Google Earth
Google Earth is a web and computer program created by Google that renders a 3D representation of Earth based primarily on satellite imagery. The program maps the Earth by superimposing satellite images, aerial photography, and GIS data onto a 3D globe, allowing users to see cities and landscapes from various angles. Users can explore the globe by entering addresses and coordinates, or by using a keyboard or mouse. The program can also be downloaded on a smartphone or tablet, using a touch screen or stylus to navigate. Users may use the program to add their own data using Keyhole Markup Language and upload them through various sources, such as forums or blogs. Google Earth is able to show various kinds of images overlaid on the surface of the Earth and is also a Web Map Service client. In 2019, Google revealed that Google Earth covers more than 97 percent of the world.
In addition to Earth navigation, Google Earth provides a series of other tools through the desktop application, including a measure distance tool. Additional globes for the Moon and Mars are available, as well as a tool for viewing the night sky. A flight simulator game is also included. Other features allow users to view photos from various places uploaded to Panoramio, information provided by Wikipedia on some locations, and Street View imagery. The web-based version of Google Earth also includes Voyager, a feature that periodically adds in-program tours, often presented by scientists and documentarians.
Google Earth has been viewed by some as a threat to privacy and national security, leading to the program being banned in multiple countries. Some countries have requested that certain areas be obscured in Google's satellite images, usually areas containing military facilities.
History
The core technology behind Google Earth was originally developed at Intrinsic Graphics in the late 1990s. At the time, the company was developing 3D gaming software libraries. As a demo of their 3D software, they created a spinning globe that could be zoomed into, similar to the Powers of Ten film. The demo was popular, but the board of Intrinsic wanted to remain focused on gaming, so in 1999, they created Keyhole, Inc., headed by John Hanke. Keyhole then developed a way to stream large databases of mapping data over the internet to client software, a key part of the technology, and acquired patchworks of mapping data from governments and other sources. The product, called "Keyhole EarthViewer", was sold on CDs for use in fields such as real estate, urban planning, defense, and intelligence; users paid a yearly fee for the service. Despite making several capital deals with Nvidia and Sony, the small company was struggling to pay and retain employees.Fortunes for the company changed in early 2003 during the 2003 invasion of Iraq, when Dave Lorenzini enticed CNN, ABC, CBS and other major news networks to use their sophisticated 3D flyby imagery to illustrate Baghdad activities for viewers, in exchange for on-air attribution. During the invasion, It was used extensively by Miles O'Brien and other on-air broadcasters, allowing CNN and millions of viewers to follow the progress of the war in a way that had never been seen before. Public interest in the software exploded and Keyhole servers were not able to keep up with demand. Keyhole was soon contacted by the Central Intelligence Agency's venture capital firm, In-Q-Tel, and the National Geospatial-Intelligence Agency, for use with defense mapping databases, which gave Keyhole a much-needed cash infusion. Intrinsic Graphics was sold in 2003 to Vicarious Visions after its gaming libraries did not sell well, and its core group of engineers and management including Brian McClendon and Michael Jones transitioned to Keyhole with Hanke remaining at the head.
At the time, Google was finding that over 25% of its searches were of a geospatial character, including searches for maps and directions. In October 2004, Google acquired Keyhole as part of a strategy to better serve its users. Keyhole's Earth Viewer was the foundation for what became Google Earth in 2005 while other aspects of its core technology were integrated into Google Maps.
In 2021, Google replaced its layers feature with a new one on its Google Earth software. This replacement consolidated some layers, but also removed some layers and features.
Imagery
Google Earth's imagery is displayed on a digital globe, which displays the planet's surface using a single composited image from a far distance. After zooming in far enough, the imagery transitions into different imagery of the same area with finer detail, which varies in date and time from one area to the next. The imagery is retrieved from satellites or aircraft. Before the launch of NASA and the USGS's Landsat 8 satellite, Google relied partially on imagery from Landsat 7, which suffered from a hardware malfunction that left diagonal gaps in images. In 2013, Google used datamining to remedy the issue, providing what was described as a successor to the Blue Marble image of Earth, with a single large image of the entire planet. This was achieved by combining multiple sets of imagery taken from Landsat 7 to eliminate clouds and diagonal gaps, creating a single "mosaic" image. Google has since used myriad sources to provide imagery in a higher quality and with greater frequency. Imagery is hosted on Google's servers, which are contacted by the application when opened, requiring an Internet connection.Imagery resolution ranges from except for the ocean floor, which ranges from. For much of the Earth, Google Earth uses digital elevation model data collected by NASA's Shuttle Radar Topography Mission. This creates the impression of three-dimensional terrain, even where the imagery is only two-dimensional.
Google asserts that 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 data that Google claims copyright under United States Copyright Law. Google grants license to this data allowing, among other things, non-commercial personal use of the images as long as copyrights and attributions are preserved. By contrast, images created with NASA's globe software WorldWind use The Blue Marble, Landsat, or USGS imagery, each of which is in the public domain.
In version 5.0, Google introduced Historical Imagery, allowing users to view earlier imagery. Clicking the clock icon in the toolbar opens a time slider, which marks the time of available imagery from the past. This feature allows for observation of an area's changes over time. Utilizing the timelapse feature allows for the ability to view a zoom-able video as far back as 38 years.
3D imagery
Google Earth shows 3D building models in some cities, including photorealistic 3D imagery made using photogrammetry. The first 3D buildings in Google Earth were created using 3D modeling applications such as SketchUp and, beginning in 2009, Building Maker, and were uploaded to Google Earth via the 3D Warehouse. In June 2012, Google announced that it would be replacing user-generated 3D buildings with an auto-generated 3D mesh. This would be phased in, starting with select larger cities, with the notable exception of cities such as London and Toronto which required more time to process detailed imagery of their vast number of buildings. The reason given is to have greater uniformity in 3D buildings and to compete with Nokia Here and Apple Maps, which were already using this technology. The coverage began that year in 21 cities in four countries. By early 2016, 3D imagery had been expanded to hundreds of cities in over 40 countries, including every U.S. state and encompassing every continent except Antarctica.In 2009, in a collaboration between Google and the Museo del Prado in Madrid, the museum selected 14 of its paintings to be photographed and displayed at the resolution of 14,000 megapixels inside the 3D version of the Prado in Google Earth and Google Maps.
Street View
On April 15, 2008, with version 4.3, Google fully integrated Street View into Google Earth. Street View displays 360° panoramic street-level photos of select cities and their surroundings. The photos were taken by cameras mounted on automobiles, can be viewed at different scales and from many angles, and are navigable by arrow icons imposed on them.Using Street View on Google Earth, users can visit and explore 30 UNESCO World Heritage Sites with historical context and pins for each. The sites include the Great Pyramid, the Taj Mahal, Sagrada Família, the Dolomites, the Royal Botanic Gardens, Kew, and the Great Sphinx.
In 2019, Walt Disney World and Pixar partnered with Google to create Pixar Street View. A unique activation that enabled viewers to search for hidden Pixar Easter eggs inside Toy Story Land at Disney's Hollywood Studios through street view. This creative collaboration elevated Pixar's iconic tradition of hiding Easter eggs in films and introduced it to an immersive new platform.
Water and ocean
Introduced in Google Earth 5.0 in 2009, the Google Ocean feature allows users to zoom below the surface of the ocean and view the 3D bathymetry. Supporting over 20 content layers, it contains information from leading scientists and oceanographers. On April 14, 2009, Google added bathymetric data for the Great Lakes.In June 2011, Google increased the resolution of some deep ocean floor areas from 1-kilometer grids to 100 meters. The high-resolution features were developed by oceanographers at Columbia University's Lamont–Doherty Earth Observatory from scientific data collected on research cruises. The sharper focus is available for about 5 percent of the oceans. This can be seen in the Hudson off New York City, the Wini Seamount near Hawaii, and the Mendocino Ridge off the U.S. Pacific coast.