Navigating Google Earth

You start your journey through Google Earth from the 3D view of the globe. You can zoom in on any location on the planet, and navigate from place to place around the planet. All it takes is a mastery of Google Earth's navigation controls.

Of course, since you're doing three-dimensional navigation, complete with panning, tilting, and rotating, the navigation is a bit more complicated than what you have with a flat web-based Google map. With Google Earth, you can navigate around the 3D globe by using the navigation controls at the top-right corner of the screen; by using your mouse; or by using select keyboard commands. We'll look at each method in turn.

Navigating with the Onscreen Navigation Controls

Perhaps the easiest way to navigate Google Earth is with the onscreen navigation controls, shown in Figure 20.2. Just click the appropriate control with your mouse, and you can do the following:

• Click the Zoom In and Zoom Out buttons (along with the corresponding slider control) to zoom into or out of the map. Clicking Zoom In displays a closer, more detailed view; clicking Zoom Out displays a further away, less detailed view.

• Click and drag anywhere on the rotation ring to rotate the view. You can rotate the view either clockwise or counterclockwise.

• Click the arrow buttons to move the 3D view up, down, right, or left.

• Click and hold the center control button to use your mouse like a 360-degree joystick. With the center control button held down, moving your mouse in any direction moves the map in the same direction.

• Click the Tilt Up and Tilt Down buttons (or move the corresponding slider control) to tilt the view accordingly.

Navigating with the Mouse

If you're handy with your mouse, you can use it alone (without the onscreen navigation controls) to zoom around Google Earth. In fact, Google Earth offers three different types of mouse-only navigationTrackball, GForce, and Click-and-Zoom. We'll look at each in turn.

Trackball Navigation Mode

The default mouse navigation mode is the Trackball mode. Here's what you can do:

• To zoom in to a specific point, double-click on that point in the viewing pane.

• To generally zoom in, use your mouse's scroll wheel (if it has one) to scroll toward you. You can zoom in smaller increments by holding down the Alt key on your keyboard while scrolling.

• You can also generally zoom in by clicking and holding the right mouse button, and then moving your mouse up (away from you).

• To generally zoom out, use your mouse's scroll wheel to scroll away from you. You can also click and hold the right mouse button, and then move your mouse down (toward you).

• To zoom continuously in or out, hold down the right mouse button, briefly move the mouse up (to zoom in) or down (to zoom out), and then quickly release the mouse button. To stop the zoom, click once in the viewer.

• To move the map in any direction, click and hold the left mouse button, and then drag your mouse in the desired direction.

• To "drift" continuously in any direction, hold the left mouse button down, briefly move the mouse in the desired direction, and then quickly release the mouse button. To stop the drift, click once in the viewer.

• To tilt the view, hold down the Shift key on your keyboard and then move the mouse's scroll wheel up or down. Alternatively, if your mouse has a depressible scroll wheel or middle button, depress the scroll wheel or middle button and then move the scroll wheel up or down.

• To rotate the view, hold down the Ctrl key on your keyboard and then move the mouse either left or right. Alternatively, if your mouse has a depressible scroll wheel or middle button, depress the scroll wheel or middle button and then move the mouse either left or right.

If you use another mouse navigation mode, you can return to the Trackball mode by pressing Ctrl+T.

GForce Navigation Mode

The second mouse navigation mode makes your mouse behave as if it were a joystick. You enter GForce mode by pressing Ctrl+G.

When you're in GForce mode, the navigation cursor changes to an airplane shape. In addition, the effects of any mouse movement become more noticeable the closer you are to the terrain.

To pan left or right, simply left-click the mouse and move the mouse left or right. To tilt the view, left-click the mouse and move it toward or away from you.

To accelerate any movement, right-click and move the mouse forward; to decelerate, right-click and move the mouse back. To stop the current motion, press the spacebar on your keyboard.

Click-and-Zoom Navigation Mode

The final mouse navigation mode is the most limited. To activate Click-and-Zoom mode, select Tools, Options to open the Options dialog box; then select the Navigation tab and check the Click-and-Zoom option.

In Click-and-Zoom mode, you left-click to zoom in and right-click to zoom out. Press the spacebar to stop the zoom.

That's it; there's no other mouse movement possible in this mode.

Navigating with the Keyboard

You can also navigate through any Google Earth view by using your computer keyboard. Table 20.1 details the keyboard navigation commands:

Table 20.1. Google Earth Keyboard Navigation Commands

Navigation	Keyboard Command
Move left	Left arrow
Move right	Right arrow
Move up	Up arrow
Move down	Down arrow
Zoom in	Ctrl+Up arrow or +
Zoom out	Ctrl+Down arrow or -
Tilt up	Shift+Up arrow or PgUp
Tilt down	Shift+Down arrow or PgDn
Rotate clockwise	Shift+Right arrow
Rotate counter-clockwise	Shift+Left arrow
Stop current motion	Spacebar
Reset tilt	u
Reset view to "north-up"	n
Reset both tilt and compass view	r