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Google Earth is a free-of-charge, downloadable virtual globe program. It maps the earth by superimposing images obtained from satellite imagery, aerial photography and GIS over a 3D globe.
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, 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. 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. Las Vegas, NV, 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. Google Earth also has digital terrain model 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. 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 available in a free version, and in licensed versions for commercial use. See also Keyhole Markup Language (KML). Using Google Earth Google Earth is designed for complete ease and efficiency. It has a short tutorial on how to use it and a control panel below the main window. Zooming As well as the control panel, Google Earth can be operated using the mouse and keyboard. Double clicking on a location causes the camera to zoom in on the spot. The mouse roller can also be used for zooming in and out and the plus and minus keys work as well on some versions. Moving The viewing window can be moved left, right, up and down as well as diagonal by clicking a location with the mouse and the moving the cursor in the opposite direction to that in which you want to go (intuitively, grabbing hold of the view and dragging it under you). If you drag and release the mouse while the view is moving, the view will continue moving until stopped. A simpler way to move is to click both sides of the mouse at once at any spot on the screen, and (depending on how far you are from the center of the viewpoint) you will move at that certain speed. The arrow keys also allow you to move. The left key moves left, the right key moves right and so on. However, Using the keyboard does not move you as quickly as the mouse does. The final way of moving is to search for a location or post code in the search box in the top left corner or clicking on one of the pre-set locations. Panning Google earth also allows you to move higher and lower and to rotate the camera. This can be done by clicking and dragging with the right mouse button or using the <, >, pg. up and pg. down keys. Global search The box in the top left of the screen allows you to search for any location on earth quickly and pain free, just type in the place you want to see and press play to have the camera go straight there. For a more precise search, type in the place followed by its approximate location i.e. Las Vegas, USA Local search Google Earth also allows you to search your local area for something, eg a dentist. NB It may require confirmation of the area you want to search. If so, enter a postcode. 3D buildings
Specifications Google Earth is unlikely to operate on older hardware configurations. The most recent downloads available document these minimum configurations: 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. 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 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 and a few bugs concerning annotation balloons and printing. The latest version, 4.0.1694, released on July 17, 2006, is currently available as a beta version and features, among other things, a new user interface and the option for Mac OS X users to upgrade to the "Plus" version. *. However many users have reported difficulties with Google Earth crashing in the latest version when zooming in. * Linux version Starting with the version 4 beta, Google Earth functions under Linux, as a native port using the Qt-toolkit. Minimum System Requirements * Level of accuracy
Inaccuracies 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 orthophotos have a perspective from close to the surface, leading to distortions when used in a mosaic. For example, tall buildings sometimes appear to be leaning toward each other (this is conspicuous, for example, near the Empire State building in New York City, and the Fatih Sultan Mehmet Bridge on the Bosporus may show another example of this effect). This effect is inevitable with any aerial photography (it is also present in Getmapping's imagery of England and Wales, for example); the providers of much of Google Earth's detailed photography have processed the images so that the joins are as seamless as possible. Another problem with orthophotos is that airplanes in flight have been captured by the cameras, blocking the view of areas beneath them: an example is a plane flying over the Devil's Punch Bowl, Hindhead, Surrey, UK. 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 have been developed to address this situation, but only cover the USA. Also, some newer versions of the program appear to contain images that are older than images in older versions of the program. For example, a building in Aberdeen, Scotland, which was built in 2002 and which was clearly visible in a 2005 version of Google Earth, had disappeared in a 2006 version which showed the original (demolished) building instead. 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. 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 "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. 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 older and larger cities with similar names (Birmingham, UK and St. Petersburg, Russia respectively). However in Google Earth 4 (beta), more major cities can be found without typing in the country name (eg: 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. 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 and Japanese 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 National security and privacy issues
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. Copyright Currently, many consider that every Google Earth image is a copyrighted map. It is made with copyrighted code and data which may not be used as part of another work. However, the output of Google Earth is very similar to that of programs such as Microsoft Flight Simulator and The Sims, which are also made from copyrighted code and data. Such images are considered freely available for use in another project, or as an original work. By contrast, many articles use images created with NASA's globe software World Wind using Blue Marble, Landsat or USGS layer, each of which is in public domain. Such images are understood to be in the public domain because they are screenshots. Lotus Development corporation had sued Mosaic Software and Paperback software because their command structure and screen output was similar to 1-2-3, however the successful judgements in favor of Lotus were overturned when a judge ruled in favor of Borland's Quattro that only the underlying code was protected by copyright. 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: 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 and advanced printing modules. These used to cost extra in addition to the $400 fee but have recently been included free in the package. * See also Community and placemarks Unofficial guides and tips Add-ons Games Tools Reviews | |||||||||||||||||||||||||||||||
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