Convert hpgl to pgm

What is the difference between .hpgl and .pgm?

Description: The HPGL file format, standing for HP Graphics Language Plotter File, is a specialized file type developed by Hewlett-Packard. It is primarily used for controlling plotter devices, which are printers that draw images with lines instead of dots, making them ideal for engineering and architectural drawings. HPGL files contain a series of two-letter instruction codes followed by parameters that direct the plotter's drawing operations, such as moving to a point, drawing a line, or selecting a pen.; A PGM file is a grayscale image file saved in the portable gray map (PGM) format and encoded with one or two bytes (8 or 16 bits) per pixel. It contains header information and a grid of numbers that represent different shades of gray from black (0) to white (up to 65,536). PGM files are typically stored in ASCII text format, but also have a binary representation.