PGMA Files
ASCII PGM Files (Portable Gray Map)

PGMA is a data directory which contains examples of the ASCII PGM (Portable Gray Map) file format. It is a simple grayscale image 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. An ASCII PGM file's magic number is the two characters "P2".
• 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, again in ASCII decimal.
• Whitespace.
• Width * height gray values, each in ASCII decimal, 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.

Example ASCII PGM file:

        P2
        # feep.ascii.pgm
        24 7
        15
        0 0  0  0  0  0  0  0  0 0  0  0  0  0  0  0  0 0  0  0  0  0  0  0
        0 3  3  3  3  0  0  7  7 7  7  0  0 11 11 11 11 0  0 15 15 15 15  0
        0 3  0  0  0  0  0  7  0 0  0  0  0 11  0  0  0 0  0 15  0  0 15  0
        0 3  3  3  0  0  0  7  7 7  0  0  0 11 11 11  0 0  0 15 15 15 15  0
        0 3  0  0  0  0  0  7  0 0  0  0  0 11  0  0  0 0  0 15  0  0  0  0
        0 3  0  0  0  0  0  7  7 7  7  0  0 11 11 11 11 0  0 15  0  0  0  0
        0 0  0  0  0  0  0  0  0 0  0  0  0  0  0  0  0 0  0  0  0  0  0  0
      

ASCII PGM File Characteristics:

• ASCII
• Gray
• 2D
• No compression
• 1 image

Licensing:

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

Related Data and Programs:

PBMA, a data directory which describes ASCII PBM (Portable Bit Map) files.

PGMB, a data directory which describes binary PGM (Portable Gray Map) files.

PPMA, a data directory which describes ASCII PPM (Portable Pixel Map) files.

Reference:

1. the NETPBM homepage.

Sample Files:

• apollonian_gasket.ascii.pgm, a 600 wide by 600 high image of an Apollonian gasket.
• apollonian_gasket.png, a PNG image.
• baboon.ascii.pgm, a 512 wide by 512 high image of a baboon.
• baboon.png, a PNG image.
• balloons.ascii.pgm, a 640 wide by 480 high image of a couple, with balloons.
• balloons.png, a PNG image.
• balloons_noisy.ascii.pgm, a 640 wide by 480 high image of a couple, with balloons, after "salt and pepper" noise has been added.
• balloons_noisy.png, a PNG image.
• barbara.ascii.pgm, a 512 wide by 512 high image of a woman.
• barbara.png, a PNG image.
• body1.ascii.pgm, a 640 wide by 480 high image of a body scan.
• body1.png, a PNG image.
• body2.ascii.pgm, a 640 wide by 480 high image of a body scan.
• body2.png, a PNG image.
• body3.ascii.pgm, a 640 wide by 480 high image of a body scan.
• body3.png, a PNG image.
• brain_398.ascii.pgm, a 720 wide by 486 high image of a visualization of the optical system.
• brain_398.png, a PNG image.
• brain_492.ascii.pgm
• brain_492.png, a PNG image.
• brain_508.ascii.pgm
• brain_508.png, a PNG image.
• brain_604.ascii.pgm, a 720 wide by 486 high image of a visualization of the optical system.
• brain_604.png, a PNG image.
• casablanca.ascii.pgm, a still from the movie "Casablanca";
• casablanca.png, a PNG version;
• coins.ascii.pgm, a 300 wide by 246 high image of 6 nickels and 4 dimes.
• coins.png, a PNG image.
• columns.ascii.pgm, a 640 wide by 480 high image of a person standing by some columns;
• columns.png, a PNG image.
• dla.ascii.pgm, an 800 by 800 image of a structure created by diffusion-limited aggregation.
• dla.png, a PNG version.
• dragon.ascii.pgm, a 475 wide by 460 high image of a cartoon dragon.
• dragon.png, a PNG image.
• f14.ascii.pgm, a 640 wide by 480 high image of an F14 fighter jet.
• f14.png, a PNG image.
• feep.ascii.pgm, a 24 wide by 7 high image that displays "FEEP" in block letters.
• feep.png, a PNG image.
• foliage.ascii.pgm, a 480 wide by 640 high image of foliage.
• foliage.png, a PNG image.
• fractal_tree.ascii.pgm, a photograph of a tree suggesting a fractal structure.
• fractal_tree.png, a PNG version.
• galaxy.ascii.pgm, a 965 wide by 965 high image containing four pictures of the same galaxy at different wavelengths.
• galaxy.png, a PNG image.
• gator.ascii.pgm, a 633 wide by 621 high image of Junior the Alligator.
• gator.png, a PNG image.
• glassware_noisy.ascii.pgm, a 320 wide by 428 high image of glassware, spotted with "salt and pepper" noise.
• glassware_noisy.png, a PNG image.
• hands.ascii.pgm, a 640 wide by 480 high image of hands.
• hands.png, a PNG image.
• handsmat.ascii.pgm
• handsmat.png, a PNG image.
• lena.ascii.pgm a 512 wide by 512 high image.
• lena.png, a PNG image.
• marcie.ascii.pgm
• marcie.png, a PNG image.
• mona_lisa.ascii.pgm, a 250 wide by 360 high image of the Mona Lisa.
• mona_lisa.png, a PNG image.
• mother_daughter.ascii.pgm, a snapshot of a mother and daughter;
• mother_daughter.png, a PNG version;
• mountain.ascii.pgm, a 640 wide by 480 high image of a mountain.
• mountain.png, a PNG image.
• pbmlib.ascii.pgm, a 600x200 image created by PBMLIB.
• pbmlib.png, a PNG image.
• pepper.ascii.pgm, a 256 wide by 256 high image of some peppers.
• pepper.png, a PNG image.
• roi_14.ascii.pgm, a 507 wide by 505 high image an MRI, the 14th in a sequence.11
• roi_14.png, a PNG image.
• saturn.ascii.pgm
• saturn.png, a PNG image.
• screws.ascii.pgm
• screws.png, a PNG image.
• snap.ascii.pgm, a 295 wide by 400 high snapshot of a mother and child.
• snap.png, a PNG image.
• surf.ascii.pgm, a 640 wide by 480 high beach picture.
• surf.png, a PNG image.
• totem.ascii.pgm a 640 wide by 480 high image of a totem pole.
• totem.png, a PNG image.
• tracks.ascii.pgm, a 300 wide by 200 high image that looks like tracks.
• tracks.png, a PNG image.
• venus1.ascii.pgm, a 640 wide by 480 high photo image from the surface of Venus.
• venus1.png, a PNG image.
• venus2.ascii.pgm a 640 wide by 480 high photo image from the surface of Venus.
• venus2.png, a PNG image.
• x31_f18.ascii.pgm, a 640 wide by 480 high image of X31 and F18 aircraft.
• x31_f18.png, a PNG image.

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