MPLOT is an interactive visualisation program for the X-Window System. It is used to visualise two dimensional slices of ocean model data. Interaction with the software is done through the use of various X11 windows e.g text areas, menus, dialog boxes and control panels. At any stage a hardcopy PostScript file of the displayed image can be produced.
MPLOT may also be compiled with an UNIRAS extension which permits more advanced contour plots of the displayed data to be produced. Executables compiled with the UNIRAS extension are called UMPLOT (see Appendix 2). The main body of this document describes features which are common to both MPLOT and UMPLOT
Section 1.2: X-Window Graphical User Interface
Text Areas: Text Areas are windows which allow the user to enter information required by the program. A text window is activated by clicking on the text prompt line using the left hand mouse button. Each text area has an ACCEPT and a CANCEL button.
Menus: Menus are vertically aligned lists of options. A menu is displayed on the screen by clicking the left hand mouse button, in the main window area, or by selection of an option from another menu. A menu item is selected by placing the cursor over the item required and clicking the left hand mouse button.
Dialog Boxes: Dialog boxes are used to send information to the user. This may be an instruction, a warning or an error message. Each dialog box contains a Continue button. To close a dialog window, click on this once using the left hand mouse button.
Control Panels: Control Panels are windows which may contain several input areas. The control panels are used when it is necessary to initialise several variables for the next event , for example, the PostScript control panel [refer to section 9.1 PostScript]. A control panel contains an Accept button and a Cancel button. The Accept button, if selected, will execute the action selected by the user using the variables initialised in the control panel.
Section 1.3: Initialising Environment Variables
MPLOT/UMPLOT run on Unix workstations . Both programs use the following environment variables
Site values are set at compile time [Section 0:Release Notes and Installation]. Individual users may override the site settings , if desired, by setting their own values within their active environment. This enables, for example, users to personalise their own set of colour files.
The Hierarchial Data Format (HDF) is a multi-file format supported by the National Centre for Supercomputing Applications (NCSA) for archiving and transfer of data between machines. Information in a HDF file maybe stored using a number of data formats, but for the purpose of OCCAM data archiving, the Scientific DataSet Interface was choosen. The Scientific DataSet (SDS) interface provides routines for storing multi-dimensional arrays of gridded data. One advantage of the HDF system, is that additional information maybe stored as part of the file or as part of a dataset ( attributes ). Several attributes were defined for OCCAM datasets in order to specify information regarding their creation. A list of global (file) and local (dataset) attributes can be found in Appendix 2. Further documentation about HDF files for archiving ocean model data can be found in Appendix 1.