SEDRIS GLOSSARY
SEDRIS encompasses the environmental domain, which is described using its own unique definition of terms. To ensure a common understanding of terminology, definitions of these domain specific words and phrases are provided below.
Terminology definitions are preliminary; they are being verified to ensure that they represent the intended SEDRIS usage.
NOTE: The terms and definitions below makeup the SEDRIS Glossary as of 16 November 2000. The current version of the SEDRIS Glossary at http://www.sedris.org/glossary.htm
2-D+ topology - the addition of a z component to the traditional two dimensional (x and y) topology.
3-D model - three-dimensional, refers to the visual display that exhibits breadth, height, and thickness or depth.
Aggregation - a relationship between objects in the data representation model where one object contains other objects.
Aggregator - an object that is comprised of other objects (components). A'has-a' relationship exists between the aggregator object and its component (see component) objects. For example, a polygon is an aggregator for its vertex objects (components). Synonym: container.
Application programmer's interface (API) - an encapsulation of functionalities common to many applications into reusable modules. This encapsulation provides consistency among applications, as well as a reduction in complexity for access of data.
Areal feature - a geographic entity that encloses a region. For example, a lake, administrative area, or state.
Association - a relationship between two or more objects in a data representation model. This is the weakest relationship, and can include multiplicity of objects at either end of the relationship.
Atmospheric representation - the depiction of the atmosphere environment which includes data on the location and characteristics of the zone from the earth's surface to the upper boundary of the troposphere, and includes: (a) particulate and aerosol data on haze, dust, and smoke (to include nuclear, biological, and chemical effects), and (b) data on fog, clouds, precipitation, wind, condensation (humidity), obscurants, contaminants, radiated energy, temperature, and illumination.
Attribute - a quantifiable property of an object. For example, the color of a building or the width of a road.
Base - 1: the 'world' encompassed by an environment. Boundaries are specified to define the extent of the Base. 2: the root of an environment object hierarchy of objects with fixed positions in the world.
Business Rules - usage rules for development of SEDRIS transmittals based upon the SEDRIS data representation model.
Component - an object that is a part of an aggregator object. For example, vertex objects are components of their aggregator polygon. See aggregator.
Computer generated forces (CGF) - a generic term used to refer to computer representations of forces in simulations that attempt to model human behavior sufficiently, so that the forces will take some actions automatically (without requiring man-in-the-loop interaction). Also referred to as semi-automated forces (SAF).
Constructive simulation - models and simulations that involve simulated people operating simulated systems. Real people stimulate (make inputs to) such simulations, but are not involved in determining the outcomes.
Consumer - see resource consumers.
Container - see aggregator.
Coordinate system - an organized system for describing 2- or 3-dimensional locations.
Correlated initial environment - the convergent representation of the same physical environment in two or more separate environments prior to their use in a combined exercise.
Correlated levels of detail (LOD) - the equal representation of environmental objects at comparable levels of presentation (i.e., the same object seen or detected at a distance of 15 meters).
Correlation - a convergent relationship between parallel representations of the same data.
Data derivation - the calculation or interpolation of information not present in the original data.
Data dictionary - a table or set of records whose values define the allowable content and meaning of attributes.
Data loss - the loss of original information through multiple conversions or transformations of data.
Data representation model - 1: a description of the organization of data in a manner that reflects the information structure of an enterprise. 2: a description of the logical relationships between data elements. Each major data element with important or explicit relationships is captured to show its logical relationship to other data elements.
Data pre-distribution interchange - the complete exchange of environmental data prior to the start of an exercise.
Data representation - a variety of forms used to describe the terrain surface itself, the features placed on the terrain, the dynamic objects with special 3-D model attributes and characteristics, the atmospheric and oceanographic features, and many other forms of data.
Edge - a one dimensional primitive used to represent the location of a linear feature and/or the border of faces.
Elevation - the vertical component in a 3-dimensional measurement system. Elevation is measured in reference to a fixed datum.
Environment - [distributed] simulations that represent activities at a high level of realism, from simulations of theaters of war, to factories and manufacturing processes. These environments may be created within a single computer, or a vast distributed network connected by local and wide area networks and augmented by super-realistic special effects and accurate behavioral models. They allow visualization of and immersion into the environment being simulated.
Environmental database - an integrated set of data elements, each describing some aspect of the same geographical region and the elements or events expected there.
Environmental domain - the physical or abstract space in which the entities and processes operate. The domain can be land, sea, air, space, undersea, a combination of any of the above (including permanent or semi-permanent man-made features), or an abstract domain, such as an n-dimensional mathematics space, or economic or psychological domains.
Environmental phenomena - an individual element of the physical environment (e.g., a rain system, fog, cloud).
Environmental representation - an authoritative representation of all or part of the natural environment, including permanent or semi-permenent man-made features.
Face - a region enclosed by an edge or set of edges. 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 a plane.
Fair fight - a simulation or exercise conducted such that differences in the simulator or trianing system technology do not unduly result in one force or entity having an advantage over another.
Feature - 1: a model of a real world entity. 2: a static element of the environment which exists but does not actively participate in environmental interactions.
Fidelity - 1: the accuracy of the representation when compared to the real world. 2: (a) the similarity, both physical and functional, between the simulation and that which it simulates, (b) ameasure of the realism of a simulation, or (c) the degree to which the representation within a simulation is similar to a real world object, feature, or condition in a measurable or perceivable manner.
GCS cell - each cell covers one degree of latitude by one degree of longitude.
GeoDetic Coordinate system (GDC) - a measurement system that relates earth-centered angular latitude and longitude (and optionally height) to an actual point near or on the earth's surface.
Geometry - a very abstract class, encapsulating both the concepts of traditional geometry as well as other classes containing measured data, and organizational methods used to organize these traditional geometry and other 'real' data classes within an environment.
Ground truth - the actual facts of a situation, without errors introduced by sensors or human perception and judgment. For example, the actual location, orientation, and engine and gun state of an M1A1 tank in a live simulation at a certain point in time is the ground truth that could be used to check the same quantities in a corresponding virtual simulation. Or the actual direct and diffuse solar irradiance at a terrain point is the ground truth that could be used to check the same quantity in a corresponding virtual simulation.
Inheritance - the object-oriented concept where a child class also has the features (attributes and methods) of its parent class. One of the types of relationships between objects in the data representation model.
Interchange -
Interoperability - 1: enables distributed heterogeneous simulation systems to be interactive so that a meaningful exercise may be conducted. 2: the ability of a model or simulation to provide services to and accept services from other models and simulations, and to use the services so exchanged to enable them to operate effectively together. 3: two training systems interoperating to present a single training exercise in the same simulated space to a geographically dispersed audience.
Intervisibility - the translucency of superimposed visual objects (e.g., the ability to see through the leaves of a tree).
Ionosphere representation - see space representation.
Levels of topology - level 0 topology manipulates the purely geometric aspects of the spatial data. No topological information is stored in level 0 topology. Level 1 topology maintains a non-planar graph. Level 2 topology maintains a planar graph. Level 3 topology explicitly represents the faces defined by the planar graph.
Library - a complete list of unique item(s) of a certain type (whatever type the library contains) which can be referenced within the environment.
Linear network - a geographic entity that defines a linear (one-dimensional) structure. For example, a river, a road, or a state boundary.
Link association - a class containing the attributes of an association (link) between two other classes. The link association is depicted using the 'horse-collar' symbol. The attributes in a link association class are properties of the association, not the classes linked by the association.
Littoral region - 1: defined as (a) seaward - the area from the open oceans to the shore that must be controlled to support operations ashore, and (b)
landward - the area inland from the shore that can be supported and defended directly from the sea. 2: the area from the ten-fathom curve shoreward to the most inland point of the shoreline.
Live simulation - a simulation involving real people operating real systems.
Location 3-D vertex - a coordinate in 3-dimensional space.
Loss-less -
Man-In-the-Loop (MIL) - a model that requires human participation.
Metadata - information describing the characteristics of data. Data or information about data. Descriptive information about an organization's data, data activities, systems, and holdings.
Model - a physical, mathematical, or otherwise logical representation of a system, entity, phenomenon, or process.
Natural environment - the earth-based environment modeled by an environment.
Node - a zero-dimensional primitive used to store a significant location.
Oceanographic representation - the depiction of the ocean environment which includes data on the location and characteristics of the ocean bottom (e.g., depth curves, bottom contours, sediment types), as well as the representation of processes required to describe the natural and man-made static and dynamic surface and sub-surface ocean conditions (e.g., temperature, salinity gradients, acoustic phenomena).
Original data - the source data utilized by a resource provider to construct their initial environmental representation.
Out-the-window - human eye view of a visible spectrum environment through the viewport or window of a physical model of a tactical vehicle.
Point feature - a geographic entity that defines a zero-dimensional location. For example, a well or a building.
Polygon - thematically homogenous areas composed of one or more faces.
Positional accuracy - positional accuracy refers to the root mean square error (RMSE) of the coordinates relative to the position of the real world entity being modeled. Positional accuracy shall be specified without relation to scale and shall contain all errors introduced by source documents, data capture, and data processing.
Provider - see resource providers.
Projected coordinate system (PCS) - an instantiation of a coordinate transformation. A planar, right-handed cartesian coordinate set which, for a specific map projection, has a single and unambiguous transformation to a geodetic coordinate system.
Property - a characteristic of an object.
Read API - a collection of routines which provide the capability to extract data from a SEDRIS transmittal.
Representational polymorphism - multiple representations of the same data to serve the needs of different users.
Resolution - the degree of detail and precision used in the representation of real-world aspects in a model or simulation. Granularity.
Resource consumers - organizations that want to convert a SEDRIS transmittal generated by a provider into their database native format.
Resource providers - organizations that provide either complete environmental databases or the raw data that is used by database generation systems to produce environmental databases.
Scalability - the ability of a distributed simulation to maintain time and spatial consistency, as the number of entities and accompanying interactions increase.
SEDRIS application - any application software that can consume a SEDRIS transmittal (e.g., to view, verify, or validate the data; or to convert to a target format).
SEDRIS transmittal - 1: the combination of a data provider's implementation of the Read API and that provider's native database. 2: a particular data set that is represented in compliance with the SEDRIS data representation model for the purpose of interchange in memory or through the SEDRIS transmittal format.
Semantics - the implied meaning of data. Used to define what entities mean with respect to their roles in a system.
SEDRIS transmittal format (STF) - provides users of SEDRIS, both data consumers and data providers, with a means of cross-platform interchange by supplying a universally specified external storage format.
Semantics - the implied meaning of data. Used to define what entities mean with respect to their roles in a system.
Semi-automated forces (SAF) - see computer generated forces.
Sensor model - a model of a sensing system (sensor) other than a direct human eye visual model. It may and usually does include a sensor signature model, a sensor atmospheric model, and a sensor effects model. It may also include human perception response for CGF simulation. Examples of sensor models include radar system models, sonar system models, FLIR (forward looking infrared) imager models, and NVG (night vision goggle) models.
Source format - the data file format in which the environment is stored prior to interchange.
Space representation (including ionosphere) - the depiction of the space environment which includes data on the location and characteristics of regions beyond the upper boundary of the troposphere, and including neutral and charged atomic and molecular particles and their optical properties.
Terrain representation - the depiction of the terrain environment, which includes data on the location and characteristics of the configuration and composition of the surface of the earth, including its relief, natural features, permanent or semi-permanent man-made features, and related processes. It includes seasonal and diurnal variation, such as grasses and snow, foliage coverage, tree type, and shadow. The terrain surface includes inland waters, and the sea floor bottom to the 10 meter depth curve.
Terrain skin - the geometrical portion of the terrain representation that model's the earth's surface, including terrain polygons, vertices, and vertex normals.
Textures - application of surface detail to a polygon by mapping an image to the polygon (i.e., to show foliage on a polygon to represent a tree).
Tile - a spatial partition of a coverage that shares the same set of feature classes with the same definitions as the coverage.
Token set - a special type of attribute within a SEDRIS class. It's an attribute that can contain multiple values.
Topology - refers to any relationship between connected geometric primitives that is not altered by continuous transformation.
Transfer format - specification of the actual byte level descriptions of the physical files of a SEDRIS transmittal.
Transmittal format - a platform-independent interchange format for SEDRIS transmittals.
Traversal - an ordered inspection of an object hierarchy within a SEDRIS transmittal.
Universal Transverse Mercator (UTM) PCS - an ellipsoidal transverse mercator projection to which specific parameters, such as central meridians, have been applied. The earth, between latitudes 84.0 degrees North and 80.0 degrees South, is divided into 60 zones, each generally 6 degrees wide in longitude.
Virtual simulation - a simulation involving real people operating simulated systems. Virtual simulations inject [man]-in-the-loop in a central role by exercising motor control skills (e.g., flying an airplane), decision skills (e.g., acquiring a target through a sensor and committing fire control resources to action), or communication skills (e.g., as members of a C4I team).
World Geodetic System (WGS-84) - defines the current U.S. DoD standard horizontal and vertical reference datums for a geodetic coordinate system, collected and standardized in 1984.
Write API - a collection of routines which provide the capability to store a SEDRIS transmittal to an external storage media.