Geography, asked by mannatsingh45580, 4 months ago

Make a project by collecting data from secondary sources(using modern techniques i,.e. GPS, aerial photography and satellite images)on dangers of development. Thoda sa lengthy bhi kr dena. Plz plz plz hlp krdo.Its importnt.​


hemanji2007: hope it helps you
mannatsingh45580: Aww so nice of u
mannatsingh45580: Thnq
hemanji2007: it's ok

Answers

Answered by hemanji2007
3

The U.S. Geological Survey and Remote Sensing

Photographs and other images of the Earth taken from the air and from space show a great deal about the planet's landforms, vegetation, and resources. Aerial and satellite images, known as remotely sensed images, permit accurate mapping of land cover and make landscape features understandable on regional, continental, and even global scales. Transient phenomena, such as seasonal vegetation vigor and contaminant discharges, can be studied by comparing images acquired at different times.

The U.S. Geological Survey (USGS), which began using aerial photographs for mapping in the 1930's, archives photographs from its mapping projects and from those of some other Federal agencies. In addition, many images from such space programs as Landsat, begun in 1972, are held by the USGS. Most satellite scenes can be obtained only in digital form for use in computer-based image processing and geographic information systems, but in some cases are also available as photographic products.

How Images Are Categorized

Remotely sensed images are usually categorized according to the altitude of the aircraft or spacecraft and the characteristics of the sensors used to generate the images.

Altitude

Satellites, including manned spacecraft, usually collect images from hundreds of miles above the Earth's surface while aircraft operate at altitudes from a few thousand to more than 60,000 feet. The altitude from which an image is taken and the physical characteristics of the sensor, such as the lens focal length in the case of cameras, largely determine the area covered and the amount of detail shown. In general, the level of detail is greater in low-altitude photographs that cover relatively small areas, while satellite images cover much larger areas but show less detail.

Sensor and Media Characteristics

A fals color aerial photograph showing the water falls and building around it.

Figure 7: Horseshoe Falls (Niagra Falls), N.Y. and Canada, looking south, low oblique color-infrared aerial photograph, Environmental Protection Agency, August 1974

Aerial photographs are produced by exposing film to solar energy reflected from Earth. Photographic media have been used for aerial reconnaissance since the middle of the 1860's; color film became widely used in the 1950's. Color-infrared film, which records energy from portions of the electromagnetic spectrum invisible to the human eye, was developed to detect camouflaged military objects in the 1940's. In a color-infrared (also known as false-color) photograph, near-infrared light reflected from the scene appears as red, red appears as green, green as blue, and blue as black. Color-infrared film is useful for distinguishing between healthy and diseased vegetation, for delineating bodies of water, and for penetrating atmospheric haze.

Black-and-white and color-infrared films are used today in both high- and low-altitude aerial photography. Natural-color film is used more rarely because it is often affected by atmospheric haze.

Attachments:
Similar questions