PGMB Files - Binary Portable Gray Map Graphics Files (original) (raw)

PGMB is a data directory of Binary PGM files, the binary form of the portable gray map PGM format. It is a simple gray map description. The definition is as follows:

• the typical file extension is ".pgm", but an extension of ".pnm" is also occasionally used.
• A "magic number" for identifying the file type. A binary PGM file's magic number is the two characters "P5".
• Whitespace (blanks, TABs, CRs, LFs).
• A width, formatted as ASCII characters in decimal.
• Whitespace.
• A height, again in ASCII decimal.
• Whitespace.
• The maximum gray value, MAXVAL, again in ASCII decimal. MAXVAL must be between 0 and 255.
• A single character of whitespace, typically a newline;
• Width * height gray values, each stored as a plain byte, between 0 and the specified maximum value, separated by whitespace, starting at the top-left corner of the graymap, proceeding in normal English reading order. A value of 0 means black, and the maximum value means white. Characters from a "#" to the next end-of-line are ignored (comments).

Binary PGM File Characteristics:

• binary
• Gray scale only
• 2D
• No compression
• 1 image

Licensing:

The computer code and data files described and made available on this web page are distributed underthe GNU LGPL license.

Related Data and Programs:

PBMB, a data directory which contains examples of binary PBM files, binary Portable Bit Map 2D graphics, black and white;

PGMA, a data directory which contains examples of ASCII PGM files, ASCII Portable Gray Map, 2D graphics;

PPMB, a data directory which contains examples of binary PPM files, Portable Pixel Map (binary) 2D graphics, color;

Reference:

1. the NETPBM homepage.

Sample Files:

• <baboon.pgm>, a baboon.
• <baboon.png>, a PNG version.
• <barbara.pgm>.
• <barbara.png>, a PNG version.
• <bird.pgm>, a bird.
• <bird.png>, a PNG version.
• <buffalo.pgm>, a small herd of buffalo.
• <buffalo.png>, a PNG version.
• <casablanca.pgm>, a still from the movie "Casablanca".
• <casablanca.png>, a PNG version.
• <coins.pgm>, some coins.
• <coins.png>, a PNG version.
• <columns.pgm>, a 640x480 image of a person standing by some columns;
• <columns.png>, a PNG image.
• <dewey%5Fdefeats%5Ftruman.pgm>, a famously erroneous newspaper headline.
• <dewey%5Fdefeats%5Ftruman.png>, a PNG version.
• <feep.pgm>, a simple 7 by 24 example that displays "FEEP" in block letters.
• <feep.png>, a PNG image.
• <ladyzhenskaya.pgm>.
• <ladyzhenskaya.png>, a PNG version.
• <lena.pgm>.
• <lena.png>, a PNG version.
• <lena%5Fnoisy.pgm>, a "noisy" version of the lena image.
• <lena%5Fnoisy.png>, a PNG version.
• <milking.pgm>, a cow being milked.
• <milking.png>, a PNG version.
• <mona%5Flisa.pgm>, the Mona Lisa.
• <mona%5Flisa.png>, a PNG version.
• <pbmlib.pgm>, a file created by PBMLIB.
• <pbmlib.png>, a PNG version.
• <pepper.pgm>, a picture of peppers.
• <pepper.png>, a PNG version.
• <roi%5F14.pgm>, a 507 wide by 505 high image an MRI, the 14th in a sequence.11
• <roi%5F14.png>, a PNG image.
• <snap.pgm>, a snapshot of a mother and child.
• <snap.png>, a PNG version.
• <surf.pgm>, a beach picture.
• <surf.png>, a PNG image.

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Last revised on 22 July 2011.