Monday, August 29, 2005

Attribute Info and Zoom (and a peak at GTViewer 5.0)

GTViewer provides the Attribute Info and Zoom commands for reviewing feature attributes and navigating the view. These two commands have a great deal of overlap in their overall functionality and with the upcoming GTViewer 5.0, the difference between these two commands will blur even further. The Attribute Info and Zoom commands will be discussed in detail by this blog posting so that they can be fully utilized by the users; also, the new functionality they will offer in GTViewer 5.0 will be introduced.


Traditionally, the Attribute Info command has been used to select a feature and retrieve tabular information and linked files. However, the command also provides the ability to zoom in, zoom out, and go back to the previous view.


The Zoom command has traditionally been solely for navigation by providing the ability to center the view on a mouse click and providing the ability to zoom in, zoom out, and go back to the previous view.

The only difference between the Attribute Info and Zoom commands is that the click will retrieve feature attribute in one and center the view in the other. Both command can Zoom In, Zoom Out, and go to the Previous view.

Use either of the command is very simple. Once in the selected mode, a single click of the left mouse button (or pressing the stylus to the screen) with no dragging of the cursor will result in the action specific to the active command:

  • The Zoom command will center the view on the point clicked on.
  • The Attribute Info command will retrieve tabular information and linked files for the feature under the click. If more than one feature is present at the click location, a popup list will allow the user to select the specific feature to review.

The different navigation actions are interpreting from the movement of the cursor (by a mouse or stylus). The diagram below shows the action that will be taken by the cursor action in both Attribute Info command and Zoom command.

To perform a navigation action, click the left mouse button (or press the stylus on the screen) and drag the cursor in a direction. Releasing the mouse button (or lifting the stylus) will initiate the navigation action. If the Center mark is the click-down location, the quadrant the cursor is dragged into determines the navigation action:

  • Zoom In - Drag Down and Right – The area inside the box you draw with the cursor (between the click-down location and the current location) will be fit to the current view size. The smaller the box you draw, the more zooming will be performed. The cursor will change to a Plus sign “+” when in Zoom In mode.
  • Zoom Out - Drag Up and Right - the farther you drag, the more you zoom out). The cursor will change to a minus sign “-“ when in Zoom Out mode and the farther you drag the cursor in this mode, the larger the minus sign cursor appears and the more you will zoom out.
  • Previous View - Drag Up and Left – The View/Location History command can be used to see what path the user has taken to get to the current view. Each previous view command executed, will step back through this list until it is at the first view when the dataset was opened. The cursor will change to a left facing arrow when in Previous View mode.
  • Cancel - Drag Down and Left – In case you start a zoom out, zoom in, or previous view, you can change your mind and stop the action before the view is manipulated. You can also press the Esc button to cancel an action that has begun. The cursor will revert back to the default Northwest arrow when the Cancel is mode is active.

While this concept of dragging the cursor into the different quadrants to perform a specific action may at first seem unnecessarily complicated and may be somewhat different from other applications you have used, it has proven to be much more efficient than other techniques and is very easy to get used to. It may not be readily obvious that the benefit of the modes combined into a single command is that you do not have to continuously change your mode to perform a range of navigation functions. For example, if you had a different commands for Zoom In, Zoom Out, Previous View, and Window Center (4 buttons on the toolbar), imagine how many times you would have to change modes to navigate to a specific feature. Each time you change modes, you must travel back to the toolbar, find the button to press, then go back to the view where you want to perform the action, then go back to change the mode again, and again. With the navigation modes all combined into one command, the user never has to go back to the toolbar to change modes and is immediately able to perform the navigation operation without any additional interaction with the software.

The Zoom mode is a nice all-in-one tool for navigating the view. If you use the Attribute Info mode, you trade the Window Center for a Feature Review while still maintaining the ability to Zoom In, Zoom Out, and go to the previous view. For me, this mode has always been the ultimate multi-function mode since you never have to change mode to review attributes and navigate. In fact, the Zoom mode could be done away with completely with minimal loss to the application’s functionality. However, GTViewer 5.0 will provide some new functionality to breathe a little life into the Zoom mode and it may be the ultimate mode for the future.

GTViewer 5.0 provides a subtle yet dramatic change to way you can perform basic tasks in GTViewer. The right-mouse menu has always been available to provide a quick popup menu of commonly used commands right at the mouse cursor.

Now, the right-mouse menu will search for any features present at the click and will pre-pend any features found to the beginning of the right-mouse menu. Also, if any feature has a linked file associated with it, the linked file will also be displayed under the feature in the right-mouse menu. By select a feature in the menu, the Attribute Info dialog will be displayed. By selecting a linked file, the associated file will be launched immediately (without going through the Attribute Info dialog, selecting the Link tab, and activating the link).

With the enhanced right-mouse menu, it no longer matters what mode you are in if you want to review a feature or see a linked file. So, you can stay in Zoom mode and perform all of the navigating and reviewing you want with more navigation actions than the Attribute Info mode can provide and still maintain the ability to review a feature without changing modes.

The Attribute Info command has also been enhanced for GTViewer 5.0. It now provides the ability to jump directly to a linked file without going through the Attribute Info dialog. If a feature has a linked file associated with it, you can launch the linked file by holding in the Ctrl key when the left-mouse button is clicked on the feature. If more than one detail is available, a pick list will be provided.

Both of these enhancements in GTViewer 5.0 provide even more flexibility to the way you operate in GTViewer. By making information easier to get to and optimizing the user workflow to perform common tasks, GTViewer again caters to the user’s need for a more productive environment.

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