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traceability property of the result of a measurement or the value of a standard whereby it can be related to stated references,
usually national or international standards, through an unbroken chain of comparisons all having stated uncertainties [International Vocabulary of Basic and General Terms in Metrology VIM]
uncertainty of measurement parameter, associated with the result of a measurement, that characterizes the dispersion of the values that could
reasonably be attributed to the measurand
NOTE 1 The parameter may be, for example, a standard deviation or a given multiple of it, or the half-width of an interval
having a stated level of confidence. NOTE 2
Uncertainty of measurement comprises, in general, many components. Some of these components may be evaluated from the statistical distribution of the results of series of measurements and can be characterized by experimental standard
deviations. The other components, which can also be characterized by standard deviations, are evaluated from assumed probability distributions based on experience or other information.
NOTE 3 It is understood that the result of the measurement is the best estimate of the value of the measurand, and that all
components of uncertainty, including those arising from systematic effects, such as components associated with corrections and reference standards, contribute to the dispersion.
viewpoint on a system form of abstraction achieved using a selected set of architectural concepts and structuring rules, in order to focus on
particular concerns within a system. [ISOIEC 10746-2]
5 Symbols and abbreviated terms
5.1 Abbreviations
The following abbreviations are used in this Technical Specification. DCP Distributed
Computing Platform
IT Information Technology
ODP Open Distributed Processing see RM-ODP
OGC Open GIS Consortium
RM-ODP Reference Model of Open Distributed Processing ISOIEC 10746
TBS To Be Supplied
UML Unified Modelling Language
VIM International Vocabulary of Basic and General Terms in Metrology
XML Extensible Markup
Language
5.2 Symbols
TBS
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7 5.3 Notation
The conceptual schema specified in this Technical Specification is described using the Unified Modelling Language UML [3], following the guidance of ISOTS 19103. Several model elements used in this schema are defined in other
ISO standards developed by ISOTC 211. Names of UML classes, with the exception of basic data type classes, include a two-letter prefix that identifies the standard and the UML package in which the class is defined. Table 2 lists
the other standards and packages in which UML classes used in this International Standard have been defined.
Table 1 — Sources of externally defined UML classes Prefix Standard Package
CV ISO 19123
Coverages FC
ISO 19110 Feature catalgouing
IG ISO 19101-2
Reference model - Imagery MD ISO
19115 Metadata
PS ISO 19116
Positioning services
6 Geographic Imagery Systems
6.1 Geographic imagery as features
In the ISO 19100 series of standards a geographic image is a type of coverage, and a coverage is a type of feature. A feature is an abstraction of real world phenomena See ISO 19101. A geographic feature has implicit or explicit
reference to a location relative to the Earth. A coverage is a feature that acts as a function to return values from its range for any direct position within its
spatiotemporal domain See ISO 19123. Examples of coverages include an image, a polygon overlay, or a digital elevation matrix.
A grid may be used to structure the domain of a coverage. As defined in ISO 19123, a grid is a network composed of two or more sets of curves in which the members of each set intersect the members of the other sets in an algorithmic
way.
A geographic image shall be a gridded coverage whose range values quantitatively describe physical phenomena. Physical quantities, as defined in IS0 31-0 Quantities and units - Part 0: General principles, shall be used in a
geographic image for the quantitative description of physical phenomena. Conventional scales, such as the Beaufort scale, Richter scale, colour intensity scales, and land cover classification, shall not be used as range values for a
geographic image. Conventional scales may be used in other types of geographic coverages. The physical quantities of a geographic image may be the result of measurement by a sensor or from a prediction by a physical model.
The definition for geographic image is tightly constrained in this Technical Specification following the semiotic concept of icon. Geographic imagery as iconic signs have a relationship that shall be very precise, such that relationships
among elements in a geographic image are isomorphic to relationships among elements in the object. A photograph of a geographic scene conforms to this definition.
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Requiring the data of an image to be organized in a grid reflects that an image is a uniform method for representing the physical phenomena. A random set of point data from a sensor is not an image.
It is useful to distinguish between image as used in this Technical Specification, and the colloquial use of the term ‘image’. As used in this Technical Specification, an image is a representation of image data within a computer system.
To view an image, a presentation process is required. The definition used in this Technical Specification is consistent with ‘image’ or ‘digital image’ as defined in ISOIEC 12087-1: Common architecture for imaging.
To place geographic imagery in the larger context of digital imagery, various types of image encodings are shown in the image state diagram of Figure 1. Figure 1 is nearly identical to the image state diagram of ISO 22028-1:2004,
Photography and graphic technology — Extended colour encodings for digital image storage, manipulation and interchange — Part 1: Architecture and requirements. ISO 22028-1 categorizes image encodings into scene-referred or
picture-referred image states.
Figure 1 - Image state diagram with modifications for geographic imagery
Scene-referred encodings are representations of an original scene, where a scene is defined to be the spectral radiances of a view of the natural world as measured from a specified vantage point in space and at a specified time.
Scene-referred image data may correspond to an actual view of the natural world, or to a computer-generated virtual scene simulating such a view. To accommodate geographic imagery, this Technical Specification has modified the
image state diagram of ISO 22028-1 by changing from “Scene-referred coulour encoding” to “Scene-referred image encoding.” Geographic imagery makes use of a much broader spectrum than the colours addressed by ISO 22028-1.
This Technical Specification applies the approach of feature modeling of the 19100-series of international standards to the Scene-referred image encodings. This Technical Specification emphasizes images derived from scene-referred
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image encodings, such as derivation of geophysical values based on sensor measurements. These derived images are also considered to be scene-referred image encodings.
Picture-referred colour encodings are representations of the colour-space coordinates of a hardcopy or softcopy image. Picture-referred colour encodings can be further subdivided into original-referred colour encodings and output-referred
colour encodings.
Original-referred colour encodings are representative of the colour-space coordinates or an approximation thereof of a two-dimensional hardcopy or softcopy input image. For geographic information, original-referred colour encodings
could be obtained from printed maps, printed pictures of a geographic scene, drawings of geographic information, etc. Although an original-referred colour encoding may be of a picture of a geographic scene, because the picture was
previously colour-rendered for printing, it is not a scene-referred image encoding.
Output-referred colour encodings are representative of the colour-space coordinates of image data that are appropriate for a specified real or virtual output device and viewing conditions. Output-referred colour encodings are tightly coupled
to the characteristics of a particular real or virtual output device and viewing conditions. Portrayal of geographic information is addressed in ISO 19117, Geographic Information – Portrayal.
Picture-referred colour encodings are colour encodings of any type of geographic information including, but not limited, to geographic imagery. Issues such as false-colour rendering must be addressed to transform the broader spectrum of
geographic imagery into colour imagery. Picture-referred colour encodings are addressed in this Technical Specification in Clause 8.5.3, Visualization.
6.2 Open distributed processing of geographic imagery
