4. OPERATION

Though no previous knowledge of Microsoft Windows is required to operate LCCS, there are some Selection Techniques and Screen Objects the user should become familiar with in order to be able to use the LCCS Actions Panel without problems.

Selection Techniques

• Mouse click: moving the arrow shaped mouse cursor to an object (such as a button or a symbol) and pressing the mouse's left button once.
• Double click: as above, but pressing the left mouse button rapidly twice.

Screen Objects

Typical objects in LCCS, through which the user communicates with the program by making a selection or triggering an action, are:

• Buttons: clicking when the mouse arrow is over a button object triggers the action usually displayed as the button's label (like making a menu choice or quitting a program).
  
  Buttons can take 3 different states:
  • Enabled but not activated: button takes a risen appearance.
  • Enabled and activated: button takes a sunken appearance.
  • Disabled: a button that is disabled cannot be activated; its label shows as lighter grey.
• Combo Boxes: these boxes let the user select from a list of items. By typing the first few characters of a possible choice in the box a matching entry will be displayed and can be selected by pressing <Enter> or by double-clicking the requisite list item. A list of entries unfolds upon clicking the down-arrow at its right hand side. An entry can be selected by double-clicking on it. Should the list be longer than the size of the box, vertical scrollbars are displayed at the right hand side of the box, inviting the user to click on the up or down arrows to see further entries in the list box.
• LCCS Sub-menus: like the Main Menu screen, the LCCS sub-menus let the user branch to further options by clicking on one of the menu buttons.
• The F1 Key/Help: pressing the F1 key in any of the forms/screens of LCCS brings up a context-sensitive Help screen. The effect of pressing the F1 key is the same as clicking on the `Help' button.

The Classification Module Actions Panel appears in the majority of forms/screens of this module. This panel contains 10 buttons that trigger different actions (Figure 11).

FIGURE 11. The Actions Panel in the Classification Module.

The buttons of the Actions Panel trigger the following events:

• End Classification: This button opens a box containing the question "Do you really want to quit Classification?" with the options Yes or No.
• Previous Form/Screen: This button brings the user back to the previous form/screen, with all previously selected buttons visible.
• Legend Menu: This button brings the user to the Legend Module menu.
• Image Database: This button activates stand-alone commercial public domain software for image (e.g., satellite imagery) display.
• Show Classifier Codes: This button opens a window with the relevant classifier options and their corresponding codes. The Close button can be used to close this window.
• Context-sensitive Help: This button opens the Help facility of the current major land cover type the user is in, and which contains all definitions and guidelines for the correct use of the classifiers, modifiers and attributes.
• Show Class: This button opens a new window in which the classifier, modifier and attributes codes used can be viewed, as well as the name of the land cover class. The button in the lower right-hand corner can be used to close this window.
• Write Class to Legend: This button opens a window in which the user has to select one of its options before the class can be successfully written to the Legend Module (for further explanation see Section 5.2).
• Next Form/Screen: This button brings the user to the next level of the classification and is only enabled when all available classifiers in the form have been determined. This button is not available for environmental and specific discipline related attributes.

The buttons are in the enabled position when the action they trigger is valid. The Show Class button in the enabled position indicates that a land cover class has been formed, that is the minimum set of classifiers to define a land cover class has been determined.

In the Legend Module the screen objects consist of buttons that may or may not be followed by a combo box or sub-menu with several options, as described earlier.

For the main Legend menu options Display, Standard Description and Classifiers Used, a report will be shown which can be printed. The same applies for Similarity Assessment in the Translator Module.

In the Translator Module the selection technique consists of clicking on button objects or highlighting a selected item by clicking once on it (especially in list boxes).