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Term Definition/Description Source
face 1. (imagery) The emulsion side of a negative or layout plate, or the printing surface of a plate. 2. (topology) A two-dimensional topological entity defined as an undivided area surrounded by topological edges representing all or part of the extent of a feature or of an attributed area. HDBK-850
face A minimum 2-dimensional structure primitive defined by one outer ring and zero to many inner rings. ISO/TC 211
face A region enclosed by an edge or set of edges (a face has an area). Faces are topologically linked to their surrounding edges as well as to the other faces that surround them. Faces are always non overlapping, exhausting the area of the plane. VPF Glossary
facility (UCDM Entity: "FACILITY") Real property, having a specified use, that is built or maintained by people. USIGS/CDM-A
facility A collection of object services, with additional functionality, that is used for a specific purpose. UTA-A
facsimile chart See modified facsimile chart. HDBK-850
factored transparency A system of radar simulation which utilizes a pair of photographic images on a glass plate or plates to store topographic and radar reflection data. The data are scanned by a flying-spot scanner cathode-ray tube, and the density of the images is read by two photomultiplier tubes. The two planar dimensions of the two images are the x- and y-dimensions of the topographic and reflectance data respectively. The densities of the reflectance images are used to store the intrinsic strength of radar target reflectance. The images are identical in their x- and y-values but separated in one dimension by the optical spacing of the dual readout system. Also called land mass simulator plate. HDBK-850
factory acceptance test (FAT) A formal test of the system under procurement in the manufacturer's environment in order to verify successful production of hardware or software. Recipient personnel witness the test to verify requirements and successful product generation before the system is shipped to the recipient. HDBK-850
FAF block See fast access format (FAF) block. HDBK-850
Failure Transparency A distribution transparency which masks, from an object, the failure and possible recovery of other objects (or itself), to enable fault tolerance. RM-ODP
falling The distance by which a random line falls to the right or left of a corner on which the true line is too close. Usually the direction of falling is expressed as cardinal. HDBK-850
falling tide See ebb tide. HDBK-850
false bearing The difference between the true bearing and the back bearing caused by the convergence of meridians. HDBK-850
false color (photogrammetry) See infrared. HDBK-850
false easting A value assigned to the origin of eastings, in a grid coordinate system, to avoid the inconvenience of using negative coordinates. See also grid coordinates. HDBK-850
false fix probability A statistical value or ratio which reflects the likelihood of a false match occurring between prestored digital cartographic data and data or imagery acquired by electronic aerial sensor systems. See also image correlation; terrain contour matching (TERCOM); terrain correlation. HDBK-850
false horizon A line resembling the visible horizon, but above or below it. HDBK-850
false northing A value assigned to the origin of northings, in a grid coordinate system, to avoid the inconvenience of using negative coordinates. See also grid coordinates. HDBK-850
false origin (JCS) A fixed point to the south and west of a grid zone from which grid distances are measured eastward and northward. See also grid origin. HDBK-850
false parallax (JCS) The apparent vertical displacement of an object from its true position when viewed stereoscopically, due to movement of the object itself as well as to change in the point of observation. HDBK-850
false stereo An imaginary impression of stereoscopic relief. See also pseudoscopic stereo. HDBK-850
falsification testing A test method developed to find errors in the implementation. NOTE - If errors are found, one can correctly deduce the implementation does not conform to the standard; however, the absence of errors does not necessarily imply the converse. Falsification testing can only demonstrate non-conformance. Compare with verification testing. Due to technical and economical problems, in most cases, falsification testing is adopted as a test method for conformance testing. ISO/TC 211
fan camera photography (JCS) Photography taken simultaneously by an assembly of three or more cameras, systematically installed at fixed angles relative to each other so as to provide wide lateral coverage with overlapping images. See also tricamera photography. HDBK-850
fan cameras (JCS) An assembly of three or more cameras systematically disposed at fixed angles relative to each other so as to provide wide lateral coverage with overlapping images. HDBK-850
far infrared A term for longer wavelengths of the infrared region, from 14 microns to 40 microns. USIS 95
far off-line data Digital data that are accessible through standard discovery mechanisms that require an operator to retrieve the media on which the data resides, but with response times ranging from several hours to one day. In this case, the media are far removed from the retrieving operator (in a different building). See also on-line data, near on-line data and off-line data. USIS 95
fast access format (FAF) A filing scheme for breaking digital imagery into smaller chunks of data. See also fast access format (FAF) block. HDBK-850
fast access format (FAF) block A FAF block is a block of 1024 X 1024 pixels of image data, or digitized raster graphics. USIS 95
fathogram A graphic record of depth measurements obtained by echo sounding equipment. Also called echogram. HDBK-850
fathom curve See depth contour. HDBK-850
fathom line See depth contour. HDBK-850
Fathometer A trade name for an echo sounder. HDBK-850
fault A situation that may cause errors to occur in an object. Faults can be accidental, intentional, physical, man-made, internal, external, permanent, or temporary. RM-ODP
Faye anomaly See free-air anomaly. HDBK-850
Faye correction See free-air correction. HDBK-850
featheredging 1. (cartography) The technique of progressively dropping contours, to avoid congestion on steep slopes, and tapering the line weight near the end of the contour to be dropped. Also called feathering. 2. (photomosaicking) The thinning of overlapping edges of photographs before assembling into a mosaic in order to make match lines less noticeable. When overlapping edges are feathered, shadows and sharp changes in contrast are reduced or eliminated. Also called feathering. HDBK-850
feathering See featheredging. HDBK-850
feature A digital representation of a real world entity or an abstraction of the real world. It has a spatial domain, a temporal domain, or a spatial/temporal domain as one of its attributes. Examples of features include almost anything that can be placed in time and space, including desks, buildings, cities, trees, forest stands, ecosystems, delivery vehicles, snow removal routes, oil wells, oil pipelines, oil spills, and so on. Features are usually managed in groups as feature collection. OpenGIS Guide
feature An attribute or characteristic of a system that is meaningful to, or directly affects, the user, developer, or other entity that interacts with a system. S/W Reuse
feature A set of characteristics, structures, or other entities associated with a geographic location. USIGS/CDM-A
feature analysis The process of locating, examining, and classifying the physical characteristics of cultural features on the earth's surface. HDBK-850
feature analysis code (FAC) number A unique number (usually sequential) assigned to each area or feature portrayed on the feature manuscript and used to relate feature analysis data table (FADT) information to the digital information which portrays the shape of the feature. See also feature analysis data table. HDBK-850
feature analysis data table (FADT) A table containing the feature analysis code numbers and the numeric codes which represent the physical characteristics of features selected for portrayal. See also feature analysis code (FAC) number. HDBK-850
Feature and Attribute Coding Catalog (FACC) FACC provides a means for encoding real world entities or objects forthe purpose of an orderly exchange of digital geospatial information between organizations. FACC describes the world in terms of features and attributes. Attributes are the properties, or characteristics associated with features. Standards for digital geographic information (DGI) exchange require a standard method for documenting features and attributes necessary to distinguish those features commonly found in Mapping, Charting, and Geodesy (MC&G), and Geographic Information Systems (GIS), and for the orderly exchange of such data between MC&G organizations. FACC is contained within the Digital Geographic Information Exchange Standard (DIGEST), Part 4. DIGEST Web Site
feature attribute An essential trait, quality, or characteristic of a geographic feature. ISO/TC 211
feature attribute type A type of characteristic relevant for features belonging to a certain feature type. ISO/TC 211
feature catalogue A definition and description of the feature types, feature type functions, feature attribute types, and feature relationship types occurring in one or more sets of geographic data. ISO/TC 211
feature class A set of features sharing a consistent set of attribute types. A feature class is implemented by using a set of tables that includes at least one primitive table and at least one attribute table. A feature class has the same columns (attribute types) of attribute information for each feature. Classes of features are created in order to allow the relational model to operate on them as sets. Every feature class has one and only one feature table. HDBK-850
feature code A unique identifier assigned to a feature. HDBK-850
feature collection A set of related features managed as a group. OpenGIS Guide
feature element The part of a geographic feature that can be identified and treated separately. ISO/TC 211
feature extraction Detection, identification, classification, attribution, annotation, measurement, and delineation in three dimensions of both geomorphic and cultural features. USIS 95
Feature Extraction Segment (FE/S) A segment of DMA's [NIMA's] MARK 85 which implements a computer supported, analytical stereoplotter system capable of extracting feature data. This segment integrates, on a single system, all of the various steps involved in the mostly manual feature extraction process prior to DPS. See also MARK 85; Digital Production System (DPS). HDBK-850
feature identification data (FID) Information pertaining to the classification of a feature as to kind, function, and description, e.g., heavy fabrication industry with saw-tooth roof; truss bridge; powerline pylon, etc. Each classification has a unique feature identification code. See also feature analysis data table, feature analysis code; feature analysis. HDBK-850
feature operation The behaviour of a specific feature. ISO/TC 211
feature operation type The type of behaviour of a feature type. ISO/TC 211
feature relationship The logical link between features. NOTE - A feature may have a feature relationship to itself. ISO/TC 211
feature relationship type The characteristic or behaviour that links instances of one feature type with other instances of the same or a different feature type. ISO/TC 211
feature representation A single occurrence of a feature representation type. ISO/TC 211
feature representation type A digital representation of a feature type. ISO/TC 211
feature table A table made up of the primary-keyed rows of the features in a feature class. These rows collectively form the feature table for that feature class. HDBK-850
feature type A classification of features into three categories: (1) point of feature - an object whose location can be described by a single set of coordinates; (2) linear (or lines) feature - portrayed by a line that does not represent an area; (3) areal feature - a topographic feature, such as sand, swamp, vegetation, etc., which extends over an area or in digital mapping any area enclosed by a delimiting line that has any unique characteristic, e.g., industrial area, forest, residential area, etc. Feature type is thus an attribute defining the topologic property of a feature (point, line, or area). HDBK-850
feature type A class of features with common characteristics. ISO/TC 211
feature type (UCDM Entity: "FEATURE-TYPE") A class of features. USIGS/CDM-A
feature type function Behaviour common to all instances of a feature type. EXAMPLE - A function of the feature type 'bridge' is to carry traffic across a watercourse. Another function might be to block vessels from navigating along the watercourse. NOTE - Functions provide a basis for feature type definition. ISO/TC 211
Feature/Attribute Coding Standard (FACS) DMA [NIMA] standard for assigning features, attributes, values, and relationships to all digital entities under the Digital Production System. See also Feature and Attribute Coding Catalog. HDBK-850
feature-oriented A term used to describe the approach for encoding geographic entities in which a series of interrelated geographic objects are organized into a network-like structure of data and predefined relationships. HDBK-850
Federal Geographic Data Committee (FGDC) The FGDC is an interagency committee that promotes the coordinated use, sharing, and dissemination of geospatial data on a national basis. The FGDC was established in 1990 by the Office of Management and Budget (OMB) to coordinate the federal government's development of a National Spatial Data Infrastructure (NSDI). The NSDI encompasses policies, standards, and procedures for organizations to cooperatively produce and share geographic data. The FGDC, composed of representatives from fifteen Cabinet level and independent federal agencies, are developing the NSDI in cooperation with organizations from state, local and tribal governments, the academic community, and the private sector. The FGDC Staff Directorate is located at the United States Geological Survey (USGS) in Reston, VA. FGDC Web Site
Federal Geographic Data Committee (FGDC) (UCDM Entity: "FGDC") The Federal Geographic Data Committee defined the Content Standards for Digital Geospatial Metadata. The purpose of the standard is to provide a common set of terminology and definitions for concepts related to these metadata. (TBR) This entity documents attributes that are mandatory to conform with the FGDC standard. USIGS/CDM-A
Federal Information Processing Standards (FIPS) Official source within the Federal Government for information processing standards. FIPS are developed by the Institute for Computer Sciences and Technology at the National Institute of Standards and Technology (NIST, formerly called the National Bureau of Standards). HDBK-850
federate A member of a HLA federation. All applications participating in a Federation are called Federates. In reality, this may include Federate Managers, data collectors, live entity surrogates, simulations, or passive viewers. (HLA Glossary: www.dmso.mil/projects/hla/docslib/hlagloss.html) JTA 2.0
federation A named set of interacting federates, a common federation object model, and supporting RTI, that are used as a whole to achieve some specific objective. (HLA Glossary: www.dmso.mil/projects/hla/docslib/hlagloss.html) JTA 2.0
federation A community of domains. RM-ODP
Federation Object Model (FOM) An identification of the essential classes of objects, object attributes, and object interactions that are supported by an HLA federation. In addition, optional classes of additional information may also be specified to achieve a more complete description of the federation structure and/or behavior. (HLA Glossary: www.dmso.mil/projects/hla/docslib/hlagloss.html) JTA 2.0
felt side The top or smooth side of paper that is contacted by the felt belt for extraction of moisture during manufacture. This is the correct side of the paper for printing. HDBK-850
fence 1. A line of readout or tracking stations for pickup of signals from an orbiting satellite. 2. A line or network of radar or radio stations for detection of a satellite in orbit. HDBK-850
fermenting dough theory See Pratt-Hayford theory of isostasy. HDBK-850
ferrotype To burnish photographic prints by squeegeeing wet upon a japanned sheet of iron or stainless plate and allowing to dry. This produces a harder, glossier surface on the photographic print. HDBK-850
Fiber Distributed Data Interchange (FDDI) An ANSI LAN standard physical access media which utilizes a token passing ring technique and supports data rates of 100 megabits per second. [DISA/DO3 (CIO)] DISA CFS
fiber optics A device for relaying an image by means of a large number of transparent fibers (filaments) by multiple total internal reflection. The fibers are most commonly glass and less often a highly transparent plastic. Each fiber carries only one clement of the image, so that the image is a mosaic in which the cell size is the fiber cross section rather than a continuous picture. HDBK-850
fictitious In cartography, pertaining to or measured from an arbitrary reference line. HDBK-850
fictitious equator A reference line serving as the origin for measurement of fictitious latitude. HDBK-850
fictitious graticule The network of lines representing fictitious parallels and fictitious meridians on a map or chart. See also oblique graticule; transverse graticule. HDBK-850
fictitious latitude Angular distance from a fictitious equator. It may be called transverse, oblique, or grid latitude depending upon the type of fictitious equator. HDBK-850
fictitious longitude The arc of fictitious equator between the prime fictitious meridian and any given fictitious meridian. It may be called transverse, oblique, or grid longitude depending upon the type of fictitious meridian. HDBK-850
fictitious loxodrome See fictitious rhumb line. HDBK-850
fictitious loxodromic curve See fictitious rhumb line. HDBK-850
fictitious meridian One of a series of great circles or lines used in place of a meridian for certain purposes. It may be called transverse, oblique, or grid meridian depending upon the type of fictitious meridian. See also prime fictitious meridian. HDBK-850
fictitious parallel A circle or line parallel to a fictitious equator, connecting all points of equal fictitious latitude. It may be called transverse, oblique, or grid parallel depending upon the type of fictitious equator. HDBK-850
fictitious pole One of the two points 90 from a fictitious equator. It may be called transverse or oblique pole depending upon the type of fictitious equator. HDBK-850
fictitious rhumb line A line making the same oblique angle with all fictitious meridians. It may be called transverse, oblique, or grid rhumb line depending upon the type of fictitious meridian. Also called fictitious loxodrome; fictitious loxodromic curve. HDBK-850
fictitious sun A fictitious point termed the mean sun, which is imagined to move at a uniform rate along the Equator, its rate of motion being such that it makes one apparent revolution around the Earth in the same time as the actual Sun-that is, in 1 year. HDBK-850
fictitious year The period between successive returns of the Sun to a sidereal hour angle of 80 (about January 1). The length of the fictitious year is the same as that of the tropical year, since both are based upon the position of the Sun with respect to the vernal equinox. Also called Besselian year. HDBK-850
fidelity The degree with which a system accurately reproduces the data input into it. HDBK-850
fiducial axes The lines joining opposite fiducial marks on a photograph. The x-axis is generally considered to be the one nearly parallel with the line of flight. HDBK-850
fiducial mark(s) 1. (surveying) An index line or point. A line or point used as a basis of reference. 2. (JCS) (photogrammetry) See collimating marks. 3. Also, markers in any instrument which define the axes whose intersection fixes the principal point of a photograph and fulfills the requirements of interior orientation. HDBK-850
field calibration A term generally applied where only a combination of field and office computer techniques are available to check instrument accuracy. Adjustments, other than normal operator adjustments, cannot be made during field calibration. HDBK-850
field check The operation of checking a map compilation manuscript on the ground. See also field classification. HDBK-850
field classification Field inspection and identification of features which a map compiler is unable to delineate; identification and delineation of political boundary lines, place names, road classifications, buildings hidden by trees, and so forth. Field classification may be included as part of the control survey effort and normally is completed prior to the actual stereocompilation phase. See also field inspection. HDBK-850
field comparator A short line whose length is measured with accuracy and precision, and is used to check the lengths of apparatus (tapes) used in the actual field operations. Also called calibration course; comparator base. HDBK-850
field completion A combination of field inspections or surveys, either before or after compilation, to classify and complete the map content, correct erroneous data, and add information such as names, civil boundaries, and similar classification data. Its purpose is to fill in or confirm that portion of a map manuscript prepared by stereocompilation. HDBK-850
field contouring Contouring a topographic map by field methods accomplished by planetable surveys on a prepared base or by stadia survey. Generally, this operation applies to terrain unsuitable for contouring by photogrammetric methods. Also used in limited areas when engineering design (drainage) requires 1-foot contours. See also contour sketching. HDBK-850
field control (JCS) A series of points whose relative positions and elevations are known. These positions are used in basic data in mapping and charting. Normally, these positions are established by survey methods and are sometimes referred to as trig control or trigonometrical net (work). See also common control (artillery); control point; ground control. HDBK-850
field correction Adjustments made to field measurements, such as angles or distances, to correct for geometric or length discrepancies. HDBK-850
field correction copy A map or tracing prepared in the field, delineating corrections for subsequent reproduction of a map. HDBK-850
field elevation An elevation taken from the field computation of a line of levels. HDBK-850
field inspection The process of comparing aerial photographs with conditions as they exist on the ground, and of obtaining information to supplement or clarify that which is not readily discernible on the photographs themselves. Also called classification survey. HDBK-850
field intensity See field strength. HDBK-850
field of view (JCS) In photography, the angle between two rays passing through the perspective center (rear nodal point) of a camera lens to the two opposite sides of the format. Not to be confused with angle of view. See also angle of view. HDBK-850
field position A position computed while field work is in progress to determine the acceptability of the observations or to provide a preliminary position for other purposes. HDBK-850
field sheet The hydrographer's or topographer's work sheet; it presents a graphic display of all surface and subsurface features in the area being surveyed. See also boat sheet. HDBK-850
field standardization of tape The comparison of the length of a tape to be used for survey measurements with the length of a standard tape, to determine the true length of the former. HDBK-850
field stop The physical element (such as a stop, diaphragm, or lens periphery) of an optical system which limits the field of view covered by the system. See also aperture stop. HDBK-850
field strength For any physical field, the flux density, intensity, or gradient of the field at the point in question. Also called field intensity. HDBK-850
figure adjustment (surveying) The adjustment of a single chain of triangles made to satisfy the requirement that the sum of the angles in each triangle equals 180, and in the case of a quadrilateral that the sum of the angles equal 360. An office computation. HDBK-850
figure of the Earth See geoid. HDBK-850
filar micrometer A device attached to a telescope or microscope, consisting of a wire thread (filament) connected with a screw in such manner that as the screw is turned, the wire moves through a continuous succession of parallel positions, all in the focal plane of the instrument . HDBK-850
file Any specifically identified collection of information stored in the computer. [HCI Style Guide] DISA CFS
file structuring The logical form of a file that results from applying a particular file organization and layout to a group of records. HDBK-850
file transfer Data transfer using file transfer services. CEN/TC 287
File Transfer Protocol (FTP) A TCP/IP application program used to transfer files from one computer to another. It is commonly used on the Internet. [DISA/DO3 (CIO)] DISA CFS
file transfer services Communication services able to move a file from one point to another point in connection with each other through a data network or by unconnected media. CEN/TC 287
film A film base which is coated with a light sensitive emulsion for use in a camera or printing frame. See also aerial film; autoscreen film; cartographic film; infrared film; stable-base film; strip film; topographic base film. HDBK-850
film base A thin, flexible, transparent sheet of stable plastic material to which a light-sensitive emulsion may be applied. HDBK-850
film distortion The dimensional changes which occur in photographic film with changes in humidity or temperature, or from aging, handling, or other causes. HDBK-850
film mosaic See panel base. HDBK-850
film negative See negative, definition 1. HDBK-850
film positive See positive, definition 1. HDBK-850
film positives Sometimes referred to as "flats." Produced from a negative, this product is the basic product for exploitation on a light table. The product may be a single frame, part of a roll of film or even part of a frame. It is one of four product types under the category Imagery Collection Products (the other three being primary imagery records, imagery technical data, and duplicate negatives.) USIS 95
film titling See titling. HDBK-850
filter Any transparent material which, by absorption, selectively modifies the light transmitted through an optical system. HDBK-850
filtering The removal of certain spectral or spatial frequencies to enhance features in the remaining image. HDBK-850
final composite A composite of the principal color separations made after all corrections have been completed. HDBK-850
final operational capability A system reaches FOC when all deliverables are operational. USIS 95
Fire Support Coordination Center Marine Corps tactical targeting agency, established at each echelon of the Landing Force/ MAGTF, to implement fire support coordination responsibilities. USIS 95
FIREFINDER Elevation Data (FFED) Digitized triaxial coordinates collected on the preferred geodetic datum (usually World Geodetic System 1984 (WGS 84)) at 125 meter post spacing within 100 by 100 km areas. Values are collected from Digital Terrain Elevation Data (DTED) and transformed to Universal Transverse Mercator (UTM) coordinates, with vertical values assigned within 256 elevation bands defined between minimum and maximum values occurring in the area. Source tapes are a special-purpose National Imagery and Mapping Agency (NIMA) product that require dubbing onto field cassettes prior to use by the FIREFINDER system. The FIREFINDER provides high speed computation of mortar and field artillery firing positions from radar intercepts of projectile trajectories. NIMA LOP
firewall A type of router which is placed between a network and the internet to selectively filter incoming and outgoing traffic. Firewalls enhance network security. [DISA/DO3 (CIO)] DISA CFS
firing chart (JCS) Map, photomap, or grid sheet showing the relative horizontal and vertical positions of batteries, base points, base point lines, check points, targets, and other details needed in preparing firing data. HDBK-850
first approximation chart See historical chart. HDBK-850
first of Aries See first point of Aries; vernal equinox. HDBK-850
first point of Aries Also called first of Aries. See vernal equinox. HDBK-850
first point of Cancer See summer solstice, definition 1. HDBK-850
first point of Capricornus See winter solstice, definition 1. HDBK-850
first point of Libra See autumnal equinox. HDBK-850
first-order bench mark A bench mark connected to the datum (usually mean sea level) by continuous first-order leveling. HDBK-850
first-order level A leveling instrument which meets the following criteria: (1) the sensitivity of the level bubble vial must be 10'' of arc or less per division of 2 mm; (2) the instrument must be constructed of low expansion metal to minimize the effect of unequal heating; (3) the objective lens must have an effective opening of at least 40 mm and a magnification of 40X. HDBK-850
first-order leveling Spirit leveling conforming to the specifications of the current "Classification, Standards of Accuracy and General Specifications of Geodetic Control Surveys." Formerly known as precise leveling and leveling of high precision. Recommended for primary National Networks, as a basis for all subordinate elevation determinations, scientific studies such as crustal movement over large regions, extensive engineering projects such as hydroelectric dams. Such leveling generally includes the determination of geopotential values through simultaneous gravity measurements. HDBK-850
first-order traverse A survey traverse which extends between adjusted positions of other first-order control surveys and conforms to the current specifications of first-order traverse, per "Classification, Standards of Accuracy and General Specifications of Geodetic Control Surveys." HDBK-850
first-order triangulation First-order triangulation was at one time known as primary triangulation; changed in 1921 to precise triangulation; and in 1925 to first-order triangulation. These surveys conform to the current "Classification, Standards of Accuracy and General Specifications of Geodetic Control Surveys." Recommended for primary National Networks, as a basis for all subordinate surveys; metropolitan area surveys, where high value is attached to land and its line of communication frontage; and in scientific studies, such as crustal movement and space exploration. HDBK-850
first-order work The designation given survey work of the highest prescribed order of precision and accuracy. Such surveys were formerly called primary. HDBK-850
Fischer ellipsoid of 1960 A reference ellipsoid with two primary uses. In the Mercury datum it has the approximate dimensions of semimajor axis - 6,378,166.0 meters, and the flattening or ellipticity - 1/298.3. In the South Asia datum the semimajor axis is 6,378,155.0 meters, and the flattening or ellipticity is 1/298.3. HDBK-850
Fischer level A dumpy level capable of first-order leveling. HDBK-850
fitness for use The totality of characteristics of a product that bear on its ability to satisfy the requirements of an application. NOTE - Within the data quality model, fitness for use is an evaluation, usually made by a data user, of the appropriateness of a dataset for a specific need or application. ISO/TC 211
fix A relatively accurate position determined without reference to any former position, from terrestrial, electronic, or astronomic data Also, the point thus established. HDBK-850
fixed elevation An elevation which has been adopted, either as a result of tide observations or previous adjustment of spirit leveling, and which is held at its accepted value in any subsequent adjustment. HDBK-850
fixed position See adjusted position. HDBK-850
fixed satellite See synchronous satellite. HDBK-850
fixed-length records A computer data element format in which all records have the same length. These records allow direct access without searching or indices. See also variable-length records. HDBK-850
fixed-ratio pantograph See pantograph. HDBK-850
fixed-ratio projection printer A diapositive printer having an optical system in which a lens is placed between the negative and the diapositive plate, the object and image distances being set at nominal values according to the laws of optics, but with freedom of adjustment within narrow limits, to produce diapositives whose scale is at a predetermined ratio to the negative scale. HDBK-850
fixer network (JCS) A combination of radio or radar direction finding installations which, operating in conjunction, are capable of plotting the position relative to the ground of an aircraft in flight. HDBK-850
fixing The process of rendering a developed photographic image permanent by removing the unaffected light-sensitive material. HDBK-850
flare triangulation A method of triangulation in which simultaneous observations are made on parachute flares. This method is used for extending triangulation over lines too long to be observed by ordinary methods. HDBK-850
flash apparatus An auxiliary apparatus used in timing a pendulum during observations for intensity of gravity. HDBK-850
flash plate See calibration plate. HDBK-850
flat 1. (lithography) An assembly of photographic negatives or positives on goldenrod paper or vinyl acetate for contact exposure with a sensitized metal press plate. May contain illustrations as well as text. See also key flat; layout. 2. (photography) Lacking in contrast. 3. (optics) See optical flat. HDBK-850
flat model Any spatial model which is capable of being leveled. See also warped model. HDBK-850
flat stock 1. Charts or maps which are not folded. 2. Flat sheets of map paper as opposed to roll paper. HDBK-850
flat tint screen See dot screen. HDBK-850
flattening (of the Earth) The ratio of the difference between the equatorial and polar radii of the Earth (semimajor and semiminor axes of the spheroid) to its equatorial radius (semimajor axis). Also called compression; ellipticity of the spheroid. See also eccentricity of ellipse; eccentricity of spheroid of revolution; ellipticity of ellipse. HDBK-850
Fleet Imagery Support Terminal An imagery dissemination terminal developed by the Navy that can receive, process, and transmit imagery data to other FIST terminals, both shore-based and afloat. USIS 95
Fleet Imagery Support Terminal Version 3a A Navy secondary imagery dissemination system. USIS 95
Fleet Satellite A series of four satellites positioned to provide worldwide communication services for military users. USIS 95
Fleet Satellite Communications Four operational satellite constellation in near-equatorial orbit that provides virtually global coverage between 70 degrees north and 70 degrees south latitudes. USIS 95
flexure 1. (pendulum) The bending of a swinging pendulum, due to its lack of perfect rigidity. 2. (pendulum support) The forced movement of a pendulum support caused by the motion of the swinging pendulum. HDBK-850
flicker method 1. The alternate projection of corresponding photographic images onto a tracing table platen or projection screen, or into the optical train of a photogrammetric instrument. 2. (stereoscopy) The alternate blinking of the eyes and mentally comparing the appearance of images in a stereoscopic pair to determine differences between the two photos. HDBK-850
flight altitude The vertical distance above a given datum, usually mean sea level, of an aircraft in flight. HDBK-850
flight block An adjustable unit of photographic coverage consisting of overlapping strips of photography. A minimum size block consists of at least three overlapping flight strips. HDBK-850
flight chart See route chart, definition 2. HDBK-850
flight information and air facilities data Data concerning airfields and seaplane stations and related information required for the operation of aircraft. HDBK-850
flight line (JCS) In air photographic reconnaissance, the prescribed ground path over which an air vehicle moves during the execution of its photo mission. HDBK-850
flight line spacing The distance between adjacent tracks in a series of parallel aerial photographic flight strips. HDBK-850
flight map A map on which are indicated the proposed lines of flight and/or positions of exposure stations. Flight data are plotted on the best available map of the area. Generally used for planning purposes. HDBK-850
flight strip A succession of overlapping aerial photographs taken along a single course. Also called strip. HDBK-850
flipping The act of superimposing and comparing identical areas of two overlapping vertical photographs as an aid in laying an uncontrolled mosaic. HDBK-850
float gage Any of the tide or stream gages which permit direct reading of changes of water height by the action of a float, contained within a restricted pipe or channel, attached to a graduated tape or chain. HDBK-850
floating (cartography) The technique of making minor adjustments of detail in order to maintain their proper relative position. HDBK-850
floating lines (JCS) In photogrammetry, lines connecting the same two points of detail on each print of a stereo pair, used to determine whether or not the points are intervisible. The lines may be drawn directly onto the prints or superimposed by means of strips of transparent material. HDBK-850
floating mark (photogrammetry) A mark seen as occupying a position in the three-dimensional space formed by the stereoscopic fusion of a pair of photographs and used as a reference mark in examining or measuring the stereoscopic model. HDBK-850
flood control map A special map, or set of maps, designed for study and planning the control of areas subject to inundation. HDBK-850
flood tide The portion of the tide cycle between low water and the following high water. Also called rising tide. HDBK-850
flowline The slope extending from the heights along the neatline to the model datum, at an angle no greater than 45, to preclude forming the plastic sheet at a 90 angle at the neatline of a plastic relief map. HDBK-850
fluorescent map A map reproduced with fluorescent ink or on fluorescent paper, which enables the user to read the map in darkness under ultraviolet light. HDBK-850
flux-gate magnetometer An instrument designed to measure the Earth's magnetic field. Also called saturable reactor. HDBK-850
fluxmeter An instrument for measuring the intensity of a magnetic field. HDBK-850
fly leveling See flying levels. HDBK-850
fly-by method (surveying) A technique of determining approximate elevations where extremely rugged terrain is encountered. The principle is identical to the two-base method except the roving barometers are air transported and read in the aircraft as it passes on a level with the topographic feature whose elevation is required. HDBK-850
flying levels 1. A level line run at the close of a working day to check the results of an extended line run in one direction only. Longer sights and fewer setups are used as the purpose is to detect large mistakes. Also called fly leveling. 2. Level lines run with the engineer's ordinary leveling equipment but with a distinctly low order of accuracy. Error of closure may be perhaps one foot (or more) times the square root of the distance in miles. HDBK-850
f-number See relative aperture. HDBK-850
focal length A general term for the distance between the center, vertex, or rear node of a lens (or the vertex of a mirror) and the point at which the image of an infinitely distant object comes into critical focus. The term must be preceded by an adjective such as "equivalent" or "calibrated" to have a precise meaning. See also back focal length; calibrated focal length; effective focal length; equivalent focal length; nominal focal length. HDBK-850
focal plane (photography) The plane, perpendicular to the axis of the lens in which images of points in the object field of the lens are focused. HDBK-850
focal point See focus. HDBK-850
focal range See depth of focus. HDBK-850
focal-plane plate A glass plate set in the camera so that the surface away from the lens coincides with the focal plane. Its purpose is to position the emulsion of the film in the focal plane when the film is physically pressed into contact with the glass plate. Also called contact glass; contact plate. HDBK-850
focus The point toward which rays of light converge to form an image after passing through a lens. Also defined as the condition of sharpest imagery. Also called focal point; principal focus. See also hyperfocal distance; sidereal focus. HDBK-850
folded optics (photogrammetry) Any optical or lens system containing reflecting components which reduces the physical length of a photographic or sensing system, or changes the path of an optical axis. HDBK-850
folding vernier A single vernier so constructed and numbered that it may be read in either direction. HDBK-850
foot-meter rod A stadia rod, marked in feet and tenths on one side, and meters and hundredths on the other side, used to determine distances and elevations in one unit of measurement and to check them by readings in a different unit. HDBK-850
force function See potential. HDBK-850
Force Imagery Interpretation Unit (FIIU) The Marine Corps operating forces' principal imagery exploitation agency. One FIIU is located in the Surveillance, Reconnaissance, and Intelligence Group (SRIG) of each Marine Expeditionary Force (MEF). FIIUs plan for and provide Marine Air Ground Task Forces with imagery and imagery interpretation in support of training, planning, and combat operations. USIS 95
Force Service Support Group The combat support element of a Marine Air Ground Task Force. USIS 95
forecast collection A projection of collection (for up to 30 days into the future) operations activity based on simulations or operational plans for a specific collector and the set of all currently active requirements. USIS 95
Foreign Broadcast Information Service A system that collects and documents worldwide open-source foreign broadcast information. USIS 95
foreign instrumentation signals Emissions from radars and electronic devices. USIS 95
foreign instrumentation signals intelligence (FISINT) (DOD) Technical and intelligence information derived from the intercept of foreign electromagnetic emissions associated with the testing and operational deployment of non-US aerospace, surface, and subsurface systems. Foreign instrumentation signals intelligence is a subcategory of signals intelligence. Foreign instrumentation signals include, but are not limited to, telemetry, beaconry, electronic interrogators, and video data links. See also signals intelligence (SIGINT); telemetry intelligence (TELINT). JPUB 1-02
foreign intelligence (DOD) Information relating to capabilities, intentions, and activities of foreign powers, organizations, or persons, but not including counterintelligence, except for information on international terrorist activities. See also intelligence. JPUB 1-02
Foreign Intelligence Requirements, Categories, and Priorities Director, Central Intelligence (DCI) guidance for conducting intelligence collection and production activities during the near term; it is issued pursuant to the DCI's responsibilities set forth in Section 1.5 of Executive Order 12333. USIS 95
foreign key Inherited attributes that must migrate from the parent or generic entity to the child or category entity when a specific connection or categorization relationship exists between two entities. USIGS/CDM-A
foresight 1. An observation of the distance and direction to the next instrument station. 2. (transit traverse) A point set ahead to be used for reference when resetting the transit on line or when verifying the alignment. 3. (leveling) The reading on a rod that is held at a point whose elevation is to be determined. Also called minus sight. See also backsight. HDBK-850
forestry map A map prepared principally to show the size, density, kind, and value of trees on a given area. HDBK-850
form lines (JCS) Lines resembling contours, but representing no actual elevations, which have been sketched from visual observation or from inadequate or unreliable map sources, to show collectively the configuration of the terrain. HDBK-850
format The arrangement, order, or layout of data in or on a data medium. [IEEE 610.5] IEEE 610-1990
Formerly Restricted Data Information removed from the Restricted Data category upon a joint determination by the Department of Energy(or antecedent agencies) and DoD that such information relates primarily to the military utilization of atomic weapons and that such information can be adequately safeguarded as classified defense information. USIS 95
forming machine The equipment for forming, by heat and vacuum, preprinted plastic maps over a mold representing the terrain of the area. HDBK-850
formula for theoretical gravity A formula expressing gravity on the spheroid of reference in terms of geographic position, it being assumed that the spheroid of reference is a level surface. HDBK-850
FORSCOM Automated Intelligence Support System A secondary imagery dissemination system (SIDS) to receive, transmit, display, store, compress, decompress, annotate, adjust, pan and zoom black and white or color images. USIS 95
FORSCOM Support System The Forces Command Automated Intelligence Support System (FAISS) has been modified with an application software package to allow it to be used as a SIDS. USIS 95
FORTRAN Acronym for FORmula TRANslator, which is a high-level computer language used extensively in scientific and engineering applications. [HCI Style Guide] DISA CFS
Forward Area SID and TRAP (FAST) A U.S. Army system that serves as a deployable information analysis, data base management and data communications system to provide the tactical commander with timely IMINT, ELINT, and message information. FAST can receive, annotate, and transmit secondary imagery that is compatible with National Imagery Transmission Format systems. USIS 95
forward azimuth See azimuth, definition 1. HDBK-850
forward edge of the battle area The foremost limits of a series of areas in which ground combat units are deployed, excluding the areas in which the covering or screening forces are operating; designated to coordinate fire support, the positioning of forces, or the maneuver of units. See FLOT. USIS 95
forward lap See overlap, definition 1. HDBK-850
forward line of own troops (FLOT) A line that indicates the most forward positions of friendly forces in any kind of military operation at a specific time. The forward line of own troops normally identifies the forward location of covering and screening forces. USIS 95
forward-looking infrared (FLIR) An infrared imaging system that raster scans the scene viewed by internal means, both horizontally and vertically; it can be spacebased, airborne, seaborne, mounted on a ground vehicle, or placed at a fixed site; and its field of view is determined by the optics used, the scanning mechanism, and the dimensions of the detector array. USIS 95
found corner A term adopted by the U.S. Geological Survey to designate an existent corner of the public-land surveys which has been recovered by field investigation. HDBK-850
four-pole chain See Gunter's chain. HDBK-850
four-rod chain See Gunter's chain. HDBK-850
Fourteenth Air Force (14AF) The Fourteenth Air Force plans and executes operations for space support, force enhancement and space control and serves as the operational Air Force component to the unified United States Space Command (USSPACECOM). Fourteenth Air Force is headquartered at Vandenberg AFB, CA. SPACECOM Web Site
fourth-order traverse A survey traverse of an accuracy less than third-order traverse or which fails to meet third-order official standards. In fourth-order traverse, angles are observed with a transit or sextant or are determined graphically, and distances are measured with tape or stadia . HDBK-850
fractal A family of mathematical functions which are sometimes used to describe natural phenomena and shapes such as coastlines, mountains, river patterns, etc. HDBK-850
fractional scale See representative fraction. HDBK-850
fractional section A section containing an area appreciably different from 640 acres, usually as a result of an invasion by a segregated body of water, or by other land which cannot properly be surveyed or disposed of as part of that section. See also section. HDBK-850
fractional township A township containing less than 36 normal sections, usually because of invasion by a segregated body of water, or by other land which cannot properly be surveyed as part of that township, or by closing the public land surveys on State boundaries, or other limiting lines. Half ranges and half townships are fractional townships by definition. See also township. HDBK-850
fragmentary order An abbreviated form of an operation order, usually issued on a day-to-day basis, that eliminates the need for restating information contained in a basic operation order. It may be issued in sections. USIS 95
fragmentation The process of creating one or more small diameter point targets based on specific target elements covered by a large diameter target (LDT.) Targets are "fragged" for collection efficiency. See also point target. USIS 95
Fragmentation Schema {DII COE} The distribution design for a distributed database. The idea is that a schema (e.g., an application's view of the database) may actually require access to data that is distributed across computers or networks. DII COE IRTS
frame (JCS) In photography, any single exposure contained within a continuous sequence of photographs. HDBK-850
frame The secific local coordinate system used to define grid, raster band and pixel. ISO/TC 211
frame camera A camera in which an entire frame or format is exposed through a lens that is fixed relative to the focal plane. See also panoramic camera. HDBK-850
frames per second (fps) Frequency with which video frames appear on a monitor. Multimedia
framework {object-oriented} In object-oriented programming, a generalized subsystem design for building applications. It consists of abstract classes and their object collaboration as well as concrete classes. While object-oriented programming supports software reuse, frameworks support design reuse. Freedman 1995
framework In terms of software design, a reusable software template, or skeleton, from which key enabling and supporting services can be selected, configured and integrated with application code. See also architectural framework. OpenGIS Guide
framework of control See survey net. HDBK-850
free-air anomaly (JCS) The difference between observed gravity and theoretical gravity which has been computed for latitude and corrected for elevation of the station above or below the geoid, by application of the normal rate of change of gravity for change of elevation, as in free air. Also called Faye anomaly. HDBK-850
free-air correction Correction factor, usually expressed as milligals per meter, which is applied to observed gravity to reduce the value to sea level. Also called Faye correction. HDBK-850
free-swinging pendulum A pendulum moving wholly under the influence of gravity and an initial momentum imparted to it by mechanical or other means. In gravity work, the initial momentum may be imparted by drawing the pendulum slightly out of plumb and then releasing it. HDBK-850
frequency division multiple access The use of frequency division to provide multiple and simultaneous transmissions to a single transponder. USIS 95
frequency division multiplex A device or process for transmitting two or more signals over a common path by sending each one over a different frequency band. USIS 95
frequency modulation The form of angle modulation in which the instantaneous frequency of a sine wave carrier is caused to depart from the carrier frequency by an amount proportional to the instantaneous value of the modulating signal. USIS 95
Fresnel lens A lens which consists of a thin stepped disc with each step having the curvature of a much thicker lens. A similar design would be the roof of a factory that looks like the teeth of a saw. This pattern, embossed in plastic, is used to distribute image (or light) brightness over a given area. HDBK-850
frilling The separation, along the edges, of the photographic emulsion from its base. HDBK-850
from object type An object type associated with another object type that is regarded as a to object type. CEN/TC 287
front element See lens element. HDBK-850
front focal distance The distance measured from the vertex of the front surface of the lens to the front focal point. HDBK-850
front nodal point See nodal point, definition 1. HDBK-850
front surface mirror An optical mirror on which the reflecting surface is applied to the front surface of the mirror instead of to the back; i.e., to the first surface of incidence. HDBK-850
full frame image The image record of imaging operations in original or altered (enlarged or reduced) format with titling data, marginal data, or ephemeris data. An image is less than full frame when this data has been excised and the outer edges of the image do not show. USIS 95
Full Operational Capability (FOC) 1. At the system level, FOC is the point at which a fielded system fully meets the technical and operational specifications of the requirements documentation. FOC for a system may also be declared with exceptions agreed to by the Program Manager, the User, and the O&M activity. 2. At the site level, FOC is the point at which that portion of the system at that site fully meets the technical and operational specifications of the requirements documents. FOC for the site may also be declared with exceptions agreed to by the Program Manager, the site manager, and the O&M activity. [DISA/D4] DISA CFS
full topology A planar surface which is partitioned by a set of mutually exclusive and collectively exhaustive faces. See also Level 3 topology. ISO/TC 211
function A process that performs a single operation and may return one or more values. CEN/TC 287
function 1. A defined objective or characteristic action of a system or component. For example, a system may have inventory control as its primary function. [IEEE 610.12] 2. A software module that performs a specific action, is invoked by the appearance of its name in an expression, may receive input values, and returns a single value. [IEEE 610.12] 3. A mathematical entity whose value is uniquely determined by the value of one or more independent variables. [IEEE 610.2] IEEE 610-1990
function Appropriate or assigned duties, responsibilities, missions, tasks, powers, or duties of an individual, office, or organization. A functional area is generally the responsibility of a Principal Staff Assistant (PSA) (e.g., personnel) and can be composed of one or more functional activities (e.g., recruiting), each consisting of one or more functional processes (e.g., interviews). JPUB 1-02
Functional Activity Program Manager (FAPM) FAPMs are designated by Principal Staff Assistants (PSAs) and are accountable for executing the functional management process. Supported by functional representatives from the DOD Components, FAPMs develop functional architectures and strategic plans, and establish the process, data, and information system baselines to support functional activities within the functional area. [DOD 8020.1-M, Ch 1 B(2)]. DISA CFS
Functional Architecture The framework for developing applications and defining their interrelationships in support of an organization's information architecture. It identifies the major functions or processes an organization performs and their operational interrelationships. [DOD 5000.11-M] DISA CFS
functional area A major area of related activity (e.g., Ballistic Missle Defense, Logistics, or C2 support). (DDDS 4198(A)) C4ISR AF
functional area A range of subject matter grouped under a single heading because of its similarity in use or genesis. [DODD 8320.1] DISA CFS
functional command A command that has worldwide responsibilities. Operations are limited to one of the four specific functional areas (strategic, space, transportation, and special operations). A corresponding Command has been designated for each of the functional areas (i.e., USSTRATCOM, USSPACECOM, USTRANSCOM and USSOCOM). USIS 95
Functional Data Administrator (FDAd) OSD PSAs exercise or designate functional data administrators to perform data administrator responsibilities to support execution of the functional management process, and to function within the scope of their overall assigned responsibilities. [DODD 8320.1 and DOD 8020.1-M, Appendix A]. DISA CFS
Functional Economic Analysis (FEA) A structured proposal that serves as the principal part of a decision package for enterprise (individual, office, organization) leadership. It includes an analysis of functional process needs or problems; proposed solutions, assumptions, and constraints; alternatives; life-cycle costs; benefits and/or cost analysis; and investment risk analysis. It is consistent with, and amplifies, existing DOD economic analysis policy. [DODI 7041.3, DODD 8000.1, and DOD 8020.1-M, Appendix H] DISA CFS
functional requirement A requirement that specifies a function that a system or system component must be able to perform. [IEEE 610.12] IEEE 610-1990
functions {ODP} Management functions: node management function, object management function, cluster management function, capsule management function Coordination functions: event notification function, checkpointing and recovery function, deactivation and reactivation function, group function, replication function, migration function, engineering interface reference tracking function, transaction function. Repository functions: storage function, information organization function, relocation function, type repository function, trading function. Security functions: access control function, security audit function, authentication function, integrity function, confidentiality function, non-repudiation function, key management function. RM-ODP
fundamental circle See primary great circle. HDBK-850
fundamental star places The apparent right ascensions and declinations of standard comparison stars obtained by leading observatories and published annually. HDBK-850
fundamental tables, deformation of the geoid and its effect on gravity Tables giving the deformation of the geoid and its effect on gravity, computed for masses of unit density extending to various distances above and below the surface of the geoid. Fundamental tables serve as the basis for the preparation of special tables corresponding to particular assumptions respecting density, isostasy, etc. HDBK-850
funtional component A structural element in an architectural model. IEEE 1471
fusion The blending of intelligence information from multiple sources to produce a single intelligence product. USIS 95
Future National Intelligence Requirement(s) The Director of Central Intelligence (DCI) guidance for planning intelligence collection and production resource need for the period 10 years out and beyond. USIS 95

Last Updated by Mark Owens 17 February 1999.