National Geospatial-Intelligence Agency
One of the agencies of the United States intelligence community and also within the United States Department of Defense, the National Geospatial-Intelligence Agency (NGA) is a merger of geodesic survey, mapmaking, and orgaizations. NGA also develops the extremely detailed terrain contour images used by cruise missiles that use terrain-matching guidance. It is also an authoritative source for navigational references.
It replaced the CIA-operated National Photo-Interpretation Center, and is responsible for production of imagery intelligence and the superset, geospatial intelligence. It does not operate the satellites, aircraft, and unmanned aerial vehicles that take the pictures; that is the role of the National Reconnaissance Office and tactical military organizations.
Survey and mapping tradition
According to the NGA history, "The US geospatial intelligence effort began in 1803 when President Thomas Jefferson sent the Army’s Lewis and Clark expedition to explore and map the recently acquired Louisiana Territory. As the Army, assisted by its contract civilian scientists, supported the country’s westward expansion, the Navy similarly began reaching out across the oceans. This maritime expansion, coupled with the Navy's desire not to have to rely on British or commercial charts, led to the establishment of the Navy Depot of Charts and Instruments in 1830."
"US mapping and charting efforts remained relatively unchanged until World War I, when aerial photography became a major contributor to battlefield intelligence. Using stereo viewers, photointerpreters reviewed thousands of images. Many of these were of the same target at different angles and times, giving rise to what became modern imagery analysis and mapmaking. After the war, as airplane capacity and range improved, the need for charts grew."
After the Vietnam War, the need for economy, maximum use of new technologies, and reduced human resources led to the armed services combining most of their mapping and charting capabilities into one organization, resulting in the formation of the Defense Mapping Agency in 1972.
The advent of ballistic missiles and the greater use of satellites made understanding the precise shape and gravity field of the Earth an important area for the national security. 
Imagery and geospatial intelligence
Aerial photography, meanwhile, had become far more sophisticated than the original imagery intelligence, which were drawings made from hot air balloons in the American Civil War. The first disciplined interpretation came in World War I, when specialists learned to draw inferences from multiple views of the same target, taken at different times, altitudes, and angles. Imagery became part of the mapmaking process "After the war, as airplane capacity and range improved, the need for charts grew.
The combination of images with other information, such as geographic references, produces geospatial intelligence, an enhanced version of imagery intelligence. Other adjuncts to photographic images come from imaging radar and from electro-optical MASINT techniques such as multispectral scans of the areas photographed.
The institutionalization of image interpretation
With the advent both of high-altitude photographic aircraft such as the U-2, as well as photographic satellites,President Dwight D. Eisenhower ordered the creation of the National Photo-Interpretation Center (NPIC), headed by Art Lundahl from the CIA and with staff from all the military services.
The actual taking of the pictures was not an NPIC responsibility. Images taken from aircraft were made by the military services, while the National Reconnaissance Office launched and operated reconnaissance satellites.
NPIC played a vital role in the Cuban Missile Crisis, and in subsequent crises involving even more sophisticated sensors. "In 1996, the US Congress, the CIA, and the Department of Defense agreed to combine the efforts of the country’s mapping and imagery analysis efforts, creating the National Imagery and Mapping Agency (NIMA). Formed from several defense and intelligence agencies, NIMA merges imagery, maps, charts, and environmental data to produce what has been coined 'geospatial intelligence." Reflecting the growth of the geospatial intelligence discipline, NIMA changed its name to NGA in 2003.