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4 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
4.1 Actuator
A type of transducer that is a simple element that converts a signal to some action or real world phenomenon. In SensorML a actuator is a particular type of Process Model.
4.2 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.
4.3 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. 4.4
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 approximate the surface of the planetary body. 4.5
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. In SensorML a detector is a particular type of Process Model.
4.6 Determinand
A Parameter or a characteristic of a phenomenon subject to observation. Synonym for observable.
[OM]
4.7 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.
4.8 Location Model
A model that allows one to locate objects in one local reference frame relative to another reference frame.
4.9 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]
4.10 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.
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4.11 Measurement noun
An observation whose result is a measure
[OM]
4.12 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.
4.13 Observable, Observable Property noun
A parameter or a characteristic of a phenomenon subject to observation. Synonym for determinand.
[OM]
4.14 Observation noun
An act of observing a property or phenomenon, with the goal of producing an estimate of the value of the property. A specialized event whose result is a data value.
[OM]
4.15 Observed Value
A value describing a natural phenomenon, which may use one of a variety of scales including nominal, ordinal, ratio and interval. The term is used regardless of whether the value is due to an
instrumental observation, a subjective assignment or some other method of estimation or assignment.
[OM]
4.16 Orientation
The rotational relationship of an object relative to a coordinate system. Typically expressed by relating the rotation of an object’s local coordinate system relative to an external reference
coordinate system. 4.17
Phenomenon
A physical property that can be observed and measured, such as temperature, gravity, chemical concentration, orientation, number-of-individuals.
A characteristic of one or more feature types, the value for which must be estimated by application of some procedure in an observation.
4.18 Position
