Google Earth
Maintainer: Google
Stable release: 4.1.7087.5048 (Win) / 4.1.7076.4558 (Mac) / 4.1.7076.4458
(Linux) (May 24, 2007 (Win) / May 9, 2007 (Mac) / May 6, 2007 (Linux)) [+/-]
Preview release: N/A [+/-]
OS: Windows 2000, XP & Vista, Mac OS X, Linux
Available language(s): Multilingual[1]
Use: Virtual globe
License: Proprietary
Website: Google Earth
Google Earth is a virtual globe program that was originally called Earth
Viewer and was created by Keyhole, Inc. It maps the earth by the
superimposition of images obtained from satellite imagery, aerial
photography and GIS 3D globe. It is available under three different
licenses: Google Earth, a free version with limited functionality; Google
Earth Plus, which includes a few more features; and Google Earth Pro,
intended for commercial use.[2]
Overview
Formerly known as Earth Viewer, Google Earth was developed by Keyhole, Inc.,
a company acquired by Google in 2004. The product was renamed Google Earth
in 2005 and is currently available for use on personal computers running
Microsoft Windows 2000, XP, or Vista; Mac OS X 10.3.9 and above; Linux
(released on June 12, 2006); and FreeBSD. In addition to releasing an
updated Keyhole based client, Google also added the imagery from the Earth
database to their web based mapping software.
The viewer will show houses, the color of cars, and even the shadows of
people and street signs.
The degree of resolution available is based somewhat on the points of
interest, but most land (except for some islands) is covered in at least 15
meters of resolution[3]. Las Vegas, Nevada and Cambridge, Massachusetts
include examples of the highest resolution, at 15 cm (6 inches). Google
Earth allows users to search for addresses (for some countries only), enter
coordinates, or simply use the mouse to browse to a location.
Google Earth also has digital elevation model (DEM) data collected by NASA's
Shuttle Radar Topography Mission. This means one can view the Grand Canyon
or Mount Everest in three dimensions, instead of 2D like other map
programs/sites. Since 23 November 2006, the 3D views of many mountains,
including Mount Everest, have been improved by the use of supplementary DEM
data to fill the gaps in SRTM coverage[4]. In addition, Google has provided
a layer allowing one to see 3D buildings for many major cities in the US and
Japan.
Many people using the applications are adding their own data and making them
available through various sources, such as the BBS or blogs mentioned in the
link section below. Google Earth is able to show all kinds of images
overlaid on the surface of the earth and is also Web Map Service client.
Google Earth supports managing three-dimensional geospatial data through
Keyhole Markup Language (KML). It is available in a free version, and in
licensed versions for commercial use.
Google Earth has the capability to show 3D buildings and structures (such as
bridges), which consist of users' submissions using SketchUp, a 3D modeling
program. In prior versions of Google Earth (before Version 4), 3D buildings
were limited to a few cities, and had poorer rendering with no textures.
Many buildings and structures from around the world now have detailed 3D
structures; including (but not limited to): U.S., Canada, India, Japan,
United Kingdom,[5] Germany, Pakistan, Amsterdam and Alexandria[6].
Three-dimensional renderings are available for certain buildings and
structures around the world via Google's 3D Warehouse[7] and other websites.
Wikipedia and Panoramio integration
In December 2006 Google Earth added a new layer called "Geographic Web" that
includes integration with Wikipedia and Panoramio. In Wikipedia, entries are
scraped for coordinates via the Coor dms series of templates. If the options
to show Wikipedia or Panoramio entries are selected, users will be presented
with clickable dots in their current Google Earth view. When any of these
dots are selected, the user will be shown the Wikipedia or Panoramio entry
right in Google Earth. There is also a community-layer from the project
Wikipedia-World. More coordinates are used, different types are in the
display and different languages are supported than the built-in Wikipedia
layer. See: *dynamic resp. static layer. Google announced on May 30th, 2007
that it is acquiring Panoramio.
Specifications
* Coordinate System and Projection
o The internal coordinate system of Google Earth is geographic coordinates
(latitude/longitude) on the World Geodetic System of 1984 (WGS84) datum.
o Google Earth shows the earth as it looks from an elevated platform such as
an airplane or orbiting satellite. The projection used to achieve this
effect is called the General Perspective. This is similar to the
Orthographic projection, except that the point of perspective is a finite
(near earth) distance rather than an infinite (deep space) distance.[8]
* Baseline resolutions
o U.S.: 15 m (some states are completely in 1 m or better)
o Germany, Switzerland, Netherlands, Denmark, England, Andorra, Luxembourg,
Liechtenstein, San Marino, Vatican City: 1 m or better
o Global: Generally 15 m (some areas, such as Antarctica, are in extremely
low resolution), but this depends on the quality of the satellite/aerial
photograph uploaded.
* Typical high resolutions
o U.S.: 1 m, 0.6 m, 0.3 m, 0.15 m (extremely rare; e.g. Cambridge and Google
Campus, or Glendale)
o Europe : 0.3 m, 0.15 m (e.g. Berlin, Zürich, Hamburg)
* Altitude resolution:
o Surface: varies by country
o Seabed: Not applicable (a colorscale approximating sea floor depth is
"printed" on the spherical surface).
* Age: Usually less than 3 years old. The date next to copyright information
is often cited as the date the picture was taken, but it is not true
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 kb/s
* 16MB 3D-capable graphics card
* 1024x768, "16-bit High Color" screen
* Windows XP or Windows 2000 (not Windows ME compatible), Linux, Mac OS X
The most likely mode of failure is insufficient video RAM: the software is
designed to warn the user if their graphics card is not able to support
Earth (this often occurs due to insufficient Video RAM or buggy graphics
card drivers). The next most likely mode of failure is Internet access
speed. Except for the very patient, broadband Internet (Cable, DSL, T1,
etc.) is required.
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, indicating that this 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. There is no embedded browser and no direct interface to Gmail. There
are a few bugs concerning the menu bar when switching between applications
and a few bugs concerning annotation balloons and printing.
The latest version, 4.1.7076.4558, released on May 9, 2007, features, among
other things, a new user interface and the option for Mac OS X users to
upgrade to the "Plus" version.[9] Some users reported difficulties with
Google Earth crashing in the latest version when zooming in.[10]
Linux version
Starting with the version 4 beta, Google Earth functions under Linux, as a
native port using the Qt-toolkit.
Minimum System Requirements[11]
* 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 distributions:
* Ubuntu 5.10/6.06/6.10/7.04
* SUSE 10.1/10.2
* Fedora Core 4/5/6/7
* Linspire 5.1
* Gentoo 2006.0
* Debian 3.1/4
* Red Hat 9
* Slackware 11.0
* FreeBSD 6.1/7.0 with Linux Emulation
* Arch Linux 0.7.2 Duke
* Xandros 3.0.3 Business Edition
* Mandriva 2007
* Sabayon Linux 3.26
* PCLinuxOS 5.0
Resolution and accuracy
Most land areas are covered in satellite imagery with a resolution of about
15 m per pixel. Some population centers are also covered by aircraft imagery
(orthophotography) with several pixels per meter. Oceans are covered at a
much lower resolution, as are a number of islands; most notably, Tórshavn,
the capital of the Faroe Islands, and the Isles of Scilly off southwest
England, are at a resolution of about 500 m or less. These pictures are
provided by Terrametrics. The majority of East Anglia in the UK, with the
exception of a few cities and other sites, also has a very low resolution.
Place name and road detail vary greatly from place to place. They are most
accurate in the USA and Europe, but regular mapping updates are improving
coverage elsewhere.
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 from Google Earth's map
boundaries of the Nunavut territory in Canada, a territory that had been
created on April 1, 1999; this mistake 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.
Cloud cover and shadows can make it difficult or impossible to see details
in some land areas, including the shadow side of mountains.
The stars in the background are not random. Google Earth uses a real star
map to render the background. [verification needed]
Inaccuracies
Google Earth is a complex application representing two and three dimensional
data, vector data, integer and real numbers, and a variety of geometric
projections. The imagery comes from a variety of sources and the processing
of the imagery is done both by machine and humans. In addition, there are
many terabytes of information from a variety of sources involving many
people. As a result, there are bound to be inaccuracies in the data. Google
is continuously taking input and improving the existing data.
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 drastic changes take place in the appearance of the landscape, like for
example Google Earth's incomplete updates of New Orleans following Hurricane
Katrina, or 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.
Errors sometimes occur due to the technology used to measure the height of
terrain; for example, tall buildings in Adelaide cause one part of the city
to be rendered as a small mountain, when it is in fact flat. The height of
the Eiffel Tower creates a similar effect in the rendering of Paris.
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 Earth; 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 Arctic polar ice caps are completely absent from the current version of
Google Earth. Information explaining this notable absence is difficult to
find if any has been supplied at all. Google Earth presently renders no ice
packs in the arctic circle, and the geographic North Pole is found hovering
over the Arctic Ocean. There is very low resolution coverage of the
Antarctic continent (1m resolution images of some parts of Antarctica were
added in June 2007 for the first time). The tiling system produces bizarre
artifacts near the poles as the tiles become 'infinitely' small and rounding
errors accumulate.
The atmosphere in Google Earth is greatly exaggerated. Comparisons with
actual photographs show the Google Earth atmosphere to be 20 times thicker.
Where no 3 arc second digital elevation data was available, the three
dimensional images covering some areas of high relief are not at all
accurate, but most mountain areas are now well mapped. The underlying
digital elevation model has been placed 3 arc seconds too far north and up
to 3 arc seconds too far west. This means that some steep mountain ridges
incorrectly appear to have shadows extending over onto their south facing
sides. Some high resolution images have also been misplaced, an example is
the image covering Annapurna, which is misplaced by about 12 arc seconds.
National security and privacy issues
The software has been criticized by a number of special 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.[12] Google subsequently agreed to censor such sites.[13]
* The Indian Space Research Organisation has said Google Earth poses a
security threat to India, and seeks dialogue with Google officials.[14]
* 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 neighbor North Korea.[15]
* In 2006, one user spotted a large topographical replica in a remote region
of China. The model is a small-scale (1/500) version of the Karakoram
Mountain Range, currently under the control of China but claimed by India.
When later confirmed as a replica of this region, spectators began
entertaining sinister military implications.[16][17]
* Morocco's main Internet provider Maroc Telecom has been blocking Google
Earth[18] since August 2006 without giving any justification for it.
* Operators of the Lucas Heights nuclear reactor in Sydney, New South Wales
asked Google to censor high resolution pictures of the facility.[19]
However, they later withdrew the request.[20]
* In July 2007, it was reported that a new Chinese navy Jin-class nuclear
ballistic missile submarine was photographed at the Xiaopingdao Submarine
Base south of Dalian[21].
Some citizens may express concerns over aerial information depicting their
properties and residences being disseminated 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. The usefulness of this
downgrade is questionable, as high-resolution photos and aerial surveys of
the property are readily available on the Internet elsewhere.[22] Capitol
Hill used to also be pixelized in this way but this was lifted.
Critics have expressed concern over the willingness of Google to cripple
their dataset to cater to special interests, believing that intentionally
obscuring any land goes against its stated goal of letting the user "point
and zoom to any place on the planet that you want to explore".
Google Earth Community
The Google Earth Community is an online forum[23] which is dedicated to
producing 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 also can be used to locate "disasters". Currently a user can
find these items within the google earth community. An example is a capsized
ship off of the shore (69°15′32.22″N 33°14′17.11″E / 69.25895, 33.2380861)
or a burning car, on A3 autobahn near Gieslenberg, N of Leverkusen, Germany
(51°4′47.04″N 6°59′17.77″E / 51.0797333, 6.9882694).
Copyright
Currently, every image created from Google Earth using satellite data
provided by Google Earth is a copyrighted map. Any derivative from Google
Earth is made from copyrighted data which, under United States Copyright
Law, may not be used except under the licenses Google provides. Google
allows non-commercial personal use of the images (e.g. on a personal website
or blog) as long as copyrights and attributions are preserved[24]. By
contrast, images created with NASA's globe software World Wind using Blue
Marble, Landsat or USGS layer, each of which is a terrain layer in the
public domain. Works created by an agency of the United States government
are public domain at the moment of creation. This means that those images
can be freely modified, re-distributed and used for commercial purposes.
Google Earth Plus
Google Earth can be upgraded to a "Plus" edition for a $20 annual
subscription fee. 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. Third 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.[25] 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. In
addition to this, as of late May 2007, the Linux version of the Google Earth
Plus application does not include any GPS functionality. This is not
mentioned anywhere on the product presentation, FAQ and help pages online
and a customer only gets to realize this after purchasing the application.
* Higher resolution printing.
* Customer support via email.
* Data importer: read address points from CSV files; limited to 100
points/addresses. A feature allowing path and polygon annotations, which can
be exported to KML, was formerly only available to Plus users, but was made
free in version 4.0.2416.
* Higher data download speeds
Many of Google Earth Plus's features can be added on for free with
third-party software and utilities[26], including GPS, spreadsheet import,
and geocoding.
Google Earth Pro
For a $400 annual subscription fee, Google Earth Pro is a business-oriented
upgrade to Google Earth that has more features than the "Plus" version. The
Pro version includes add-on software such as:
* Movie making.
* GIS data importer.
* Advanced printing modules.
These used to cost extra in addition to the $400 fee but have recently been
included in the package.[27]
Influences
The Google Earth interface bears a noted similarity to the ‘Earth’ program
described in Neal Stephenson’s sci-fi classic Snow Crash. Indeed, a Google
Earth co-founder claimed that Google Earth was modeled after Snow Crash,
while another co-founder said it was inspired by Powers of Ten.[28]
Other providers
* DigitalGlobe — the provider of high resolution imagery to Google Earth
* EarthSat
* Microsoft:
o Microsoft MapPoint
o TerraServer-USA
o Windows Live Maps
* NASA World Wind
* Pictometry
* ViewGL - updated aerial imagery for Google Earth
* WikiMapia
* PointAsia.com - A Virtual Earth Application covering 100% of Thailand
References
1. ^ Available in English,swahili, French, German, Spanish, Italiano and
Japanese
2. ^ Google Earth Product Comparison. Retrieved on 2007-01-07.
3. ^ Google Earth Coverage: Maps showing a visual representation of Google
Earth coverage
4. ^ Google Earth Community
5. ^ http://www.skyscrapernews.com/googleearth.php
6. ^ http://www.infopot.tk
7. ^ http://sketchup.google.com/3dwarehouse/
8. ^ http://www1.webng.com/azimuthal/earth_proj.html
9. ^ [1]
10. ^ [2]
11. ^ http://earth.google.com/download-earth.html
12. ^ "Kalam Concerned Over Google Earth". Retrieved on 2007-01-25.
13. ^ "Google Earth agrees to blur pix of key Indian sites".
14. ^ "Google Earth Poses Security Threat to India, ISRO Chief seeks
Dialogue". Retrieved on 2007-01-25.
15. ^ "Google Earth images compromise secret installations in S. Korea".
Retrieved on 2007-01-25.
16. ^ "Chinese X-file excites spotters". Retrieved on 2007-01-25.
17. ^ "From sky, see how China builds model of Indian border 2400 km away".
Retrieved on 2007-01-25.
18. ^ Message au monde - Message to the world
19. ^ "Google Earth prompts security fears". Retrieved on 2007-01-25.
20. ^ " Aussie Nuclear Reactor on Google Earth". Retrieved on 2007-01-25.
21. ^ "New Chinese Ballistic Missile Submarine Spotted". Retrieved on
2007-07-10.
22. ^ [3]
23. ^ [4]
24. ^ Google Earth Help Center: Can I post images to the web?
25. ^ [5]
26. ^ http://freegeographytools.com/?p=25
27. ^ [6]
28. ^ Avi Bar-Ze’ev (from Keyhole, the precursor to Google Earth) on origin
of Google Earth
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