SensorML OGC 12-000
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4 Terms and Definitions
For the purpose of this document, the following terms and definitions apply: 4.1. Actuator
A type of transducer that converts a signal to some real-world action or phenomenon.
4.2. Aggregate Process
Composite process consisting of interconnected sub-processes, which can in turn be Simple Processes or themselves Aggregate Processes. An aggregate process can include possible data
sources. A decription of an aggregate process should explicitly define connections that link input and output signals of sub-processes together. Since it is a process itself, an aggregate process also
has its own inputs, outputs and parameters.
4.3. Coordinate Reference System CRS
A spatial or temporal framework within which a position andor time can be defined. According to ISO 19111, a coordinate system that is related to the real world by a datum.
4.4. Coordinate System CS
According to ISO19111, a set of mathematical rules for specifying how coordinates are assigned to points. In this document, a Coordinate System is extended to be defined as a set of
axes with which location and orientation can be defined.
4.5. Data Component
Element of sensor data definition corresponding to an atomic or aggregate data type Note: A data component is a part of the overall dataset definition. The dataset structure can then
be seen as a hierarchical tree of data components.
4.6. Datum
Undefined in ISO 19111. Defined here as a means of relating a coordinate system to the real world by specifying the physical location of the coordinate system and the orientation of the axes
relative to the physical object. For a geodetic datum, the definition also includes a reference ellipsoid that approximates the physical or gravitational surface of the planetary body.
4.7. Detector
Atomic part of a composite Measurement System defining sampling and response characteristic of a simple detection device. A detector has only one input and one output, both being scalar
quantities. More complex Sensors, such as a frame camera, which are composed of multiple detectors, can be described as a detector group or array using a System or Sensor model.
4.8. Determinand
A Parameter or a characteristic of a phenomenon subject to observation. Synonym for observable.
[OM]
4.9. Feature
Abstraction of real-world phenomena [ISO 19101:2002, definition 4.11] Note: A feature may occur as a type or an instance. Feature type or feature instance should be
used when only one is meant.
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4.10. Location
A point or extent in space relative to a coordinate system. For point-based systems, this is typical expressed as a set of n-dimensional coordinates within the coordinate system. For bodies, this is
typically expressed by relating the translation of the origin of an object’s local coordinate system with respect to the origin of an external reference coordinate system.
4.11. Location Model
A model that allows one to locate objects in one local reference frame relative to another reference frame.
4.12. Measurand
Physical parameter or a characteristic of a phenomenon subject to a measurement, whose value is described using a Measure ISO 19103. Subset of determinand or observable.
[OM]
4.13. Measure noun
Value described using a numeric amount with a scale or using a scalar reference system
[ISOTS 19103]
. When used as a noun, measure is a synonym for physical quantity
4.14. Measurement noun
An observation whose result is a measure
[OM]
4.15. Measurement verb
An instance of a procedure to estimate the value of a natural phenomenon, typically involving an instrument or sensor. This is implemented as a dynamic feature type, which has a property
containing the result of the measurement. The measurement feature also has a location, time, and reference to the method used to determine the value. A measurement feature effectively binds a
value to a location and to a method or instrument.
4.16. Muliplexed Data Stream
A data stream that consists of disparate but well defined data packets within the same stream.
4.17. Observable, Observable Property noun
