128 Image Length: 128
- Tile Width: 128 Tile Length: 112
- Bits/Sample: 8
- Compression Scheme: none
- Photometric Interpretation: min-is-black
- Samples/Pixel: 1
- Planar Configuration: separate image planes
-TIFF Directory at offset 0x17b40c
- Subfile Type: reduced-resolution image (1 = 0x1)
- Image Width: 64 Image Length: 64
- Tile Width: 64 Tile Length: 64
- Bits/Sample: 8
- Compression Scheme: none
- Photometric Interpretation: min-is-black
- Samples/Pixel: 1
- Planar Configuration: separate image planes
-
-
-Building
---------
-
-You will need a C compiler. You will need to have libtiff already
-built and installed. The provided Makefile should work on most Unix systems.
-A similar file will be needed for Windows, but is not provided.
-
-The CFLAGS and LIBS macros in the Makefile will have to be updated to
-point to the correct location of the libtiff include files, and library.
-
-
-Credits
--------
-
- o Intergraph Corporation for partially funding the work.
-
- o Global Geomatics for partially funding reorganization of the overview
- building ability as a separate utility.
-
- o Orrin Long, and Ed Grissom of Intergraph for explaining what needed to
- be done.
-
- o Max Martinez of Erdas for his discussion of external overviews.
-
- o Atlantis Scientific who supported adding averaging, and some other
- generalizations.
-
- o Frank Warmerdam for writing the bulk of the code.
-
- o Sam Leffler since this only exists because of his libtiff.
-