- Positive images which are contact printed onto transparent mylar film at the same size and scale as the negative.
Used most often in stereoplotters for mapping and orthophoto development.
- A GPS receiver mounted in the aircraft, by locking onto several navigation satellites, maintains a constant spatial
positioning record. This information is used to calculate the geographic coordinates of the camera position.
- Also known as photo triangulation, control bridging and air trig, analytical aerotriangulation is the
determination of horizontal and vertical photogrammetric control points, based on project datum, from measurements of
overlapping aerial photographs and known ground control points.
- A computer representation of the terrain surface consisting of spot elevation data. DEM data can be used for
orthophoto rectification, but is not adequate for contour determination.
A completely rectified copy of an original photograph. All variations in scale and displacements, due to relief,
have been eliminated, hence the name ortho (correct) photography. Orthophoto and orthophoto map are synonymous, an
orthophoto is, very simply, a photomap.
- A device in the camera which compensates for the forward motion of the aircraft while the shutter is open. FMC
reduces blurring of the photographic image.
- A collection of graphic and attribute data relating to the earth's surface, computer hardware and software, which
are used to perform queries of the data and to create thematic maps.
- Surveying systems which can isolate the position of a point on the earth's surface by making simultaneous
observations on several orbiting navigational satellites.
- A point or points established by ground survey methods used to determine scale and orientation of aerial photography. Frequently used as a base for analytical aerotriangulation or photogrammetric control.
- The creation of a map, or portion thereof, from aerial photographs and geodetic control data, by means of
photogrammetric instruments. Stereo compilation is performed while viewing a three-dimensional photographic model with
a stereo plotting instrument.
- A set of standards, generally accepted by public and private sectors, established by the United States Government,
Office of Management and Budget, (The Photogrammetry for Highways Committee, 1968) which specify the accuracy standards
for planimetric and topographic map features. Source: Manual of Photogrammetry, Fourth Edition.
- The process of preparing a photographic image from perspective photography by removing displacement points caused
by tilt, relief and central projection perspective.
- The science and technology of deducting the physical dimensions of objects from measurements on photographs.
To obtain reliable information about physical objects and the environment, through processes of recording, measuring
and interpreting images.
- Those parts of a map which represent everything except relief, that is features which represent the works of man such as buildings and roads, and natural features such as woods and water.
- A computerized composite of picture elements (pixels) or individual dots, each of which has a gray scale or color
value, that when viewed together comprise an image. Examples: scanned photographs and satellite images.
- A computer used for stereoscopic viewing and measuring of aerial photography. These instruments are capable of recording measurements in a suitable format for plotting.
- One of the plane rectangular coordinate systems, one for each State in the Union, established by the U.S. Coast and Geodetic Survey for use in specifying locations of geodetic stations in terms of plane rectangular Cartesian coordinates. Most states are individually mapped by a conformal map projection in one or more zones, over each of which is placed a rectangular grid. A relationship between the rectangular grid and the graticule generated by the map projection is established mathematically. Zones of limited extent east-west and indefinite extent north-south are mapped by the Lambert conformal conic map projection with two standard parallels. All such geodetic locations determined by the U.S. National Geodetic Survey (NGS) are transformed into plane rectangular coordinates on the proper grid, and distributed by the NGS together with the geodetic coordinates.
- A software/hardware unit which interjects the generated digital map data into the optical path of the stereoplotter and reproduces it directly on top of the spatial photo image. Superimposition allows simultaneous viewing of the photographic image and mapping data being compiled.
- The distinctive marking of a ground point to aid in its identification on a photograph. In photogrammetry, a target designates a material marking so arranged and placed on the ground as to form a distinctive pattern over a geodetic or other control point marker, on a property corner or line, or at the position of an identifying point above an underground feature.
