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Aerial photograph - A photograph taken vertically downward from the air. Aerial photograph images may be in the form of paper
prints, often 9" x 9", or transparent film.
Attribute - An attribute is a set or collection of data that describe the characteristics of real world entities or conditions. Attribute
data are usually alphanumeric. Small amounts of attribute data are frequently used to describe the graphic representation of an entity
on a map as a label, e.g., a polygon label. Large amounts of attribute data are usually maintained as separate attribute data sets,
related to a map by names or codes.
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B/W photo, B/W image, or B/W display (or B&W) - A black and white photograph or some other monochrome image rendered in
black, white, and shades of gray.
Bitmap - An image stored as a pattern of dots (or pels).
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Cadastral layer - A set of information depicting the pattern of land ownership rights in an area. The
layer is typically based on legal descriptions tied to elements of the geodetic control network available in an area.
Cadastral Mapping - A mapping endeavor with ownership and value being the primary concerns. Principal usage is for tax analysis.
Cartography - The art or science of making maps.
Composite map - A single map created by joining together several separately digitized or scanned maps.
Contour - (noun) An imaginary line on the ground, all points of which are at the same elevation above or below a specific datum
surface, usually mean sea level.
Contour - (verb) Given a set of regularly or irregularly spaced point values, interpolate contours at user specific intervals.
Contour map - A topographic map that uses contour lines to portray relief. Contour lines join points of equal elevation.
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Data set - (Data file) A named collection of logically related data records arranged in a prescribed manner. The physical set of data of
one data type being referred to or being used in the context of a data processing operation.
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GIS - Geographic Information System. A Geographic Information System is a computer system designed to allow users to collect,
manage, and analyze large volumes of spatially referenced and associated attribute data. The major components of a GIS are: a user
interface system; data base management capabilities; data base creation/data entry capacity; spatial data manipulation and analysis
packages; and display/product generation functions.
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Land information system (LIS) - A geographic information system having, as its main focus, data containing land records. Land
records are broadly defined to include resource, land use, environmental impact, and fiscal data.
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Map - (Cartography) A hand-drawn or printed document describing the spatial distribution of geographical features in terms of a
recognizable and agreed symbolism. (Digital) The collection of digital information about the a part of the Earth’s surface.
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Orthophotograph - An aerial photograph that has been scanned, rectified, and reconstructed so as to represent its features in a map
projection or at least in a flat rectangular form without the usual distortions of geometry and perspective. Usually orthophotos are
prepared from very high resolution stereo pairs.
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Photogrammetry - Obtaining precise measurements from images.
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Sample - A group of cells in an image selected to represent one feature type or land cover of interest.
Scale or map scale - The relationship that exists between a distance on a map and the corresponding distance on the Earth. It may be
expressed as an equivalence, one inch equals 16 statute miles; as a fraction or ratio, 1:1,000,000; or as a bar graph subdivided to show
the distance that each of its parts represents on the Earth.
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Tesselation - The process of splitting an area into tiles. (See also Dirichlet tesselation)
Topographic map, or topo map - A map that uses colors and symbolic patterns to represent the general surface features of the earth,
such as grassland, forest, marsh, agricultural, urban, and barren rock.
Topography - The features of the actual surface of the Earth, considered collectively according to their form (grassland, cultivated,
desert, forest, swamp, etc.). A single feature, such a one mountain or one valley, is called a topographic feature.
Topological - Referring to properties of geometric figures, such as adjacency, that are not altered by distortion as long as the surface
is not torn.
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