The control words appearing in the extra specifications of the GPLOT (PLOT) operations can be defined by the user. All such definitions are saved in a text file (Survo device driver) and maintained easily by the SAVEP and LOADP operations of Survo. The default device driver for the GPLOT operation is given as crt_dev=<name_of_file> in the auxiliary file SURVO.APU in the Survo directory. Most of the specifications in GPLOT schemes can be given like GRID=([RED][line_width(2)]),XY where the driver dependent part has always the form ([...][...]...[...]), The words in brackets (like [RED] and [line_width(2)]) have to be defined in the driver. To override the default driver, use INCLUDE=<name_of_driver> in your GPLOT scheme. New drivers can be built by using default drivers as models. P = More information on plotting