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Term Definition/Description Source
Oak Ridge National Laboratory (ORNL) ORNL is a multiprogram science and technology laboratory managed for the United States Department of Energy (DoE) by Lockheed-Martin Energy Research Corporation. ORNL conducts basic and applied research and development to create scientific knowledge and technological solutions that streng'hen the nation's leadership in key areas of science; increase the availability of clean, abundant energy; restore and protect the environment; and contribute to national security. ORNL also performs other work for the DoE, including isotope production, information management, and technical program management, and provides research and technical assistance to other organizations. ORNL is located in Oak Ridge, TN. ORNL Web Site
object A combination of state and a set of methods that explicitly embodies an abstraction characterized by the behavior of relevant requests. An object is an instance of an implementation and an interface. An object models a real-world entity, and it is implemented as a computational entity that encapsulates state and operations (internally implemented as data and methods) and responds to request or services. CORBA 2.2
object A model of an entity. An object is characterized by its behavior and, dually, by its state. An object is distinct from any other object. An object is encapsulated, i.e. any change in its state can only occur as a result of an internal action or as a result of an interaction with its environment. An object interacts with its environment at its interaction points. RM-ODP
object (instance, software object) An object is a software entity that has state, behavior, and identity; the structure and behavior of similar objects are defined in their common class; the terms instance and object are interchangeable. ITSG Vol. 1
object adapter The ORB [Object Request Broker]component which provides object reference, activation, and state related services to an object implementation. There may be different adapters provided for different kinds of implementations. CORBA 2.2
object creation An event that causes the existence of an object that is distinct from any other object. CORBA 2.2
object destruction An event that causes an object to cease to exist. CORBA 2.2
object implementation Same as implementation. CORBA 2.2
Object Management Group (OMG) With a membership of over 800 software vendors, software developers and end users, the OMG is establishing the Common Object Request Broker Architecture (CORBA) through its worldwide standard specifications. Establish'd in 1989, OMG's mission is to promote the theory and practice of object technology for the development of distributed computing systems. The goal is to provide a common architectural framework for object oriented applications based on widely available interface specifications. OMG is headquartered in Framingham, MA. OMG Web Site
object model A specification of the objects intrinsic to a given system, including a description of the object characteristics (attributes) and a description of the static and dynamic relationships that exist between objects. (HLA Glossary, www.dmso.mil/projects/hla/docslib/hlagloss.html) JTA 2.0
object oriented A design and programming methodology that seeks to mimic the way we form models of the world, and embodies three main properties, e.g., encapsulation, inheritance, and polymorphism. HDBK-850
object reference A value that unambiguously identifies an object. Object references are never reused to identify another object. CORBA 2.2
object request broker (ORB) Provides the means by which clients make and receive requests and responses. See also Common Object Request Broker Architecture (CORBA). CORBA 2.2
object request broker (ORB) core The ORB component which moves a request from a client to the appropriate adapter for the target object. CORBA 2.2
object type A class of objects having common characteristics. CEN/TC 287
objective architecture (TAP) A C4ISR Architecture description of the desired United States Imagery and Geospatial Information System (USIGS) "end-state". NIMA/AR
objective lens In telescopes and microscopes, the optical component which receives light from the object and forms the first or primary image. In a camera, the image formed by the objective lens is the final image. In a telescope or microscope used visually, the image formed by the objective lens is magnified by the eyepiece. HDBK-850
oblate ellipsoid of rotation An ellipsoid of rotation, the shorter axis of which is the axis of rotation. HDBK-850
obligation A prescription that particular behavior is required. An obligation is fulfilled by the occurrence of the prescribed behavior. RM-ODP
oblique air photograph (JCS) An air photograph taken with the camera axis directed between the horizontal and vertical planes. Commonly referred to as an oblique: (1) high oblique-one in which the apparent horizon appears; and (2) low oblique-one in which the apparent horizon does not appear. HDBK-850
oblique ascension The arc of the celestial equator, or the angle at the celestial pole, between the hour circle of the vernal equinox and the hour circle through the intersection of the celestial equator and the eastern horizon at the instant a point on the oblique sphere rises, measured eastward from the hour circle of the vernal equinox through 24 hours. HDBK-850
oblique chart A chart on an oblique map projection. HDBK-850
oblique coordinates Magnitudes defining a point relative to two intersecting nonperpendicular lines, called axes. HDBK-850
oblique cylindrical orthomorphic map projection See oblique Mercator projection. HDBK-850
oblique equator A great circle the plane of which is perpendicular to the axis of an oblique projection. HDBK-850
oblique graticule A fictitious graticule based upon an oblique map projection. HDBK-850
oblique latitude Angular distance from an oblique equator. See also fictitious latitude. HDBK-850
oblique longitude Angular distance between a prime oblique meridian and any given oblique meridian. See also fictitious longitude. HDBK-850
oblique map projection A map projection with an axis inclined at an angle between 0 and 90. HDBK-850
oblique Mercator projection A conformal cylindrical map projection in which points on the surface of a sphere or ellipsoid, such as the Earth, are conceived as developed by Mercator principles on a cylindrical tangent along an oblique great circle. Also called oblique cylindrical orthomorphic projection. HDBK-850
oblique meridian A great circle perpendicular to an oblique equator. The reference oblique meridian is called prime oblique meridian. See also fictitious meridian. HDBK-850
oblique parallel A circle or line parallel to an oblique equator, connecting all points of equal oblique latitude. See also fictitious parallel. HDBK-850
oblique plotting instrument An instrument for plotting from oblique photographs. HDBK-850
oblique pole One of the two points 90 from an oblique equator. HDBK-850
oblique rhumb line 1. A line making the same oblique angle with all fictitious meridians of an oblique Mercator projection. Oblique parallels and meridians may be considered special cases of the oblique rhumb line. 2. Any rhumb line, real or fictitious, making an oblique angle with its meridians. In this sense the expression is used to distinguish such a rhumb line from parallels and meridians, real or fictitious, which may be included in the expression rhumb line. See also fictitious rhumb line. HDBK-850
oblique sketchmaster A type of sketch-master in which oblique photographs are utilized. HDBK-850
oblique sphere The celestial sphere as it appears to an observer between the Equator and the pole, where celestial bodies appear to rise obliquely to the horizon. HDBK-850
obliquity An image taken with the sensor directed between the horizontal and vertical planes can result in an image commonly referred to as an oblique. An oblique image can be either a high or low oblique. A high oblique image is one in which the apparent horizon appears. The apparent horizon does not appear in a low oblique. The characteristic of obliquity portrays the terrain and objects at such an angle that details are either emphasized or degraded depending on the scale of the image and the position of the object of interest. USIS 95
obliquity angle The angle formed from nadir-to-imaging-vehicle-to-ground point angle. USIS 95
obliquity of the ecliptic The acute angle between the plane of the ecliptic (the plane of the Earth's orbit) and the plane of the celestial equator. HDBK-850
obliterated corner An obliterated corner is one at whose point there are no remaining traces of the monument or its accessories, but whose location has been perpetuated, or the point for which may be recovered beyond reasonable doubt, by the acts and testimony of the intersected landowners, competent surveyors, or other qualified local authorities, or witnesses, or by some acceptable record evidence. HDBK-850
observables Those activities or objects that are expected to be present (or absent) at a target locale and may be detected or monitored by imagery. USIS 95
observation See observed value. HDBK-850
observation equation An adjustment equation wherein variables representing corrections to approximations of the unknown parameters, as well as variables representing adjustments to the observations, remain in the equations. A least squares adjustment employing this type of equations is said to be by the observation equations method, or variation of parameters method, as opposed to the condition equations method. HDBK-850
observed altitude Corrected sextant altitude; angular distance to the center of a celestial body above the horizon, corrected for instrumental errors, personal error, dip, refraction, and semidiameter and parallax if necessary. See also true altitude. HDBK-850
observed angle An angle obtained by direct instrumental observation. A measured angle which has been corrected for local conditions only at the point of observation, is considered an observed angle. HDBK-850
observed gravity The value of gravity at a station as determined from a gravity meter, a pendulum, or an instrument timing free falling bodies. The gravity obtained is either relative or absolute according to the apparatus used to make the measurements. HDBK-850
observed gravity anomaly See gravity anomaly. HDBK-850
observed value A value of a quantity that is obtained by instrumental measurement of the quantity. The term observed value is often applied to the value of a quantity derived from instrumental measurement after corrections have been applied for systematic errors by some method of adjustment. HDBK-850
obsolete chart A chart which does not contain the latest navigational information. HDBK-850
occultation 1. (astronomy) The disappearance of a celestial body behind another body of larger apparent size. When the Moon passes between the observer and a star, the star is said to be occulted. 2. (surveying) Name applied to a geodetic survey technique which employs the principle of occultation where repeated observations are made on an unknown position, accurately timed with similar observations at another unknown station, and mathematically reducing these data to determine the exact geodetic position of the unknown stations. See also star occultation method. HDBK-850
occupy (surveying) To set a surveying instrument over a point for the purpose of making observations. HDBK-850
occurrences The estimated number of instances or amount of data of objects of a certain object type in a dataset. CEN/TC 287
Ocean Surveillance Information System Located at fleet ocean surveillance information facilities and centers (Fleet Ocean Surveillance Information Facility and Fleet Ocean Surveillance Information Center). A fusion system for all-source intelligence data. USIS 95
oceanographic station An observation point in ocean from which oceanographic observations are taken. HDBK-850
oceanographic survey A study or examination of conditions in the ocean or any part of it, with reference to animal or plant life, chemical elements present, temperature gradients, etc. Also called marine survey. HDBK-850
oceanography 1. The study of the sea, embracing and integrating all knowledge pertaining to the sea and its physical boundaries, the chemistry and physics of sea water, and marine biology. HDBK-850
oceanology See oceanography. HDBK-850
octant A type of sextant having a range of 90 and an arc of 45. HDBK-850
ocular micrometer A filar micrometer so placed that its wire moves in the principal focal plane of a telescope Also called eyepiece micrometer. HDBK-850
odograph A mechanical instrument containing a distance measuring element which is moved or turned by an amount proportional to the actual distance traveled; a compass element which provides a fixed reference direction; and an integrator which provides for the resolution of the direction of motion into components and for the summation or integration of the distance components. HDBK-850
off soundings Any area where the depth of water cannot be measured by a sounding lead, generally considered to be beyond the 100-fathom line. Opposite of on soundings. HDBK-850
office computations Computations based on field measurements, including all calculations relative to the reduction of field survey notes to graphic form for any type of survey or for the continuation of field work. HDBK-850
Office of Primary Responsibility (OPR) Denotes a point of authority for a program, system, etc. USIS 95
off-line Transmission of information between a computer and a peripheral unit before or after, but not during processing, in contrast to on-line processing. HDBK-850
off-line data Digital data that are accessible through standard discovery mechanisms that require a human operator to retrieve the media on which the data resides. Response times range from several minutes to one hour. In this case, storage media are located close to the operator (e.g. in the same or next room). See also on-line data, near on-line data and far off-line data. USIS 95
offset 1. (cartography) In projection construction, that small distance added to the length of the meridians on each side of the central meridian in order to determine the top latitude of the constructed chart. 2. (surveying) A short line perpendicular to a surveyed line, measured to a line or point for which data are desired, thus locating the second line or point with reference to the first or surveyed line. An offset is also a job in a survey or other line, the line having approximately the same direction both before and after passing the jog. Offsets are measured from a surveyed line, or lines to the edges of an irregular-shaped body of water, or to any irregular line which it is desired to locate. 3. (printing) See offset lithography. HDBK-850
offset line A supplementary line close to and roughly parallel with a main line, which is referred by measured offsets. Where the line for such data are desired is in such position that it is difficult to measure over it, the required data are obtained by running an offset line in a convenient location and measuring offsets from it to salient points on the other line. HDBK-850
offset lithography An indirect method of printing whereby the ink image is transferred from the press plate to an intermediate surface of a rubber blanket, and from that to the paper or other stock. Also called offset; offset printing. See also lithography; photolithography. HDBK-850
offset press A press which contains an extra cylinder, rubber covered, upon which the image is printed first and then reprinted or "offset," from this cylinder onto the paper. HDBK-850
offset printing See offset lithography. HDBK-850
OK sheet The first press impression from each color, or color combination, approved for accuracy of register and color. HDBK-850
Omega A long-range hyperbolic navigation system designed to provide worldwide coverage for navigation. HDBK-850
omnidirectional radar prediction A radar prediction which is intended to be valid from any direction of approach. The Radar Significance Analysis Code on the Series 200 Air Target Chart is an example of omnidirectional radar prediction. Each coded area represents an analysis of relative radar intensity from all directions. HDBK-850
omnigain radar prediction A radar prediction containing some information about all radar responsive features within the predicted area. This is accomplished by predicting all significant radar returns in relative intensities based on the predicted probability of the return remaining on the radarscope at decreased gain. Generally, the more intense the return appears on the prediction, the more likely it will remain on the radarscope as the gain is decreased. HDBK-850
on soundings Any area where the depth of water can be measured by a sounding lead, generally considered to be within the 100-fathom line. Opposite of off soundings. HDBK-850
onboard processor A component that converts data prior to being down-linked. USIS 95
on-demand collection The ability to position appropriate collectors at the needed time in response to an unexpected or high-interest event. USIS 95
one-projector method See one-swing method. HDBK-850
one-swing method The technique employed in relative orientation for clearing y-parallax by maintaining one projector of a pair in a fixed position and making all adjustments with the second projector in relationship to the first. Also called one-projector method; single-projector method. Y-swing method; HDBK-850
one-to-one (1:1) copy See contact size. HDBK-850
one-way request A request where the client does not wait for completion of the request, nor does it intend to accept results. Contrast with deferred synchronous request and synchronous request. CORBA 2.2
online A state (referring to equipment such as plotters, printers, and digitizers) of being turned on and actively communicating with a computer or computer network. OpenGIS Guide
on-line Transmission of information between a computer and a terminal or display device while processing is occurring, in contrast to off-line processing. HDBK-850
on-line data Digital data with response times measured in seconds that are electronically accessible using standard discovery mechanisms. This data is kept on storage devices that provide the fastest response time to users' requests. Examples include solid-state memory and rotting magnetic and optical disks. See also near on-line data, off-line data and far off-line data. USIS 95
On-Site Inspection Agency (OSIA) OSIA was a joint-service Department of Defense organization responsible for implementing inspection, escort and monitoring activities associated with a number of international arms control treaties and confidence-building agreements. Under the auspices of the Defense Reform Initiative, OSIA merged, on October 1, 1998, with the Defense Special Weapons Agency (DSWA), the Defense Technology Security Administration (DTSA), and some program functions of the Assistant to the Secretary of Defense for Nuclear, Chemical and Biological Defense Program to form the Defense Threat Reduction Agency (DTRA). OSIA Web Site
opacity See density, definition 1. HDBK-850
opaque 1. Not transmitting light. 2. Not transmitting the particular wavelengths (which may or may not be visible) which affect given photosensitive materials. Thus, a substance may be opaque to some colors and not to others. It may be visually transparent, yet actinically opaque. 3. A material applied to areas of a negative to make it opaque in those areas. 4. To apply a material or blockout. HDBK-850
open end traverse See open traverse. HDBK-850
Open Geodata Interoperability Specification (OpenGIS® ) See OpenGIS® Specification. OGC Web Site
Open Geodata Model (OGM) That part of the OpenGIS Abstract Specification which defines a general and common set of basic geographic information types that can be used to model the geodata needs of more specific application domains, using object-based and/or conventional programming methods. OpenGIS Guide
open geographic data service The standard method for sharing geographic data between applications and systems. CEN/TC 287
Open GIS Consortium, Inc. (OGC) The OGC is a unique membership organization dedicated to the development of open system approaches to geoprocessing. The OGC is creating the OpenGIS® Specification, an unprecedented software specification which is a necessary prerequisite for geoprocessing interoperability. OGC Web Site
Open Group See The Open Group. Open Group Web Site
open network A network that can communicate with any system component (peripherals, computers, or other networks) implemented to the international standard (without special protocol conversions, such as gateways). TAFIM 3.0
Open Software Foundation (OSF) Now called The Open Group. Open Group Web Site
open specifications Specifications that are maintained by an organization that uses an open, public consensus process to accommodate new technologies and user requirements over time. IEEE P1003.0
open system A system that implements sufficient open specifications or standards for interfaces, services, and supporting formats to enable properly engineered application software
- To be ported with minimal changes across a wide range of systems from one or more suppliers
- To interoperate with other applications on local and remote systems
- To interact with people in a style that facilitates user portability
IEEE P1003.0
open system A system that implements sufficient open specifications for interfaces, services, and supporting formats to enable properly engineered components to be utilized across a wide range of systems with minimal changes, to interoperate with other components on local and remote systems, and to interact with users in a style that facilitates portability. An open system is characterized by e following:
- Well defined, widely used, non-proprietary interfaces/otocols, and
- Use of standards which are developed/adopted by industrially recognized standards bodies, and
- Definition of all aspects of system interfaces to facilitate new or additional systems capabilities for a wide range of appcations, and
- Explicit provision for expansion or upgrading through the incorporation of additional or higher performance elements with minimal impact on the system.
(IEEE POSIX 1003.0/D15 as modified by the Tri-Service Open Systems Architecture Working Group)
JTA 2.0
open system application program interface A combination of standards-based interfaces specifying a complete interface between an application program and the underlying application platform. IEEE P1003.0
Open System Environment (OSE) A comprehensive set of interfaces, services, and supporting formats, plus user aspects for interoperability or for portability of applications, data, or people, as specified by information technology standards and profiles. IEEE P1003.0
open systems approach An open systems approach is a business approach that emphasizes commercially supported practices, products, specifications and standards. The approach defines, documents, and maintains a system technical architecture that depicts the lowest level of system configuration control. This architecture clearly identifies all the performance characteristics of the system including those that will be accomplished with an implementation that references open standards and specifications. (OS-JTF) JTA 2.0
open systems deployment plan A general plan for Service/Agency implementation of open systems providing the road map for fielding of open systems in weapon systems and guidance necessary for the Service/Agency weapon system acquisition community to follow an open systems approach and to transition to open system implementations. DODI 4630.8
Open Systems Interconnection (OSI) A set of standards that, when implemented, let different computer systems communicate with each other. TAFIM 3.0
Open Systems Interconnection (OSI) Reference Model The seven-layer model, defined by the ISO, that provides the framework for building an open network. The seven layers, ranging from highest to lowest, are: application layer, presentation layer, session layer, transport layer, network layer, data link layer, and physical layer. TAFIM 3.0
open traverse A survey traverse which begins from a station of known or adopted position, but does not end upon a known or adopted station. Also called open end traverse. HDBK-850
open window process (cartography) A method of preparing color separation negatives or positives by peeling an opaque stratum from its base in the desired areas. It is normally used for preparing large areas covered by vegetation or open water. See also mask, definition 2. HDBK-850
OpenGIS Abstract Specification That part of the OpenGIS Specification created by the OGC Technical Committee to provide a high level description of the functionality to be provided in the OpenGIS Implementation Specification. OpenGIS Guide
OpenGIS Application An application that references the Open Geodata Model, OpenGIS features, and OpenGIS services. OpenGIS Guide
OpenGIS Implementation Specification Detailed software specifications for implementing parts of the OpenGIS Abstract Specification on particular distributed computing platforms such as OLE/COM and CORBA. OpenGIS Guide
OpenGIS Service A software component providing object management, access, manipulation, interchange, or human-technology services for OpenGIS features. OpenGIS Guide
OpenGIS Specification Being created by the Open GIS Consortium, Inc. (OGC), it will become the basis for interoperable geoprocessing among network-based resources which vendors and integrators use to create solutions for users. Software interfaces based on the OpenGIS® Specification enables integrators to build task-specific geoprocessing functions into any information system, bringing new capabilities to a wide variety of user environments. OGC Web Site
open-source intelligence (OSINT) (DOD) Information of potential intelligence value that is available to the general public. See also intelligence. JPUB 1-02
operating system A collection of software, firmware, and hardware elements that controls the execution of computer programs and provides such services as computer resource allocation, job control, input/output control, and file management in a computer system. [IEEE 610.12] IEEE 610-1990
Operating System Service {DoD TRM} A core service of the Platform entity of the Technical Reference Model that is needed to operate and administer the application platform and provide an interface between the application software and the platform (e.g., file management, input/output, print spoolers). TAFIM 3.0
operating system software Application-independent software that supports the running of application software and manages the resources of the application platform. IEEE P1003.0
operation A service that can be requested. An operation has an associated signature, which may restrict which actual parameters are valid. CORBA 2.2
operation A change in the value of one or more feature attributes that occurs over a period of time. ISO/TC 211
operation The actual imaging of a target. USIS 95
operation map (JCS) A map showing the location and strength of friendly forces involved in an operation It may indicate predicted movement and location of enemy forces. HDBK-850
operation name A name used in a request to identify an operation. CORBA 2.2
operational architecture view The operational architecture view is a description of the tasks and activities, operational elements, and information flows required to accomplish or support a military operation. It contains descriptions (often graphical) of the operational elements, assigned tasks and activities, and information flows required to support the warfighter. It defines the type of information, the frequency of exchange, which tasks and activities are supported by the information exchanges, and the nature of information exchanges in detail sufficient to ascertain specific requirements. C4ISR AF
operational facility (OPFAC) (TAP) An organizational node. NIMA/AR
operational grid A grid in current operational use. Generally this would be the preferred grid but could be a previously prescribed grid. HDBK-850
operational imagery Imagery used for the planning and execution of all types of operations. An input to operational intelligence. USIS 95
operational intelligence (OPINTEL) (DOD) Intelligence that is required for planning and conducting campaigns and major operations to accomplish strategic objectives within theaters or areas of operations. See also intelligence; tactical intelligence (TACINTEL); strategic intelligence. JPUB 1-02
Operational Navigation Chart (ONC) The standard worldwide small-scale (1:1,000,000) aeronautical chart series. It contains cartographic data with an aeronautical overprint depicting obstructions, aerodromes, etc., designed for medium altitude high-speed visual and radar navigation. Also used for mission planning/analysis and intelligence briefings. HDBK-850
Operational Node Connectivity Description A product depicting the operational nodes and elements, the needlines between them, and the characteristics of the information exchanged. The information illustrated in this description can be used to make decisions about which systems are needed to satisfy business needs of an organization or functional area. C4ISR AF
operational requirement See military requirement. JPUB 1-02
Operational Requirements Document (ORD) A formatted statement containing operational performance parameters for a proposed concept or system. Each concept proposed at AcquisiIion Milestone I for continued evaluation in later phases will be described in an initial ORD In terms that define the system capabilities needed to satisfy a mission need. DoDD 5000.1
operational units The units or organizations below the component level of Unified Commands (i.e., wings, squadrons, corps, battalions, and battle groups.) USIS 95
operations security A process of analyzing friendly actions attendant to military operations and other activities to: 1. Identify those actions that can be observed by adversary intelligence systems. 2. Determine indicators hostile intelligence systems might obtain that could be interpreted or pieced together to derive critical information in time to be useful to adversaries. 3. Select and execute measures that eliminate or reduce to an acceptable level the vulnerabilities of friendly actions to adversary exploitation. USIS 95
operator a combination of a domain set, a range set, and a function that maps each element of the domain to some corresponding element of the range. NOTE - Operators are written with a functional notation as F:XÆY, (read "the function F mapping X into Y") and y=F(x) (read "y equals F evaluated at x"). Operators on Cartesian products (see below) are often written without the "< >" as in F:ABÆY (read "the function F mapping the product of A and B into Y") as y=F(a,b) (read "y equals F evaluated at the pair x, and y"). A spatial operator is one which has at least one spatial component in either its domain set or range set or both. The spatial domains are described below. An operator algebra is a set of operators, their corresponding domains, and a set of algebraic rules that defines their behaviour under functional compositions. ISO/TC 211
opposition 1. The situation of two celestial bodies having either celestial longitudes or sidereal hour angles differing by 180. The term is usually used only in relation to the position of a planet or moon from the Sun. 2. The situation of two periodic quantities differing by half a cycle. HDBK-850
optical Sometimes called "visible." Refers to the traditional type of sensors using the visible portion of the electromagnetic spectrum and recorded on black and white photographic film. USIS 95
optical axis (JCS) In a lens element, the straight line which passes through the centers of curvature of the lens surfaces. In an optical system, the line formed by the coinciding principal axes of the series of optical elements. Also called axis of lens; lens axis; principal axis. HDBK-850
optical base-line measuring apparatus A base apparatus composed of bars whose lengths are defined by distances between lines at or near their ends, which are observed by suitably mounted and adjusted microscopes. In using any optical baseline measuring apparatus, the positions of the bars are controlled by microscopes on stable support, whose reticle lines may be brought into coincidence with the fiducial marks on the bars, either by adjusting a bar or a microscope. HDBK-850
optical center The point of intersection of lines which represent within the lens those rays whose emergent directions are parallel to their respective incident directions. This point lies on the optical axis. An oblique ray, even if it passes through this point, undergoes a longitudinal displacement increasing with the thickness of the lens. HDBK-850
Optical Character Recognition (OCR) The analysis and translation of a graphic representation of text into a coded form such as ASCII or EBCDIC. [HCI Style Guide] DISA CFS
optical correlation The process of electronically relating a stored photographic film chip of a geographic area with a realtime optical image acquired by photographic or television sensors. It is used to provide positioning information to correct or check air navigation and guidance systems. HDBK-850
optical density A common logarithm of reciprocal of transmittance. HDBK-850
optical flat A surface, usually of glass, ground and polished plane within a fraction of a wavelength of light. An optical element or glass blank with an optical flat is used to test the flatness of other surfaces. Also called flat; optical plane. HDBK-850
optical parallax See instrument parallax, definition 1. HDBK-850
optical path The path followed by a ray of light through an optical system. HDBK-850
optical plane See optical flat. HDBK-850
optical plummet See vertical collimator. HDBK-850
optical rectification The process of projecting the image of a tilted aerial photograph onto a horizontal reference plane to eliminate the image displacements caused by tilt of the aerial camera at the time of exposure. HDBK-850
optical square A small hand instrument used in setting off a right angle. One form of optical square uses two plane mirrors placed at an angle of 45 to each other. In use, one object is sighted direct, and another object is so placed that its twice-reflected image appears directly in line with the first object. The lines to the point of observation from the two observed objects will then meet in a right angle. In another form of optical square, a single plane mirror is so placed that it makes an angle of 45 with a sighting line; one object is sighted direct, and the other so placed that its reflected image is seen also in the sighting line. HDBK-850
optical system All the parts of a compound lens and accessory optical parts which are designed to contribute to the formation of an image on a photographic emulsion, or of a visual image, or of an image on a projection screen. HDBK-850
optical vernier A microscope with vernier lines ruled on a glass slide placed in the focal plane common to the objective and the eyepiece, where it is compared with the image of the graduated circle. HDBK-850
optical wedge See wedge. HDBK-850
optical-mechanical scanner A system utilizing a rotating mirror and a detector in conjunction with lenses and prisms to record reflected and/or emitted electromagnetic energy in a scanning mode along the flight path. HDBK-850
optical-projection instruments A class of instruments which provide projected images of photographic prints or other opaque material superimposed on a map or map manuscript. Often used for transferring detail from near-vertical photographs or other source material. HDBK-850
optimum ground elevation (photogrammetry) The elevation of an assumed horizontal surface in the area photographed that would be projected at the optimum distance in the plotting instrument. HDBK-850
option A portion of the specification within a standard that is not required to be present in a conforming implementation. See also conditional feature. (IEEE Std. 1003.3-1991) ITSG Vol. 1
orbit The path of a body or particle under the influence of a gravitational or other force. For example, the orbit of a celestial body or satellite is its path relative to another body around which it revolves. The term orbit is commonly used to designate a closed path. See also central force orbit; intermediate orbit; nominal orbit; normal orbit; osculating orbit; perturbed orbit; polar orbit; stationary orbit; two-body orbit. HDBK-850
orbital altitude The mean altitude above the surface of the parent body of the orbit of a satellite. HDBK-850
orbital elements A set of six parameters defining the orbit of a body attracted by a central force. HDBK-850
orbital inclination The direction that the path of an orbiting body takes. In the case of an Earth satellite, this path may be defined by the angle of inclination of the path to the Equator. HDBK-850
orbital mode A method for determining the position of an unknown station position when the unknown position cannot be viewed simultaneously with known positions. The arc of the satellite orbit is extrapolated from the ephemeris of the satellite determined by the known stations which permits the determination of the position of the unknown station dependent completely 'n the satellite's orbital parameters. HDBK-850
orbital motion Continuous motion in a closed path about and as a direct result of a source of gravitational attraction. HDBK-850
orbital path One of the tracks of a primary body's surface traced by a satellite that orbits about it several times in a direction other than normal to the primary body's axis of rotation. Each track is displaced in a direction opposite and by an amount equal to the degrees of rotation between each satellite orbit. HDBK-850
orbital period The interval between successive passages of a satellite through the same point in its orbit. Also called period of satellite. HDBK-850
orbital period The time, expressed in minutes and seconds, for one complete revolution of a satellite around the Earth (that is, the time between two successive crossings of the ascending node). USIS 95
orbital plane The plane of the ellipse defined by a central force orbit. HDBK-850
orbital velocity The velocity of an Earth satellite or other orbiting body at any given point in its orbit. HDBK-850
order (A&D LDM Entity: "ORDER") An official request for products or information. A&D LDM
order of battle The identification, strength, command structure, and disposition of the personnel, units, and equipment of any military force. USIS 95
ordinal reference system A temporal reference system composed of a set of named intervals ordered in time. NOTE - The length of each interval, and the instant of time at which each begins and ends may be unknown or indefinite. ISO/TC 211
ordinal time scale A scale for the measurement of time which provides a basis for describing only the relative position of a temporal primitive. ISO/TC 211
ordinates In a system of rectangular or oblique coordinates, the linear distance of a point measured from the horizontal or x-axis, and parallel to the y-axis. Also called total latitudes; y-coordinate. HDBK-850
organization (UCDM Entity: "ORGANIZATION") An administrative structure with a mission. USIGS/CDM-A
Organizational Development A process of planned systematic change capitalizing and optimizing the human resource element, making organizations better able to attain the short- and long-term objectives. [DISA QCS] DISA CFS
Organizational Message A message that includes command and control traffic and messages exchanged between organizational elements. These messages require release by the sending organizational and distribution determination by the receiving organization. Due to their official and sometimes critical nature, such messages impose operational requirements on the communications systems for capabilities such as nonroutine precedence, guaranteed timely delivery, high availability and reliability, and a specified level of survivability. [DISA/D2] DISA CFS
orientation 1. The act of establishing correct relationship in direction with reference to the points of the compass. 2. The state of being in correct relationship in direction with reference to the points of the compass. 3. A map is in orientation when the map symbols are parallel with their corresponding ground feature'. 4. A surveyor's transit is in orientation if the horizontal circle reads 0 when the line of collimation is parallel to the direction it had at an earlier (initial) position of the instrument, or to a standard line of reference. If the line of reference is a meridian, the circle will show azimuths referred to that meridian. 5. A photograph is in orientation when it correctly presents the perspective view of the ground or when images on the photograph appear in the same direction from the point of observation as do the corresponding map symbols. 6. Photogrammetric orientation is the recreation of natural terrain features at a miniature scale by the optical projection of overlapping photographs. The model is formed when all corresponding light rays from the two projectors intersect in space. See also absolute orientation; aeroleveling; astrogeodetic datum orientation; basal orientation; empirical orientation; exterior orientation; gravimetric datum orientation; interior orientation; preliminary orientation; relative orientation; single astronomic station datum orientation. HDBK-850
orientation inset See inset. HDBK-850
orientation point A picture point selected in areas common to vertical photographs and their corresponding obliques which serves to establish the relationship between the vertical and the oblique. Two such points are usually selected in each vertical photograph and transferred to the matching oblique photo. HDBK-850
origin The reference position from which angles, coordinates or distances are reckoned. See also false origin; grid origin. HDBK-850
original See original copy. HDBK-850
original copy The photographs, artwork, scribed material, typed matter, and/or other materials to be processed for reproduction. Also called original . HDBK-850
original model See master model. HDBK-850
original negative (ONEG) That negative developed from the film which was in a camera magazine at the instant of exposure. Synonymous with a first-generation photographic product. HDBK-850
original survey See survey. HDBK-850
orthochromatic (photography) 1. Of, pertaining to, or producing tonal values (of light or shade) in a photograph, corresponding to the tones of nature. 2. Designating an emulsion sensitive to blue and green light, but not to red. HDBK-850
orthodrome See great circle. HDBK-850
orthogonal At right angles; rectangularly; meeting, crossing, or lying at right angles. HDBK-850
orthogonal map projection See orthographic map projection. HDBK-850
orthographic chart A chart on the orthographic projection. HDBK-850
orthographic map projection A perspective azimuthal projection in which the projecting lines, emanating from a point at infinity, are perpendicular to a tangent plane. This projection is used chiefly in navigational astronomy for interconverting coordinates of the celestial equator and horizon systems. Also called orthogonal map projection. HDBK-850
orthometric correction A systematic correction which must be applied to measured difference observed through leveling. HDBK-850
orthometric elevation An elevation to which the orthometric correction has been applied. HDBK-850
orthometric height The distance of a point from the geoid measured along the direction of gravity at that point, with height of points outside the geoid being treated as positive. CEN/TC 287
orthomorphic chart A chart on which very small shapes are correctly represented. HDBK-850
orthomorphic map projection See conformal map projection. HDBK-850
orthophotograph A photographic copy, prepared from a perspective photograph, in which the displacements of images due to tilt and relief have been removed. HDBK-850
orthophotography The process of aerial photographs that have been rectified to produce an accurate image of the Earth by removing tilt and relief displacements that occurred when the photo was taken. USIS 95
orthophotomap A photomap made from an assembly of orthophotographs. It may incorporate special cartographic treatment, photographic edge enhancement, color separation, or a combination of these. HDBK-850
orthophotomosaic An assembly of orthophotographs forming a uniform scale mosaic. HDBK-850
orthophotoscope A photomechanical device, used for producing orthophotographs. HDBK-850
orthopictomap A pictomap made from an orthophotomap base. HDBK-850
orthorectification The process of removing image displacement caused by tilt and terrain relief. Tilt, however, is not relevant in radar images. HDBK-850
orthostereoscopy A condition wherein the horizontal and vertical distances in a stereoscopic model appear to be at the same scale. HDBK-850
oscillation A double motion, one in each direction, of a pendulum. An oscillation is composed of two successive vibrations. HDBK-850
osculating elements The elements that define an osculating orbit. See also osculating orbit. HDBK-850
osculating ellipse An ellipse that is tangent at a point (called the epoch of osculation) to a real orbit. HDBK-850
osculating orbit The ellipse that a satellite would follow after " "pecific time "t" (the epoch of osculation) if all forces other than central inverse square forces ceased t" "ct from time "t" on. An osculating orbit is tangent to the real perturbed orbit and has the same velocity at the point of tangency. HDBK-850
outer orientation See exterior orientation. HDBK-850
outer planet The planets with orbits larger than that of Mars; i.e., Jupiter, Saturn, Uranus, Neptune, and Pluto. HDBK-850
outlier A measurement which does not fit the remainder of measurements of the same quantity, where the reason for the discrepancy cannot be assessed. HDBK-850
outlier A gross error in data which lies outside of the normal distribution. ISO/TC 211
outline map (JCS) A map which represents just sufficient geographic information to permit the correlation of additional data placed upon it. HDBK-850
Outside Continental United States (OCONUS) Used to refer to the world outside the contiguous 48 states. USIS 95
overarching guidelines Dominant or all-embracing guidelines. [HCI Style Guide] DISA CFS
overcharging Applying excessive additional information (aeronautical or navigational) to a map or chart resulting in clutter. HDBK-850
overhang (aerial photography) The additional exposures beyond the boundary of an area to be photographed, usually two exposures at the ends of each strip to assure complete stereoscopic coverage. HDBK-850
overlap 1. (JCS) In photography, the amount by which one photograph includes the same area covered by another, customarily expressed as a percentage. The overlap between successive air photographs on a flight line is called forward overlap or forward lap. Also called end lap. The overlap between photographs in adjacent parallel light lines is called side overlap or side lap. 2. (JCS) In cartography, that portion of a map or chart which overlaps the area covered by another of the same series. 3. An area included within two surveys of record, which by record are described as having one or more common boundary lines with no inclusion of identical parts. HDBK-850
overlapping grid A major grid from a neighboring area primarily intended to facilitate military surveying and fire-control. See also major grid; secondary grid. HDBK-850
overlapping mean See consecutive mean. HDBK-850
overlapping pair (photogrammetry) Two photographs taken at different exposure stations in such a manner that a portion of one photograph shows the same terrain as shown on a portion of the other photograph. This term covers the general case and does not imply that the photographs were taken for stereoscopic examination. See also stereoscopic pair. HDBK-850
overlay 1. (JCS) A printing or drawing on a transparent or semitransparent medium at the same scale as a map, chart, etc., to show details not appearing, or requiring special emphasis, on the original. 2. (digital) A data layer, usually dealing with only one aspect of related information, which is used to supplement the data base, digital, image overlays, e.g., overlaying a raster base map with a vector shoreline map. Overlays are registered to the base by a common coordinate system. 3. (lithography) Additional data, or a pattern, printed after the other features, so as to "overlay" them. See also correction overlay; history overlay; radarscope overlays; selection overlay. HDBK-850
overprint 1. (JCS) Information printed or stamped upon a map or chart, in addition to that originally printed, to show data of importance or special use. Also called surprint. 2. A feature of a composite map image incidentally printed so as to interfere with another feature. HDBK-850
overrun control (JCS) Equipment enabling a camera to continue operating for a predetermined number of frames or seconds after normal cutoff. HDBK-850
oversheet A transparency or a print of a map compilation used for recording supplemental information. HDBK-850
oversize chart A chart whose neatlines have been extended slightly, thereby increasing the sheet size to include a small land area in order to avoid publishing a separate graphic of that area. HDBK-850

Last Updated by Mark Owens 7 January 1999.