Google Earth

Introduction

Google Earth is a free-of-charge, downloadable virtual globe program. It maps the entire

earth by pasting images obtained from satellite imagery, aerial photography and GIS over

a 3D globe. Most of us have been using one online mapping program or another for years

now. They're a godsend for those of us who get lost within a 3-mile radius of our homes,

and they're just plain fun for people who enjoy figuring out where stuff is. With this in

mind, imagine how amazing Google Earth must be for it to elicit awe from the online

community and cause South Korea to demand changes to the program.

The starting view in Google Earth

Google Earth is no ordinary mapping application. Type "Denver, CO" into the Google

Earth search box, and yes, you can learn where Denver is in relation to Grand Junction

and how to get from your address to 1600 Curtis St. in downtown Denver. In the same

search, though, you can also learn that 1600 Curtis St. is in the 80202 zip code and that

there are 12 Starbucks Coffee shops within a half-mile radius of that address; you can

zoom out from 1600 Curtis St. and watch it disappear into a satellite view of the Earth

and then zoom back in as if you were falling onto 1600 Curtis St. from space; and if you

click on "Forbidden City" in the "Sightseeing" column, you can see what it would look

like to fly Superman-style from 1600 Curtis St. in Denver to the Forbidden Palace in

Beijing, China.

And you thought the world was small before.

The application is fairly easy to use, but there are a lot of functions to try out. So let's see

how you can get started with Google Earth.

Overview

Formerly known as Earth Viewer, Google Earth was developed by Keyhole, Inc., a

company Google acquired in 2004. The product was renamed Google Earth in 2005 and

is currently available for use on personal computers running Microsoft Windows 2000 or

XP, Mac OS X 10.3.9 and above, and Linux (Released on June 12 of 2006). In addition

to releasing an updated Keyhole based client, Google also added the imagery from the

Earth database to their web based mapping software.

Many large cities are available in a resolution high enough to see individual buildings,

houses, and even cars. In cities such as London, Washington DC, and Seattle, individual

people can be clearly discerned. The degree of resolution available is based somewhat on

the points of interest, but all land is covered in at least 15 meters of resolution. [citation needed]

Cambridge, MA and Fulton County, NY have the highest resolution, at six inches.

Google Earth allows users to search for addresses (for the USA, Canada, and Europe

only), enter coordinates, or simply use the mouse to browse to a location.

What is Google Earth?

Google Earth is currently available for download as a desktop application, although you

need to be connected to the Internet to use it. Every time you open Google Earth, it

automatically connects to Google's servers, giving you access to terabytes of

geographical, political and social data. For instance, you can view a city with certain

"layers" turned on, including topographical information, population data and crime

statistics for the area. The layers and all of the map navigation buttons, including zoom,

tilt and rotate, are all located in the Google Earth frame.

Launch page with toolbars

The big deal right now is that the basic version of Google Earth is completely free, and

there aren't even any ads. Of course, this could change in the future. So let's all start by

downloading the free version of the software located at Earth.Google.com while it's still

free and unfettered by ads. If your computer runs Windows, Linux or Mac OS X 10.3.9

or higher, and it's fewer than five years old, you should have no problem meeting the

system requirements. If your computer can't run the application, read on to find out what

you'll be able to do once you update your equipment.

Once you open Google Earth and start moving around a bit, you'll immediately notice

one of the biggest "whoa" aspects of the program: Some of the information is 3-D, and

the stuff that isn't 3-D is still a photograph -- there are no illustrated maps here. The

baseline visual data comes from satellite imagery and aerial photographs taken by

aircraft.

While Google Earth comprises an array of features that would probably take months to

fully utilize, the basic features fit loosely into the following categories:

Mapping/directions

Local search

Sightseeing

We'll address each of these utilities in the following sections. But first, let's find out

where Google Earth gets its data.

3D Buildings

A montage illustrating some of Google Earth's capabilities

A feature implemented by Google after its acquisition of Keyhole is a 3D dataset for (as

of June 2006) 38 US cities.[1] This data is provided by Sanborn Citysets. This feature is

limited to displaying grey overlaying "blocky" buildings. On March 14, 2006, Google

acquired @Last Software, makers of SketchUp, who had created a plugin for 3D

renderings in Google Earth.

The cities currently included are only from the United States. However, 3D buildings are

available for certain buildings around the world using programs from other websites. The

cities include: New York City (Manhattan below Central Park and West Brooklyn),

Chicago (the Loop, near Magnificent Mile, and residential areas north, south, and just

west of those areas along the lake), Los Angeles (downtown, areas along the Miracle

Mile, Wilshire Blvd), Honolulu (downtown and along the beach), San Francisco (the

northeastern quadrant), Philadelphia (downtown and residential areas to the south and

west), Houston (downtown), Washington, Boston, Dallas, Minneapolis, Saint Paul,

Miami, Atlanta, Denver, Seattle, Detroit (downtown), Arlington, Baltimore, St. Louis

(downtown), Pittsburgh, Cleveland, San Diego, Long Beach, Sacramento, Cincinnati,

Tampa, Fort Lauderdale, New Orleans, Kansas City, Buffalo, Portland, Las Vegas, Jersey

City (along the Hudson River), Newark, Memphis, Phoenix, and St. Petersburg, Florida,

USA.

Specifications

Google Earth comes with atmosphere effects and seabed

Coordinate System

o Data is stored and presented using the standard WGS84 datum.

Baseline resolutions

o U.S.: 15 m

o Global: Generally 15 m (some areas such as certain oceanic islands are in

extremely low resolution).

Typical high resolutions

o U.S.: 1 m, 0.6 m, 0.3 m, 0.15 m (extremely rare; e.g. Cambridge, Ma. and

Google Campus)

o Global:

Altitude resolution:

o Surface:

o Seabed: Not applicable (a colorscale approximating seafloor depth is

"printed" on the spherical surface).

Age: Usually less than 3 years old. (For example, the image area around Taipei

101 shows the building before the red construction elevators were removed in

2004 and the new WAPA Path 15 power line is still under construction (also in

2004).)

Google Earth is unlikely to operate on older hardware configurations. The most recent

downloads available document these minimum configurations:

Pentium 3, 500 Mhz

128 MB RAM

400 MB free disk space

Network speed: 128 Kbit/sec

3D-capable graphics card with 16 MB of Video RAM

1024x768, "16-bit High Color" screen

The most likely mode of failure is insufficient video RAM: the software is designed to

declare failure if 32 MB of video RAM is not available. The next most likely mode of

failure is Internet access speed. Except for the very patient, broadband internet (Cable,

DSL, T1, etc.) is required. Again, resolution is not uniform, some towns such as St.

Petersburg are only partially available in high-resolution. Compare the resolution of these

older B&W data:

http://terraserver-usa.com/image.aspx?

T=1&S=10&Z=17&X=3284&Y=20743&W=1

versus what is currently available with Google Earth in color:

Maps and aerial photos Coordinates: 37.4738° -79.2263°

o WikiSatellite view at WikiMapia

o Street map from MapQuest or Google Local

o Topographic map from TopoZone

o Aerial image or topographic map from TerraServer-USA

o Satellite image from Google Maps or Microsoft Virtual Earth

In this case, the TerraServer-USA data can identify individual trees but its data is

structured in cumbersome tiles. As with much GIS data, the utility of the data is

application-dependent for the purpose of determining if resolution is sufficient. Also note

that from a usability point of view, TerraServer loses its center point when one zooms in

and out where Google Earth browsing is smooth; a clear benefit, but at the price of the

somewhat demanding requirements imposed upon the video card.

It is worth noting however, that with some work, images from TerraServer can be

integrated as Image Overlays into Google Earth, allowing the user to combine the higher

(in some cases) resolution imagery from TerraServer over the smoother Google Earth

program.

Mac OS X Version

Google Earth (Mac OS X)

A version for Mac OS X was released on January 10, 2006, and is available for download

from the Google Earth website. With a few exceptions noted below, the Mac version

appears to be stable and complete, with virtually all the same functionality as the original

Windows version.

Screenshots and an actual binary of the Mac version had been leaked to the internet a

month previously, on December 8, 2005. The leaked version was significantly

incomplete. Among other things, neither the Help menu nor its "Display License" feature

worked, a pretty sure sign that the version was intended for Google's internal use only.

Google released no statement regarding the leak.

Currently, the Mac version runs only under Mac OS X versions 10.4 and 10.3.9.

Currently, there are no "Plus" or "Pro" versions for the stable release. There is no

embedded browser and no direct interface to Gmail. There are a few bugs concerning the

menu bar when switching between applications. There are a few bugs concerning

annotation balloons and printing.

The latest version is 4.0.1694 released on July 17, 2006, is currently available as a beta

version and features amongst others a new user interface and the option for Mac OS X

users to upgrade to the "Plus" version.

Linux Version

Starting with the version 4 beta, Google Earth functions under Linux, it is a native port

and uses the Qt-toolkit. Google has taken the position that it will attempt to make Google

Earth compatible with all mainstream distributions

Google Earth 4(beta) Running on Ubuntu Linux 6.06

Minimum System Requirements:

Kernel: 2.4 or later

CPU: Pentium 3, 500 MHz

System Memory (RAM): 128 MB

Hard Disk: 400 MB free space

Network Speed: 128 kbit/s

Screen: 1024x768, 16 bit color

Tested and works on the following OSs:

o Ubuntu 5.10/6.06

o Suse 10.1

o Fedora Core 4/5

o Linspire 5.1

o Gentoo 2006.0

o Debian 3.1

o Red Hat 9

o Slackware 10.2

o FreeBSD 6.1/7.0 with Linux Emulation

Accuracy

The west side of Gibraltar, tilted view showing the sea rising up Gibraltar Rock - claimed

height of the sea just off the beach at Elliots Memorial, 252 m.

Google Earth shows that the length of equator is 40,030,236.42 metres.

Most land areas are covered in satellite imagery with a resolution of about 15m per pixel,

and some population centers are also covered in aircraft imagery (orthophotography) of

several pixels per meter. Oceans are covered in much lower resolution.

Due to the limited spatial resolution of the altitude map, altitudes are often inaccurate,

especially the altitude of small features, like mountain tops; e.g. Mount Everest's height is

short by 253m, and the sea near Gibraltar is shown with an altitude of 252m.

Unlike the satellite images, the orthophotography has a perspective from close to the

surface, leading to distortions when used in a mosaic. Tall buildings sometimes appear to

be leaning towards each other (conspicuous in e.g. near the Empire State building in New

York City). The Fatih Sultan Mehmet Bridge on the Bosporus may be another example of

this effect. However, this effect is inevitable with any source of aerial photography, and

is present in Getmapping's imagery of England and Wales, and the providers of much of

the detailed photography have processed the images so that the joins are as seamless as

possible.

Google has resolved many inaccuracies in the vector mapping since the original public

release of the software, without requiring an update to the program itself. An example of

this was the absence of the Nunavut territory in Canada, an area comparable in size to

Western Europe.[citation needed] Google Earth's map boundaries of Northern Canada showed

only the Northwest Territories, not the division of Nunavut created on April 1, 1999. This

inaccuracy was corrected by one of the data updates in early 2006. Recent updates have

also increased the coverage of detailed aerial photography, particularly in western

Europe. Yet aeroplanes that were in flight as the pictures were taken are clearly visible - a

prime example being a plane flying over the Devil's Punch Bowl, Hindhead, Surrey, UK

that dramatically blocks the view.

Many of the images also appear to be out of date. For example, based on the scale of new

development, Milton Keynes in the UK is at least six years out of date. New applications,

such as ViewGL, were developed to address this situation.

Errors sometimes occur due to the technology used to measure how tall terrain is to

create the effect of mountains in 3D, such as tall buildings in Adelaide being mistaken for

a small mountain, instead of being rendered flat like it should be.

Place name and road detail vary greatly from place to place, and are most accurate in the

USA and Europe, although regular mapping updates tend to improve this. Also, the North

and South Poles are marked as 89°59'60" N and 89°59'60" S respectively, rather than the

correct 90°00'00" N and 90°00'00" S.

The images are not all taken at the same time, but are generally current to within three

years. Image sets are sometimes not correctly stitched together. Updates to the

photographic database can occasionally be noticed when placemarks appear to shift

unexpectedly across the earth's surface. Though the placemarks have not in fact moved,

the imagery is composed and stitched differently. Such an update to London's

photography in early 2006 created shifts of 15-20 metres in many areas, noticeable

because the resolution is so high.

The "Measure" function shows that the length of equator is about 40,030.24 km, giving

an error of −0.112% compared with the actual value of 40,075.02 km; for the meridional

circumference, it shows a length of about 39,963.13 km, also giving an error of −0.112%

compared with the actual value of 40,007.86 km.

The stars in the background are not random. Google Earth uses a real star map to render

the background.

Criticisms

US bias

The software, in particular the search engine, is criticised for its US-bias; for example,

entering in searches for "Birmingham" and for "St. Petersburg" bring up US cities, as

opposed to the original and larger cities of those names (in the UK and Russia

respectively). Fortunately, in Google Earth 4 (beta), more major cities can be found

without typing in the country name (eI: Melbourne, Singapore, Shanghai, Cairo, Cape

Town, Cologne (Köln), Lima, and Jerusalem). Still, some places outside of the US can't

be found with the search function unless the country name is added and written out in full

(except for "UK" and "MX"), while you can simply abbreviate states for US locations.

The default setting is to U.S. customary units, despite metric units being the international

standard officially adopted by every nation but three (the U.S, Liberia, and Myanmar,

although Liberia and Myanmar use metric in practice). Critics assert that while the units

can be changed, they should be set to metric by default, as well as pointing out that the

3D buildings feature is also limited at present to major US cities. Others counter that, as

an American creation by a predominantly US-based corporation, it is Google's right to

give preference to that country. Additionally, Google Earth has recently had their largest

update of earth imagery, making at least 33% of land covered by satellite images.

Google has also admitted problems with the software on systems using non-ASCII

characters, for example, Chinese or Japanese.

Naming disputes

Some South Korean users have been angered by the fact that Google Earth and Google

Maps use Japanese names for bays along the southeastern coast of the Korean

Peninsula.Examples include bays near Busan (labelled Nakutogu Po and Kanrai ho),

Masan (labelled Masan Ko, Kisan-ko, and Unchen Wan), and Goseong (labelled Kojo-

wan, Toto wan, Nan Wan, and Toei kawan).

The software was criticized by Taiwanese users because the island was labelled as a

province of mainland China. This has since been changed, but the change has angered the

People's Republic of China.

Google Earth confuses towns in Poland and Germany: Jelenia Gora in Poland is

incorrectly referred to as Hirschberg, whereas Görlitz on the west side of the border is

called Zgorzelec, the name of its Polish neighbour.

Google Earth, under "alternate place names," includes "Jerusalem" and "Yerushalayim"

but does not include the Arabic name for the city, "Al Quds".

National security and privacy issues

The U.S. Vice President's residence as seen through Google Maps.

The software has been criticised by a number of groups, including national officials, as

being an invasion of privacy and even posing a threat to national security. The typical

argument is that the software provides information about military or other critical

installations that could be used by terrorists. The following is a selection of such

concerns:

The Indian president APJ Abdul Kalam has expressed concern over the

availability of high-resolution pictures of sensitive locations in India.

The South Korean government has expressed concern that the software offers

images of the presidential palace and various military installations that could

possibly be used by their hostile neighbour North Korea.

The 2006 incidental finding of a large topographical replica in the remote

Huangyangtan region of China, purportedly a small-scale recreation of the

Karakoram mountain range currently under Indian control. When it was

confirmed that the territory modelled corresponded to a politically disputed

borderline between the neighboring nations, spectators began to entertain sinister

military implications.

Operators of the Lucas Heights nuclear reactor in Sydney, Australia asked Google

to censor high resolution pictures of the facility.However, they later withdrew the

request.

Additionally some citizens, particularly the rich or famous, as well as victims or

perpetrators of crime, may have concerns over aerial information depicting their

properties and residences being diseminated freely. As relatively few jurisdictions

actually guarantee the individual's right to privacy, as opposed to the state's right to

secrecy, this is an evolving, but minor, point. Perhaps aware of these critiques, for a time,

Google had Area 51 (which is highly visible and easy to find) in Nevada as a default

placemark when Google Earth is first installed.

As a result of pressure from the United States government, the residence of the Vice

President at Number One Observatory Circle is obscured through pixelization in Google

Earth and Google Maps.

Google Earth Community

The Google Earth Community is an online forum which is dedicated to produce

placemarks of interesting or educational perspectives. It may be found on the Google

Earth webpage or under the Help section on the program itself. After downloading a

placemark, it will automatically run Google Earth (if not opened), and fly to the area

specified by the person who placed it. Once there, you can add it to your "My Places" by

right clicking on the icon and selecting "Save to My Places". Additionally, anyone can

post a placemark for others to download; as long as you have an account.

Google Earth Plus

Google Earth can be upgraded to a "Plus" edition for $20. Google Earth Plus is an

individual-oriented paid subscription upgrade to Google Earth and adds the following

features:

GPS integration – read tracks and waypoints from a GPS device. 3rd party

applications have been created which provide this functionality using the basic

version of Google Earth by generating KML files based on user-specified

waypoints. However, these tools only work with specific GPS devices whereas

Google Earth Plus provides support for the Magellan and Garmin product lines,

who together hold a large share of the GPS market.

Higher resolution printing.

Customer support via email.

Annotation – adds draw/sketch tools for richer annotations (can be shared as

KML).

Data importer – read address points from CSV files.

Google Earth Pro

Google Earth Pro is a business-oriented paid upgrade to Google Earth that has more

features than the "Plus" version and costs $400 to purchase. The Pro version is capable of

running additional add-on software.

Google Earth Data

Google Earth was once a premium program called Keyhole that cost about $90. When

Google purchased Keyhole, it inherited terabytes of digital mapping data and set about

creating a basic version of the software that would be available for free download. Now

you're all caught up.

Mount St. Helens, Washington State, USA

The photographic maps available on Google Earth come primarily from two sources:

satellites and aircraft. Google gets this imagery and other digital mapping information

from sources such as TeleAtlas and EarthSat, both of which compile photographs and

maps into digital form for commercial applications. Because the data comes from

different sources, it's provided at different resolutions, which is why some areas of the

globe appear crisp even at street level while others are blurry from a great distance. When

you use Google Earth, you are not viewing the imagery in real-time: According to

Google, the information is no more than three years old and is continually updated as new

data becomes available.

Google Earth has the United States, Canada and the United Kingdom covered to street

level, meaning you can zoom in and view road names and local businesses and get

directions from here to there. The database has a good amount of information on Western

Europe, as well, but the rest of the world is hit or miss. While you can zoom in and get a

pretty good look at the Egyptian pyramids, you can't see street names or find a grocery

store in the area.

This brings us to another source of Google Earth's data: the Google search engine. Part of

what makes Google Earth so addictive is its collaboration with Google search. When

you're viewing a city, you can search for coffee shops, restaurants, grocery stores, bars

and tons of other businesses in the vicinity, and you can click on them to get detailed

information from the Google search engine. Users can also add a business location to a

map by clicking on "Add/Edit a Business Listing" in the Google Earth toolbar.

Now let's get back to playing with Google Earth. In the next section, we'll start with the

basic functions.

Conclusion

Google Earth is a free-of-charge, downloadable virtual globe program. It maps the entire

earth by pasting images obtained from satellite imagery, aerial photography and GIS over

a 3D globe. Most of us have been using one online mapping program or another for years

now. Google Earth is no ordinary mapping application. Google Earth is currently

available for download as a desktop application, although you need to be connected to the

Internet to use it. Every time you open Google Earth, it automatically connects to

Google's servers, giving you access to terabytes of geographical, political and social data.

Bibliography

Sites:

1) www.earth.google.com

2) www.digg.com

3) www.nature.com