A digital elevation model (DEM) or digital surface model (DSM) is a 3D computer graphics representation of elevation data to represent terrain or overlaying objects, commonly of a planet, moon, or asteroid. A "global DEM" refers to a discrete global grid. DEMs are used often in geographic information systems (GIS), and are the most common basis for digitally produced relief maps. A digital terrain model (DTM) represents specifically the ground surface while DEM and DSM may represent tree top canopy or building roofs.
Imagery intelligence (IMINT), pronounced as either as Im-Int or I-Mint, is an intelligence gathering discipline wherein imagery is analyzed to identify information of intelligence value. Imagery used for defense intelligence purposes is generally collected via satellite imagery or aerial photography.
The Moderate Resolution Imaging Spectroradiometer (MODIS) is a satellite-based sensor used for earth and climate measurements. There are two MODIS sensors in Earth orbit: one on board the Terra satellite, launched by NASA in 1999; and one on board the Aqua satellite, launched in 2002. MODIS has now been replaced by the VIIRS, which first launched in 2011 aboard the Suomi NPP satellite.
Landsat 7 is the seventh satellite of the Landsat program. Launched on 15 April 1999, Landsat 7's primary goal is to refresh the global archive of satellite photos, providing up-to-date and cloud-free images. The Landsat program is managed and operated by the United States Geological Survey, and data from Landsat 7 is collected and distributed by the USGS. The NASA WorldWind project allows 3D images from Landsat 7 and other sources to be freely navigated and viewed from any angle. The satellite's companion, Earth Observing-1, trailed by one minute and followed the same orbital characteristics, but in 2011 its fuel was depleted and EO-1's orbit began to degrade. Landsat 7 was built by Lockheed Martin Space Systems.
Aerial archaeology is the study of archaeological remains by examining them from a higher altitude. In present day, this is usually achieved by satellite images or through the use of drones.
DigitalGlobe was an American commercial vendor of space imagery and geospatial content, and operator of civilian remote sensing spacecraft. The company went public on the New York Stock Exchange on 14 May 2009, selling 14.7 million shares at US$19.00 each to raise US$279 million in capital. On 5 October 2017, Maxar Technologies completed its acquisition of DigitalGlobe.
NASA WorldWind is an open-source virtual globe. According to the website, "WorldWind is an open source virtual globe API. WorldWind allows developers to quickly and easily create interactive visualizations of 3D globe, map and geographical information. Organizations around the world use WorldWind to monitor weather patterns, visualize cities and terrain, track vehicle movement, analyze geospatial data and educate humanity about the Earth." It was first developed by NASA in 2003 for use on personal computers and then further developed in concert with the open source community since 2004. As of 2017, a web-based version of WorldWind is available online. An Android version is also available.
Satellite images are images of Earth collected by imaging satellites operated by governments and businesses around the world. Satellite imaging companies sell images by licensing them to governments and businesses such as Apple Maps and Google Maps.
Microsoft Research Maps was a free online repository of public domain aerial imagery and topographic maps provided by the United States Geological Survey (USGS). The site was a collaboration between Microsoft Research (MSR), Bing Maps, and the USGS. It was in operation from June 1998 to March 2016. It had 30,000 to 50,000 visitors per day as of January 2010. The site was renamed in 2010, prior to which it had been known as TerraServer-USA.
Terraserver may refers to either of two databases for viewing geospatial imagery:
Yahoo! Maps was a free online mapping portal provided by Yahoo! Functionality included local weather powered by The Weather Channel, printing maps, and local reviews powered by Yelp. It shut down on June 30, 2015. For a time in 2019, Yahoo! Maps could be accessed in the United States on https://search.yahoo.com/, albeit powered by Here WeGo. However, that is no longer possible.
GlobeXplorer was an online spatial data company that compiled and distributed aerial photos, satellite imagery, and map data from their online spatial archives. GlobeXplorer has been credited as the first company to establish a business around compiling and distributing online aerial and satellite imagery. In 2007, the company was acquired by DigitalGlobe.
Google Earth is a computer program 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 has revealed that Google Earth now covers more than 97 percent of the world, and has captured 10 million miles of Street View imagery.
A virtual globe is a three-dimensional (3D) software model or representation of Earth or another world. A virtual globe provides the user with the ability to freely move around in the virtual environment by changing the viewing angle and position. Compared to a conventional globe, virtual globes have the additional capability of representing many different views of the surface of Earth. These views may be of geographical features, man-made features such as roads and buildings, or abstract representations of demographic quantities such as population.
Earth Satellite Corporation (EarthSat), an American company, was a pioneer in the commercial use of Earth observation satellites. Founded in 1969, EarthSat was first headquartered in Washington, D.C., and later moved its offices to Bethesda, Maryland, and finally to Rockville, Maryland, in the late 1980s. In 2001, EarthSat was acquired by MacDonald, Dettwiler and Associates Ltd. (MDA) of Vancouver, British Columbia. In August 2005, EarthSat was incorporated as MDA Federal Inc., the U.S. operation of MDA Geospatial Services.
Bing Maps is a web mapping service provided as a part of Microsoft's Bing suite of search engines and powered by the Bing Maps Platform framework. Since 2020, the map data is provided by TomTom.
GeoEye Inc. was an American commercial satellite imagery company based in Herndon, Virginia. GeoEye was merged into the DigitalGlobe corporation on January 29, 2013.
Multispectral remote sensing is the collection and analysis of reflected, emitted, or back-scattered energy from an object or an area of interest in multiple bands of regions of the electromagnetic spectrum. Subcategories of multispectral remote sensing include hyperspectral, in which hundreds of bands are collected and analyzed, and ultraspectral remote sensing where many hundreds of bands are used. The main purpose of multispectral imaging is the potential to classify the image using multispectral classification. This is a much faster method of image analysis than is possible by human interpretation.
Planet Labs PBC is an American public Earth imaging company based in San Francisco, California. Their goal is to image the entirety of the Earth daily to monitor changes and pinpoint trends.
PrecisionHawk is a commercial drone and data company. Founded in 2010, PrecisionHawk is headquartered in Raleigh, North Carolina with another global office in Toronto, Canada and satellite offices around the world. PrecisionHawk is a manufacturer of drones (Lancaster) and has more recently focused heavily on developing software for aerial data analysis (DataMapper) and drone safety systems (LATAS). PrecisionHawk is a member of the U.S. Federal Aviation Administration Pathfinder Initiative and the NASA UTM Program. An angel investor in the company, Bob Young, founder of Red Hat, became CEO in August 2015. In August 2016, PrecisionHawk became the first U.S. company to receive an FAA exemption to commercially fly drones beyond the operator's visual line of sight.
