PNM to MAP Converter

MAP is an internal raster image format used by ImageMagick, the open-source image processing suite first released by John Cristy at DuPont on August 1, 1990. MAP files store indexed-color (color-mapped) images in ImageMagick's native representation: a color palette (the map) followed by pixel data where each pixel is an index into that palette rather than a direct RGB value. The format provides a compact representation for images with a limited number of distinct colors — each pixel requires only enough bits to index the palette (typically 8 bits for up to 256 colors), compared to the 24 or 32 bits per pixel required by full-color formats. MAP serves primarily as an intermediate format within ImageMagick's processing pipeline, useful when performing operations that benefit from or require palettized representation: color quantization (reducing an image to a specific number of colors), palette manipulation, GIF preparation, and indexed-color analysis. The format is invoked through ImageMagick's standard I/O syntax and can be piped between processing stages without disk overhead. One advantage is direct access to ImageMagick's color quantization and palette management capabilities: MAP format output makes the palette structure explicit and manipulable, enabling workflows where specific palette operations (reordering, remapping, merging) need to be performed between processing steps. The format's integration into the ImageMagick processing ecosystem is another practical strength — any of ImageMagick's extensive image manipulation operations can consume or produce MAP format data, making it a natural intermediate for color-reduction pipelines that ultimately target GIF, PNG with palette, or other indexed-color formats.