Google Earth

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Google Earth is a program that lets you easily view the Earth in three dimensions with a number of standard datasets, including imagery, streets, and web-based information. This tutorial will help you become familiar with using Google Earth, including the creation of your own sets of places and tours.

This tutorial is written for version 6.2 of Google Earth, but most of it applies to earlier versions, also.

Topics	Procedures
Genesis with Google Earth Navigating Around Google Earth Layers of Information Adding Your Own Content Decorating Content Descriptions	Controlling Terrain Quality Navigation Controls Summary Creating a Placemark Organizing Placemarks in a Folder Playing Tours of Placemarks Creating a Path

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Genesis with Google Earth

Google Earth is a program that lets you fly around the Earth with a surprising degree of detail and ease of use.

It is actually several programs with increasingly sophisticated features. The least-capable version, which is still very useful, is free to install and use.

You can download all versions from http://earth.google.com.

Install Google Earth in the usual way, and start it up in the usual way, and you’ll see the Earth appear:

The different parts of the program are:

• The Display pane, where you can view the Earth and navigate around it; note the Navigation Controls in the upper right corner.
• The Sidebar, containing:
• The Search pane, where you can type in the names of locations that you want to visit;
• The Places pane, which stores locations of interest and other features;
• The Layers pane, allowing you to turn on and off various types of geographic information.
• The Toolbar above the Display pane, containing tools to change your view of the Earth and create your own places of interest.

We’ll shortly look at each of these.

There is also a row of tools just above the main pane; most of these we won’t use in this basic tutorial.

One characteristic of Google Earth that you should keep in mind: it pulls its information off of the Internet as you view it, so you need a network connection to see anything new. This includes close-ups of the Earth, which are actually separate sets of data. But if your computer goes off-line, the older information you already viewed is still available in the program’s cache.

Note: In the following instructions, “click” means “left-click” on a two-button mouse. On a Mac with a single-button mouse, a “right-click” can be accomplished by holding down the key Ctrl and then clicking.

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Navigating Around Google Earth

Google Earth provides a complete set of controls for simulating a three-dimensional view of the Earth.

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Zooming In to or Out of the Earth

You can get a closer look at the Earth by zooming into (approaching) it, or get a larger view by zooming out of (receding from) it.

There are three basic ways to zoom:

• Scroll:

• Using a mouse with a scroll wheel, turn it away from you to zoom in, and towards you to zoom out.
• Using a Macintosh trackpad, drag two fingers away from you to zoom in, and towards you to zoom out.

If this seems counterintuitive, you can reverse this setting:

• On Windows, click on the menu Tools and then on the menu item Options…;
• On Macintosh, click on the menu Google Earth and then on the menu item Preferences…;

In either case, in the tab Navigation, check the checkbox  Invert Mouse Wheel Zoom Direction.

• Navigation Controls:


 
Zoom
Control

The navigation controls will appear automatically when you move the cursor into the upper right corner of the Display pane.

The slider at the bottom is the zoom control, and you can click on the + end to zoom in, and the – end to zoom out (see the image at the right).

You can also drag the slider in the middle to continuously zoom in or out.

If you want the navigation controls to always show or never show, you can change their behavior by clicking on the menu View and then on the menu item Show Navigation, and finally on the appropriate submenu item.

• Keyboard:

Page Up	zoom in
Page Down	zoom out

Note that in each of these cases, the location on the Earth that is at the center of the screen will remain at the center (more or less).

Zooming in Google Earth is not simply magnification; you are given the view you would see if you were positioned at a certain distance above the Earth’s surface, which is called the eye altitude. The primary difference is that your horizon (the edge of what you can see) will decrease as you approach the Earth.

The eye altitude is shown in the lower right corner of the Display pane; notice how it changes as you zoom in and out.

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Moving Around the Earth

The simplest way to change your view of the Earth is to move or, more precisely, translate across it, as if you were walking forward or backward or stepping left or right.

This is equivalent to rotating the Earth, but it’s hard to imagine this when you are close to its surface.

As with zooming, there are three basic ways to move around:

• Click-and-drag:

With the mouse, point at the Earth and you’ll notice that the cursor changes to a hand.

Then click on the Earth and drag it opposite to the direction you want to move — imagine you’re spinning a real globe.

One cool thing you can do is click on the Earth, drag it a short distance, and then without stopping release the mouse, as if you are “throwing” the Earth; this will make you drift across the Earth continuously.

Click anywhere in the Display pane to stop the drift.

• Navigation Controls:


 
Translation
Control

The navigation controls will appear automatically when you move the cursor into the upper right corner of the Display pane.

The lower disk (with the hand) is the translation control (see the image at the right). You can click on one side of it in the direction you want to move.

You can click and hold for continuous movement, and even slide around the edge to smoothly change directions.

The closer to the edge of the disk, the greater or faster the motion.

• Keyboard:

If necessary, click in the Display pane (since the keyboard can also be used to move around in the other panes). The, use one of the four arrow keys (or the ADSW keys if you are left-handed) to move your view in the direction you want to go:

		↑ W	forward
← A	left	↓ S	backward	→ D	right

You can also use two arrow keys at a time to move in the direction midway between them.

If you also hold down the Alt key (on Windows) or the Option key (on Macs), the speed of your motion will be much slower.

In addition to displaying images of the Earth’s surface, Google Earth also shows you information about the surface location the cursor points at, at the bottom of the Display pane:

• latitude and longitude (north-south and east-west geographic coordinates), and
• elevation (distance above sea level) .

Try moving the hand across the Earth and notice how these values change.

The geographic coordinate grid can be displayed by clicking on the menu View, and then the submenu Grid.

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Flying to a Location on the Earth

Quite often you will want to zoom in to a particular location that might be visible but isn’t at the center of the screen.

You can quickly fly to a location by double-clicking on it; Google Earth will center it and also zoom in to that position by a fixed amount.

If you right-double-click on a location, Google Earth will center it but zoom out by a fixed amount.

As with drifting, click anywhere in the Display pane to stop the fly-to motion.

You can regulate this process more directly by right-clicking in the Display pane, whereupon crosshairs and/or a double-arrow will appear; then move the mouse forward or backward to zoom as much as you want.

When you are close enough to the Earth, about 300 miles above its surface, the Street View icon will appear in the navigation controls. If you drag it to a particular location, Google Earth will zoom all the way into the surface of the Earth and enter the Street View mode.

In much of the developed world and in many highly urbanized areas, Street View will include actual photographs of the street, as if you were standing on the ground looking around you. If such photos aren’t available, it will construct a horizontal view from aerial photographs.

The navigation controls described previously will work more or less the same way in Street View (but not the ones to be described subsequently).

You can can return to Google Earth's normal aerial photographs by clicking on the button Exit Street View in the upper right corner of the Display pane; however, it will remain close to the ground, in a tilted view of the Earth's surface.

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Searching for Locations

Google Earth’s pane Search understands location information in a number of different formats, and will fly to the locations it finds.

For example, try these:

• Massachusetts
• Amherst, MA
• College St. and S. Pleasant St., Amherst, MA
• Amherst College
• A pair of numbers representing geographic coordinates (latitude and longitude):
• 42° 22' 12" N, 72° 31' 3" W
• 42 22 12 N, 72 31 3 W
• 42.37, -72.5175 (order is significant if you don’t include N, S, E, or W)

If you don’t remember what these last pairs of numbers represent, you can read more about it here.

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Orbiting a Location on the Earth

In addition to moving in straight lines, Google Earth also provides controls to orbit around a central location.

This capability lets you, for example, look at the sides of a mountain rather than simply looking down on it from above.

To best illustrate orbiting, you should first translate your position so that you are above a mountain or valley, for example Mt. Monadnock in southwestern New Hampshire (pictured, with Amherst in the distance), or Mt. Everest on the Nepal-China border.

As with translational motion, there are three basic ways to orbit (for best effect you should be relatively close to the ground):

• Click-and-drag:

Hold down the Shift key and click-and-drag the mouse to the left or right to orbit the central location counter-clockwise or clockwise, respectively.

Note that crosshairs will appear to clearly mark the central location.

This change in orientation is called the heading, and is measured from north (0°) clockwise to east (90°) to south (180°) to west (270°), and back to north (360°)

Hold down the Shift key and click-and-drag the mouse away from or towards you, to orbit backward/downward or forward/upward, respectively, around the central location.

This change in orientation, called the tilt, is constrained between the horizontal (90°) and vertical (0°) directions, respectively.

• 
   
  Orbit/
  Rotation
  Controls

  Navigation Controls:

With the mouse, point at the upper right corner of the Display pane, whereupon the navigation controls will appear.

The upper disk is surrounded by a compass ring, with the letter N to indicate north (i.e. towards the North Pole of the Earth); you can click-and-drag this ring to orbit clockwise or counter-clockwise, i.e. change your heading.

Click on the N to orbit until north is directly forward.

There is no display control for tilting (orbiting backward/downward or forward/upward) in the latest version of Google Earth.

• Keyboard:

If necessary, click in the Display pane. Then use the arrow or ADSW keys while holding down the Shift key:

		Shift ↑ Shift W	orbit forward/upward
Shift ← Shift A	orbit counter-clockwise	Shift ↓ Shift S	orbit backward/downward	Shift → Shift D	orbit clockwise

There are also a couple of special keystrokes you can use to reset your orientation:

• N will orbit you towards the north (the same as clicking on N in the compass ring);
• R will “right” you by orbiting you towards the north and orbiting you forward/upward to be above the central location.

Try orbiting around an elevated feature after you’ve enhanced the terrain quality, and notice the difference in how it looks.

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Rotating Your View of the Earth

It is also possible to rotate your view of the Earth (change your heading and tilt), without changing your position.

Imagine turning your body left or right, or nodding your head up or down (these motions have the technical names yaw and pitch, respectively).

As with translational and orbital motion, there are three basic ways to rotate:

• Click-and-drag:

Hold down the Ctrl key (on Windows) or the Command key (on Macs) and click-and-drag the mouse to the left or right to rotate yourself left/clockwise or right/counter-clockwise, respectively (note: this is the opposite direction of orbiting).

Hold down the Ctrl key (on Windows) or the Command key (on Macs) and click-and-drag the mouse away from or towards you, to incline your view downward or upward, respectively.

• Navigation Controls:


 
Orbit/
Rotation
Controls

With the mouse, point at the upper right corner of the Display pane, whereupon the navigation controls will appear.

Point at the upper disk (with the eye), and click on the left or right side to turn your view clockwise or counter-clockwise, respectively (again changing your heading), or click on the upper or lower part of it to incline your view upward or downward (again changing your tilt).

As with the translation control, you can click and hold for continuous movement, and even slide around the edge to smoothly change orientations.

And again, the closer to the edge of the disk, the greater or faster the motion.

• Keyboard:

If necessary, click in the Display pane. Then use the arrow keys while holding down the Ctrl key (on Windows) or the Command key (on Macs):

		Ctrl ↑ Command ↑	incline upward
Ctrl ← Command ←	rotate left/clockwise	Ctrl↓ Command ↓	incline downward	Ctrl → Command →	rotate right/counter-clockwise

Note: the ADSW keys cannot be used here, since they are also used for menu selections.

To reiterate the difference between rotation and orbiting, in the former you will stay in one location while your view of the Earth will change, while in the latter you move around the fixed location at the center of the screen.

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Navigation Controls Summary

The following table summarizes the information above.

Note: The keyboard controls only function after you have clicked in the Display pane (they have different actions in the other panes).

Navigation Type		Mouse	Display	Keyboard
Zoom	In	Scroll Wheel Away		Page Up
	Out	Scroll Wheel Towards		Page Down
Move (Translate)	Left	Click-Drag Right		← A	For Slow Motion, also press: Win: Alt Mac: Opt
	Right	Click-Drag Left		→ D
	Forward	Click-Drag Towards		↑ W
	Backward	Click-Drag Away		↓ S
Fly To	Center & Zoom In	Double-Click
	Center & Zoom Out	Ctrl Double-click
Orbit a Location	Counter-Clockwise	Shift Click-Drag Left		Shift ← Shift A
	Clockwise	Shift Click-Drag Right		Shift → Shift D
	Forward/Upward	Shift Click-Drag Towards		Shift ↑ Shift W
	Backward/Downward	Shift Click-Drag Away		Shift ↓ Shift S
	To the North			N
	To the North and the Vertical			R
Rotate in Place (Yaw & Pitch)	Left/Clockwise	Windows: Ctrl Click-Drag Left Mac: Command Click-Drag Left		Win: Ctrl ← Mac: Command ←
	Right/Counter-Clockwise	Windows: Ctrl Click-Drag Right Mac: Command Click-Drag Right		Win: Ctrl → Mac: Command →
	Upward	Windows: Ctrl Click-Drag Towards Mac: Command Click-Drag Towards		Win: Ctrl ↑ Mac: Command ↑
	Downward	Windows: Ctrl Click-Drag Away Mac: Command Click-Drag Away		Win: Ctrl ↓ Mac: Command ↓

 

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Layers of Information

Google Earth can access a world of mapable knowledge, both its own data sets and information on the World-Wide Web that is georeferenced.

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The different types of information that Google Earth provides are organized together in layers that can be turned on and off as needed, by clicking on the checkboxes next to their names.

The layers Borders and Labels and Roads are the most generally useful, as they can help orient you.

The Gallery contains data from a number of primary sources such as NASA and the National Geographic, as well as a small selection of overlayed historical maps.

The Photos layer is interesting because it references large collections of photographs on the World-Wide Web that have been georeferenced (given a location in a standard format). Be aware, however, that these are generally not “peer-reviewed”.

Sometimes you may want to use others such as Places, 3D Buildings, and Weather. The former tends towards "advertised" establishments, though occasionally that is what you want to find.

The button Earth Gallery » will take you to a web page containing a gallery of featured content that you can download and open in Google Earth. Click on the button « Back to Google Earth to close this page.

Poke around a bit here to see what you can find of interest!

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Adding Your Own Content

Google Earth is customizable, allowing you to create your own collections of information.

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Creating Placemarks

You can often identify particular locations you are interested in from terrain, streets, buildings, or latitude and longitude.

You can save these locations for future reference with placemarks, which are indicated, by default, by yellow push-pins.

Placemarks also have a particular view of the Earth associated with them (distance, heading, and tilt), as shown in the picture at the right.

Any time you double-click on a placemark in the panes Display or Places, Google Earth will fly back to that location and provide that view.

Placemarks can have labels next to them, and when you click on them an information balloon will appear, providing your own descriptions and images.

 

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Organizing and Touring Placemarks

A group of associated placemarks can be organized by putting them together in their own folder, which can then be “toured” in a sequence.

If you first select a folder before creating new placemarks as described in Procedure 3, they will automatically be stored in this folder.

 

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Creating Paths

A collection of locations can be joined together into a path, which appears in the Display pane as a colored line.

Paths can represent travel routes, rivers, or other linear features.

They can connect the same locations as a set of placemarks, to show how they might be related to each other, e.g. by geography or time.

If you go to another location, and then double-click on a path in the Display or Places panes, Google Earth will fly back to it and show its extent.

Like placemarks, new paths are stored in the folder called My Places, which you can see listed in the pane Places.

Paths automatically have tours defined for them; simply click on the path and then on the button  Play Tour. You may find, however, that it is too slow, and that you’ll prefer a manual excursion over the path.

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Saving Placemarks and Paths

Please note that the folder My Places is stored on the local computer, so it’s very important, when you are finished, to save a copy of your work to your U: drive for use on other computers.

Simply menu File, then Save, and finally Save Place As; the resulting file is of the type .kml or compressed as .kmz . It can then be easily sent to others and read into Google Earth on another computer, though initially it will be placed in the folder Temporary Places.

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Decorating Content Descriptions

Google Earth is actually a special kind of web browser, and its descriptions are tiny web pages.

The information you put into your descriptions can be decorated with different font styles, images, movies, etc.

The format is HTML which can be easily created using the Amherst College web site or with Dreamweaver or even with Microsoft Word, and then copied and pasted into the description window.

You can also write the HTML directly if you want; there is a summary of the language at http://www.ats.amherst.edu/software/dhtml/1.html/.

Google provides some HTML templates to get started at http://earth.google.com/intl/en/outreach/tutorial_balloon.html.

As a specific example, you can embed an external image from the web directly into a placemark’s description as follows:

<img src="https://www.amherst.edu/media/view/3448/standard/jcwinterlarge.jpg"
     width="259" height="370" />

More generally, you can embed geotags into digital photographs, which (when placed on the web) will eventually show up on the Geographic Web layer of Google Earth; here’s a tutorial on how to do this with the free application Picassa: http://www.ogleearth.com/2006/06/picasa_google_e.html.

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Geographic Information Systems