---
name: "pamtooctaveimg"
section: "1"
platform: "linux"
package: "netpbm"
version: "10.86.51-2"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/pamtooctaveimg"
---

# pamtooctaveimg(1)

convert a Netpbm image to a GNU Octave image

## NAME

pamtooctaveimg - convert a Netpbm image to a GNU Octave image

## SYNOPSIS

**pamtooctaveimg** \[*netpbmfile*\]

## DESCRIPTION

This program is part of **Netpbm**(1) .

**pamtooctaveimg** reads a Netpbm image as input and produces a  GNU Octave ⟨http://www.octave.org/⟩  image file as output.

An Octave image file (called "Octave's image format" in Octave documentation) is a particular kind of Octave data file.  It describes two matrices:

- •

  the image itself as a list of indexes into a colormap, and

- •

  the corresponding colormap as a list of {red, green, blue} triplets.

An Octave data file is an ASCII text file that you use to import data to Octave.

See the \
  Image Processing chapter ⟨http://www.gnu.org/software/octave/doc/interpreter/Image-Processing.html#Image-Processing⟩  of the GNU Octave manual for details.

**pamtooctaveimg** writes the output Octave image to Standard Output.

## OPTIONS

There are no command line options defined specifically for **pamtooctaveimg**, but it recognizes the options common to all programs based on libnetpbm (See \
  Common Options ⟨index.html#commonoptions⟩ .)

## ARGUMENTS

*netpbmfile* is the name of the file containing the input PNM or PAM image, or **-** to indicate Standard Input.  If you don't specify *netpbmfile*, the input is from Standard Input. **pamtooctaveimg** converts only the first image in the input stream.

## EXAMPLES

```
   % pamtooctaveimg myimage.ppm > myimage.img
   % octave
   > [img,map] = loadimage("myimage.img");
   # (At this point, img is an X by Y matrix and map is a 3 by M matrix.)
   > imshow(img,map);   # Displays img with colormap map
   > [r,g,b] = ind2rgb(img,map);
   # (r, g, and b are now each X by Y matrices of color levels [0 to 1].)
   > [newimg,newmap] = rgb2ind(r,b,g);   # Swap the blue and green channels.
   > saveimage("newimage.ppm", newimg, "ppm", newmap);  # Save as a PPM file.
```

## NOTES

There is no **octavetopam** program.  However, GNU Octave's **saveimage** command can save images in PPM format.

## HISTORY

**pamtooctaveimg** was new in Netpbm 10.39 (June 2007).

## AUTHOR

Copyright (C) 2007 Scott Pakin, *scott+pbm@pakin.org*.

## SEE ALSO

[**octave**(1)](/octave/1.md) , **pam**(1) .

## DOCUMENT SOURCE

This manual page was generated by the Netpbm tool 'makeman' from HTML source.  The master documentation is at

-

  **http://netpbm.sourceforge.net/doc/pamtooctaveimg.html**