Abstract : This document provides an introduction and update to the Graphical Plotting System (GRAPS), a plotting utility developed by the Naval Ocean Systems Center for the personal computer. GRAPS provides a convenient, user-friendly tool for the display of engineering and scientific data in a number of conventional plot formats. Linear, semi-log, polar, log-log, Smith, and contour plot formats are among those that can be selected. User-friendly features include auto and user-defined scaling, text editing on graphics screens, and data file management options. Auto and user-defined scaling are new GRAPS features. The polar plots have been significantly improved and the contour plot added. The data file management options have also been expanded. GRAPS will plot any data stored in ASCII files in the GRAPS format. GRAPS is intended to be used as a stand-alone utility for the preparation and display of engineering and scientific data. It is not suitable for inclusion as part of another program, Although subroutines could be stripped out for inclusion in other programs. GRAPS is set up to read data from a disk file written (in ASCII) to a simple format. The disk file may be created by using an editor or word processor. Preferably, a subroutine may be included in the applications program to write the raw data directly to a disk file in the GRAPS format.