1-Introduction

There are four groups of commands:

1. Commands to do with display devices : D***
2. Commands to plot from datasets and manipulate datasets in a way that affects the plotting : G***
3. Low level plotting commands : G_***
4. Shortforms for some of the more common invocations of GSET

Also the low level commands can be used in conjunction with any sub-package and only require a device to be open.

The basic plotting command, GDRAW, can be used standalone to open a device, plot a dataset, then close the device again. Alternatively if a device is already open (eg. opened by DOPEN) then it will plot the dataset to that device and leave it open. If a dataset is to be drawn repeatedly then it will be more efficient to load it into the system using GLOAD. After the initial plot this will reduce overheads considerably. When finished with it can be released again with GCLOSE.

Complex plots can be created and manipulated with GMULTI. This can be used to create a dataset containing the data for multiple plots and also to determine how those data are combined and arranged.

The command GSET is used to set plotting attributes and generally control the form of plotting, not just for data being plotted with GDRAW, but also for other sub-packages like Image Processing.