SAND Internet Browser

User manual

A Browser window is divided into several panels stacked vertically. These are (from top to bottom):

• The command area, containing menus and buttons for several actions: First and Next retrieve the first/next tuple satisfying the currently set scan order and predicate; File provides various basic operations such as Open or Close [the current relation] or Quit [the browser]; Display presents a menu of several activities connected to the graphical display, such as clearing it or drawing spatial features; Style allows changes of drawing attributes such as line or fill color.
• The Scan order panel contains a button that triggers the exhibition of several "pop-up" dialog boxes, and a message area that displays the currently selected scan order parameters. Each dialog box corresponds to parameters to be used when the relation is being scanned with the help of one of the indices defined for it.
• The Conditions panel allows specification of a predicate to be used to evaluate the query (the predicate must follow the syntactic rules of Tcl expressions).
• The info panel indicates the current line and fill colors (the colors that will be used next time the user chooses any displaying operation from the Display menu). It also contains a choice which allows the user to change the current relation (the relation that all the queries are executed with respect to).
• The graphical display panel is the drawing area where spatial features are input and output. At any given moment of the interaction, the current value of the relation's spatial attribute is displayed in this area and highlighted by an orange rectangle. Most of the other user interface components which hold a spatial feature value support input by drawing on the graphical display. The display can also be panned (with the help of the horizontal and vertical scrollbars) and zoomed in and out. The zoom in and zoom out operations are available through left and middle click respectively, the right click finds the nearest object to the location of the click from the current relation and makes it the current tuple.
• The info line will show various messages during the browser execution.
• The tuple display panel contains a series of labeled entry boxes, one for each attribute in the schema of the relation. These are updated to reflect the value of the current tuple.
• The layer display lists all the layers available for this relation. Clicking on the individual entries in this list toggles displaying of the respective layers in the graphical display area on and off.