Graphics Formats Specifications

Please note most of this info is taken from the Graphics File Formats FAQ by James D. Murray. Some modifications made at University of Missouri-Columbia.


RAW:

Unlike other graphics formats, RAW format has no internal information to describe the data, such as width, height, etc. RAW files are as the name implies: just raw data. For that reason the user must supply these details in order to read the data: width, height, datatype, format (RGB, color-indexed).


HDF - Hierarchical Data Format

Specification: ftp://ftp.ncsa.uiuc.edu/HDF/Documentation/HDF.Specs/

HDF is an object-oriented interchange file format used to transport image data from one machin architecture or operating system to another with no conversion problems or loss of data. Both 8- and 24-bit raster images aresupported, color palettes, and data compression (RLE, Incomp, and JPEG).

The latest version of HDF is 4.1 and comes with a complete library of functions for manipulating HDF files, includeding the netCDF library by Unidata.

Information on HDF is available from The HDF Information Server maintained by the National Center for Supercomputing Applications:

http://hdf.ncsa.uiuc.edu/

The HDF FAQ is located at:

http://hdf.ncsa.uiuc.edu/HDF-FAQ.html

Other HDF-related Web sites include:

The HDU 4.1 User's Guide & Reference Manual:

ftp://ftp.ncsa.uiuc.edu/HDF/Documentation/HDF4.1r2/

Source code for HDF may be FTPed from:

ftp://ftp.ncsa.uiuc.edu/HDF

And HDF-related discussions may also befound on the Usenet newsgroup sci.data.formats and in the FAQ for that newsgroup.Subject: HDF - Hierarchical Data Format

Library version used by IISS 3.3r3


HDFL2

Description:

Extentions of the HDF File format.


vis5d

Official Website: http://www.ssec.wisc.edu/~billh/vis5d.html

Description (from the website):

Vis5D files are five-dimensional arrays in much the same way that GIF images are two-dimensional arrays. The dimensions of Vis5D files are: row, column, level, time and an index into a set of physical fields (e.g., temperature, pressure, humidity, salinity, wind or current velocity, sulfer dioxide concentration, and so on). Row, column and level may be latitude, longitude and altitude, but don't have to be (the dimensions may be abstract, or may be in a non-Cartesian map projection).

The Vis5D system provides highly interactive 3-D visualization of the data in Vis5D files. It is generally used to look at the output of models of the Earth's atmosphere and oceans, but can be applied to any 3-D data sampled on a regular grid.

Library version used by IISS: 4.2


SGI - Silicon Graphics Image File Format

SGI is the native file format of the limage image library found on Silicon Graphics workstations. The limage library provides a set of functions used to read and write SGI images.

The SGI file format is a creation of Paul Haeberli (paul@sgi.com) at Silicon Graphics Computer Systems. The SGI format specification may be found at:

ftp://ftp.sgi.com/graphics/SGIIMAGESPEC

The SGI format is also known as the RGB file format. On SGI workstations you can get info on RGB and the limage library by using the following command:

% man 4 rgb


JFIF - JPEG File Interchange Format

 Type: Bitmap
 Extension: JPG
 Version: 1.02
 Compression: JPEG
 Color Depth: 24-bits
 Maintainer: C-Cube
 Specification: See below

JFIF is a data stream-oriented file format used to define the transmission of JPEG-encoded bitmap data. The specification for JFIF may be obtained directly from C-Cube Microsystems:

C-Cube Microsystems
Attn: Scott Sinclair
Corporate Communications
1778 McCarthy Blvd.
Milpitas, CA 95035
Voice: 408.944.6300
Fax: 408.944.6314

The Independent JPEG Group archive on ftp.uu.net also contains an on-line

copy of the JFIF specification and additional JPEG information as:

ftp://ftp.uu.net/graphics/jpeg/jfif.ps.gz

ftp://ftp.uu.net/graphics/jpeg/jpeg.documents.gz

If you need code to read/write JFIF files and/or a JPEG data stream, then

please use the IJG's JPEG library, available at:

ftp://ftp.uu.net/graphics/jpeg/

Any other questions you have about JPEG will be answered by Tom Lane's

JPEG FAQ, which may be found at:

comp.graphics.misc

ftp://rtfm.mit.edu/pub/usenet/news.answers/jpeg-faq/

Library version used by IISS: 6a


GIF - Graphics Interchange Format

 Type: Bitmap
 Extension: GIF
 Version: 87a, 89a
 Compression: LZW
 Color Depth: 8-bit
 Maintainer: Compuserve
 Specification: 
 ftp://ftp.ncsa.uiuc.edu:/misc/file.formats/graphics.formats/gif87a.doc
 ftp://ftp.ncsa.uiuc.edu:/misc/file.formats/graphics.formats/gif89a.doc

GIF is a data stream-oriented file format used to define the transmission protocol of LZW-encoded bitmap data. GIF images may be up to eight bits (256 colors) in depth and are always compressed. Despite the fact that GIF supports only 8-bits worth of colors, and the multimedia extensions introduced in the 89a release have not been widely utilized, GIF still remains a popular choice for storing lower resolution image data.

The GIF89a specification is available via many BBSs and on-line information

services. You may also obtain the specification directly from CompuServe:

CompuServe Incorporated
Attn: Graphics Technology Department
5000 Arlington Center Boulevard
Columbus, OH 43220
Voice: 614.457.8600, 800.848.8199
FTP: ftp://ftp.compuserve.com/
WWW: http://www.compuserve.com/

Note: Any software created or modified after 01 January 1995 that supports the capability of reading and/or writing GIF files must obtain a patent license agreement from Unisys Corporation. See Part I of the FAQ for more details on the Unisys GIF-LZW license agreements.


TIFF - Tag Image File Format

Bitmapped image format created in 1986 by an industry committee chaired by Aldus Corp. The "tagged" structure of this format makes it extensible and provides for several classes of photometric interpretation (grayscale, RGB, RGBA, color palette) and compression (packBits, JPEG, LZW).

TIFF 6.0 Specification is available online from Adobe as a PDF file.

libtiff library is used for TIFF reading in IISS. It is available online:

ftp://ftp.sgi.com/graphics/tiff/

Library version used by IISS: libtiff-v3.4


PNM - PBM Portable aNy Map file

 Extension: pnm, pbm, pgm, ppm, pbmplus
 Specification: 
 http://www.cica.indiana.edu/graphics/image_specs/pnm.format.txt

MPEG-1 - Moving Pictures Expert Group

 Specification: 
 http://www.iso.ch/meme/JTC1SC29.html
 http://www.iso.ch/cate/d22989.html
 http://www.iso.ch/cate/d22990.html
 http://www.iso.ch/cate/d24450.html
 http://www.iso.ch/cate/d25038.html

The MPEG-1 standard is intended to allow data from non-interlaced video formats having approximately 288 by 352 pixels and picture rates of between 24 and 30 Hz to be displayed directly from a CD-ROM or similar optical storage device, or from magnetic storage medium, including tape. It is designed to provide a digital equivalent of the popular VHS video tape recording format.

Library version used by IISS: Libmpeg 1.2