gouldtoppm

Convert a Gould scanner file to a PPM image

$ gouldtoppm [path/to/file.gould] > [path/to/output.ppm]

gouldtoppm [-image] [gouldfile]

-image
    Treat input as image file instead of plot file (default for stdin).

Gouldtoppm is a specialized utility from the Netpbm graphics toolkit.

It reads Gould VDC (Variable Data Coordinate) files, originally produced by Gould Inc. scanners and plotters, and converts them to the versatile PPM (Portable Pixmap) format.

VDC files exist in two types: plot files with vector data that gouldtoppm rasterizes, and image files containing direct pixel data, often in a 16-color palette. By default, input is treated as a plot file, but the -image option handles image files explicitly. When reading from standard input, image mode is assumed automatically.

This tool is essential for archiving and processing legacy scientific or technical images, enabling compatibility with contemporary software like GIMP or ImageMagick through PPM support. Output is always sent to stdout as raw PPM, ideal for piping into other Netpbm filters or file redirection.

The conversion preserves the original resolution and color depth where possible, making it reliable for historical data recovery.

Very strict input validation; fails abruptly on malformed VDC files.
Plot files render vectors to raster, potentially altering appearance vs. originals.

Input from gouldfile or stdin.
Writes binary PPM image to stdout.

gouldtoppm image.vdc > image.ppm
gouldtoppm plot.vdc > plot.ppm
cat scan.vdc | gouldtoppm > scan.ppm

Developed as part of the Netpbm project by Jef Poskanzer starting in 1988; gouldtoppm added in early 1990s to support Gould hardware formats used in scanning/plotting.

ppm(5), pbm(5), pgm(5), netpbm(1)