 |
 |
 |
 |
 |
 |
 |
 |
 |
|
|
|
||||||||
|
||||||||||
|
Digital Earth > TerravisionTM > User Guide > Tcl/Tk > View Menu The View MenuModeThe Mode submenus let you switch the current viewer between a 2D (pan and zoom) type interface, or a 3D (full 6 degree-of-freedom) paradigm. The current viewer type is displayed in the status bar at the bottom of the screen, and can also be toggled by pressing the '2' and '3' keys on the keyboard.Viewpoint ControlsThe Viewpoint Controls window lets you move yourself through the terrain in a number of different manners. There are three different movement modes.
Viewpoint StatusThe Viewpoint Status window simply tells you your current position and orientation in the world. Your location is given as a WGS84 geocentric coordinate, i.e. an (x, y, z) offset from the center of the planet in units of meters. 
Viewpoint BookmarksThe Viewpoint Bookmarks facility lets you save viewpoints that you like and then return to them easily at a later juncture. In order to create a bookmark, you simply click over the "Add View" button and enter a name for that viewpoint. To remove a viewpoint, you click over it in the list of viewpoints and then select the "Remove View" button.
In order to go to a viewpoint that you previously bookmarked, simply double-click over its name in the Viewpoints list, or single-click and then select the "Set View" button. Note that TerraVision displays all of the bookmarks for all of the datasets that you have loaded for a particular viewer. To rename a viewpoint, you can edit the name of the bookmark in the text field to the top right of the window, then click on the "Rename" button. The "animate" option controls whether TerraVision will create an animation to the selected viewpoint bookmark when you select Set View, or if it should simply jump there immediately. N.B. if you create a bookmark called "Origin" (case insensitive), then TerraVision will use this bookmark to set the initial view when you first open the 3-D viewer. Your bookmarks are stored in the file viewpoints.xml in your configuration directory. This file is updated every time you add or remove a viewpoint - you do not need to explicity save the bookmarks. Goto AddressThe Goto Address feature implements a gazetteer service within TerraVision. That is, the ability to translate a street or city address into a latitude/longitude coordinate. Currently, you can enter any city name in the world and TerraVision will attempt to resolve its physical location and then jump to that location. We use the Where On Earth gazetter service in order to perform this task.
Goto Lat/LongThe Goto Lat/Long feature lets you jump to a specific WGS84 latitude/longitude location in the world, and also to set the relative orientation at that point. To represent latitudes in southern hemisphere, or longitudes in the western hemisphere, use negative numbers. For example, in the screenshot below, when the user clicks on the "Goto Lat/Long" button, TerraVision will jump to the location 3.344 degrees west and 57.738 degrees north. The heading, pitch, and roll angles are all relative to the target location. So, setting these to 0, -90, and 0 respectively will make the viewer look straight down at the surface of the planet.
Goto OriginThis option will return the viewer to the initial, or origin, viewpoint. This is actually calculate as the origin viewpoint for the lowest resolution dataset loaded. The origin viewpoint for a particular dataset can be explicity set by defining an "Origin" bookmark, otherwise it will be calculated automatically be TerraVision. This feature can also be accessed by pressing the 'O' key on the keyboard.
Copyright ©2000 SRI International. All rights reserved. |
|||||||||||||||||||||||||||||||||||||||||||||||
