G-Vis : Thinwire Geographic Visualization System

G-Vis Demo Instructions

The user interface is composed of a tree hierarchy of windows, called telewindows (or telewin, for short). Each telewin can have multiple children, and the user has control over opening and closing telewins. (Only leaves of the tree can be closed). A child telewin shows a more zoomed in view of the geography than its parent. If the portions of the geography shown in the child and parent overlap, then a black rectangle in the parent indicates the location of the child. All the telewindows are placed inside a window called the Applet Panel. The telewindows can be resized and moved within the Applet Panel.

The first telewindow is called the Root Window. It shows the entire map in the lowest detail, and it has special restrictions: no zooming, panning, resizing, or closing. (It may be iconified.)

You can get help from within the program by pressing the question mark button. Here is a summary of the basic operations.

  1. Open a new telewin as the child of an existing telewin by right-clicking the mouse on the existing telewin.
  2. Close a telewin with the standard close icon in the upper right corner.
  3. Detach or attach (let the applet panel float or fix the applet panel to the browser).
  4. Pan (translate the view in a telewin) by dragging with the left mouse button.
  5. Zoom in or out in a telewin by clicking the buttons, or by moving the slider.
  6. Jump to a new location by clicking on that location in the parent telewin.
  7. Center a telewin's parent at the telewin's own center by clicking on the button.
  8. Feature labels pop up when the mouse pauses over a feature; labels can be turned off from the Options menu.
  9. Teleport -- which lists locations that you can directly jump to.
  10. My Places -- you can enter your own favorite sites and this will be remembered for the future. [Note: we may post your favorite sites for other users to visit.]

Additional Information:

  1. The scale of a telewindow is given above the slider. The bar shown is equivalent to the number of meters or kilometers shown. The smallest scale (i.e. highest detail) is 250 meters per 100 pixels.
  2. There are several levels of detail, and these are indicated by the color bar under the slider. Zooming in or out within a particular color only changes the size of the features shown; zooming in or out to a different color on the color bar changes the actual set of features shown.
  3. Each telewindow always has a smaller scale than its parent. When zooming, the scales on multiple telewindows might change to insure that this condition is always true.
  4. At the bottom of the applet panel, on the left side, are five letters that are either red, for "on", or gray, for "off". These letters represent various states that the program can be in.
  5. Also at the bottom of the applet panel is an ongoing display of the cumulative data transmission: The numbers for polylines and polygons are for processed data, not the raw TIGER data.

Initially, the applet only loads the data that is actually displayed. As you pan around, the data for displaying the new areas is dynamically loaded from the server. We are working on the design and implementation of techniques that will greatly speed up this process.