A viewshed is an area of land, water, or other environment

Natural environment

The natural environment encompasses all living and non-living things occurring naturally on Earth or some region thereof. It is an environment that encompasses the interaction of all living species....

al element that is visible to the human eye from a fixed vantage point. The term is used widely in such areas as urban planning

Urban planning

Urban planning incorporates areas such as economics, design, ecology, sociology, geography, law, political science, and statistics to guide and ensure the orderly development of settlements and communities....

, archaeology

Archaeology

Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

, and military science

Military science

Military science is the process of translating national defence policy to produce military capability by employing military scientists, including theorists, researchers, experimental scientists, applied scientists, designers, engineers, test technicians, and military personnel responsible for...

. In urban planning, for example, viewsheds tend to be areas of particular scenic or historic value that are deemed worthy of preservation against development or other change. Viewsheds are often spaces that are readily visible from public areas such as from public roadways, public parks or high-rise buildings. The preservation of viewsheds is frequently a goal in the designation of open space

Open space reserve

Open space reserve, open space preserve, and open space reservation, are planning and conservation ethics terms used to describe areas of protected or conserved land or water on which development is indefinitely set aside...

 areas, green belt

Green belt

A green belt or greenbelt is a policy and land use designation used in land use planning to retain areas of largely undeveloped, wild, or agricultural land surrounding or neighbouring urban areas. Similar concepts are greenways or green wedges which have a linear character and may run through an...

s, and community separator

Community separator

In urban planning in the United States, a community separator is a parcel of undeveloped land, sometimes in the form of open space, separating two or more urban areas under different municipal jurisdictions which has been designated to provide a permanent low-density area preserving the communal...

s.

In digital imaging

Digital imaging

Digital imaging or digital image acquisition is the creation of digital images, typically from a physical scene. The term is often assumed to imply or include the processing, compression, storage, printing, and display of such images...

, a viewshed may be a binary

Binary numeral system

The binary numeral system, or base-2 number system, represents numeric values using two symbols, 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2...

 raster

Raster graphics

In computer graphics, a raster graphics image, or bitmap, is a data structure representing a generally rectangular grid of pixels, or points of color, viewable via a monitor, paper, or other display medium...

 indicating the visibility of a viewpoint for or from an area of interest. A pixel

Pixel

In digital imaging, a pixel, or pel, is a single point in a raster image, or the smallest addressable screen element in a display device; it is the smallest unit of picture that can be represented or controlled....

 with a value of unity indicates that the viewpoint is visible from that pixel, while a value of zero indicates that the viewpoint is not visible from the pixel. In certain disciplines, such as radio communications, 'visibility' may be probabilistic, therefore viewshed may be represented with non-integer values.

In radio

Radio

Radio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...

, a viewshed is the area where a specific combination of transmitter, antenna, and terrain allow reception of signal.

See also

• Scenic highway
• Zone of Visual Influence
  Zone of Visual Influence
  A Zone of Visual Influence is the area from which a development is theoretically visible. It is usually represented as a map using color to indicate visibility....
  
  
• Isovist
  Isovist
  A single isovist is the volume of space visible from a given point in space, together with a specification of the location of that point. Isovists are naturally three-dimensional, but they may also be studied in two dimensions: either in horizontal section or in other vertical sections through...
  
  
• Computational archaeology
  Computational archaeology
  Computational archaeology describes computer-based analytical methods for the study of long-term human behaviour and behavioural evolution. As with other sub-disciplines that have prefixed 'computational' to their name Computational archaeology describes computer-based analytical methods for the...
  
  
• Visibility (geometry)
  Visibility (geometry)
  Visibility is a mathematical abstraction of the real-life notion of visibility.Given a set of obstacles in the Euclidean space, two points in the space are said to be visible to each other, if the line segment that joins them does not intersect any obstacles.Computation of visibility is among the...
  
  
• Viewshed Analysis