Chapter 5. Graphical User Interface: Basics

Partial Table-of-Contents

This chapter describes how to use the graphical user interface provided with Data Explorer. This interface enables you to create and control the visualization of data. An image is created by applying data, as input, to a visual program. The visual program is a sequence of interconnected functions acting on one or more inputs and producing one or more outputs. Typically, input is user data and output is a realization of that data in the form of an image.

Data Explorer consists of the following windows:

Startup Window	You can use the Startup window to access other windows in Data Explorer.
Visual Program Editor	You can use the Visual Program Editor (VPE) to create and alter visual programs and macros.
Control Panel	You can use Control Panel windows to set and control the input parameters of visual program tools.
Image	You can use the Image window to view an image created by Data Explorer.
Colormap Editor	You can use the Colormap Editor to map colors and opacity to specified data.
Sequencer	You can use the Sequencer to advance through a data series or to step through a changing sequence of input parameters.
Message Window	You can use the Message window to access error and working information about your execution.
Help	You can use the Help window to access online documentation.
Data Prompter	A graphical user interface that simplifies the import of data.
Module Builder	A graphical user interface that simplifies the process of adding modules to Data Explorer.

For information on the Data Prompter, see IBM Visualization Data Explorer QuickStart Guide; on the Module Builder, IBM Visualization Data Explorer Programmer's Reference.

5.1 Starting Data Explorer

To run Data Explorer using a workstation, you must have:

• An account on the workstation
• If the executive portion of Data Explorer is to be executed on a remote workstation, then a .rhosts file in your home directory should contain the name of the machine on which the user interface will run. The permissions for the .rhosts file should be set to 600 (read and write only by the owner).

You can start Data Explorer in any of several modes. In all cases, you must first do the following:

1. Log on to your workstation.
2. Start an X Window System running with the Motif or the appropriate window manager.

If you are going to create, modify, and execute visual programs, start Data Explorer initially in the Visual Program Editor and connect to the executive (server) by typing:

dx -edit [program]

If you plan to execute a previously created visual program, start Data Explorer initially in the Image window and connect to the executive (server) by typing:

dx -image program

dx -menubar program

You may want to start the user interface without connecting to the executive. For example, you may want to work on a visual program or macro, but may not plan to execute it until some later time. In that case, you can start Data Explorer with the following command:

dx -edit -uionly

All of the command line options for Data Explorer are described in C.2 , "Command Line Options".

Using Environment Variables

There are several environment variables that you may find useful to customize Data Explorer. These can be set in your login profile, or set as required.

DXMACROS

The DXMACROS environment variable is a list of the directories in which Data Explorer will look for macros. If you do not specify DXMACROS, you will need to load macros individually, using the process described in 7.2 , "Creating and Using Macros". The directories are searched in the order in which they are specified in the environment variable. If multiple macros with the same name are encountered, the first macro found is used.

An example of the statement setting the DXMACROS environment variable (in the C shell environment) is the following:

setenv DXMACROS /usr/mydirectory/projectAmacros:/usr/mydirectory/projectBmacros

DXDATA

The DXDATA environment variable specifies a list of directories in which Data Explorer will search for data files. If the data you wish to import are in one of the directories specified in the DXDATA environment variable, then you do not need to specify the complete path name to the data in the Configuration dialog box for the Import tool. You can simply specify the file name, and the Import module will look in the specified directories for the data file. The directories are searched in the order in which they are listed in the environment variable; and the first occurrence of the data file is used.

An example of a statement that sets the DXDATA environment variable (in the C shell environment) is the following:

setenv DXDATA /usr/mydirectory/mydata:/usr/group/groupdata

DXHOST

The DXHOST environment variable is the initial machine name of the workstation on which to run the executive. If DXHOST is not specified, then a default of "localhost" is used. See 9.3 , "Connecting to the Server" for more information on how to connect to the server. The host name should be the name that results when you issue the uname -n shell command.

The rest of the environment variables and start-up options are discussed in Appendix C. "Environment Variables and Command Line Options".