Astronomical Measurements Model

Table of Contents

1.     model: meas
2.     Packages and Types
2.1     [root package]
2.1.1     dataType:Asymmetrical1D
2.1.2     dataType:Asymmetrical2D
2.1.3     dataType:Asymmetrical3D
2.1.4     dataType:Bounds1D
2.1.5     dataType:Bounds2D
2.1.6     dataType:Bounds3D
2.1.7     objectType:CartesianPosition
2.1.8     dataType:CovarianceMatrix
2.1.9     objectType:EclipticPosition
2.1.10     dataType:Ellipse
2.1.11     dataType:Ellipsoid
2.1.12     objectType:EquatorialPosition
2.1.13     objectType:Error
2.1.14     objectType:GalacticPosition
2.1.15     objectType:GenericMeasure
2.1.16     objectType:GenericPosition
2.1.17     objectType:GenericVelocity
2.1.18     dataType:Matrix
2.1.19     dataType:Matrix2x2
2.1.20     dataType:Matrix3x3
2.1.21     objectType:Measure
2.1.22     objectType:Polarization
2.1.23     objectType:Position
2.1.24     objectType:Position1D
2.1.25     objectType:Position2D
2.1.26     objectType:Position3D
2.1.27     objectType:ProperMotion
2.1.28     dataType:Symmetrical
2.1.29     objectType:Time
2.1.30     dataType:Uncertainty
2.1.31     objectType:Velocity
2.1.32     objectType:Velocity1D
2.1.33     objectType:Velocity2D
2.1.34     objectType:Velocity3D
3.     vodml-id-s
4.     Imported Models
4.1     coords
4.2     ivoa

1. Model: Astronomical Measurements Model (meas)

Authors : Arnold Rots, Mark Cresitello-Dittmar, Omar Laurino
Date : 2019-08-30T16:28:12
Version : 2.0
Previous version: : 0.x
Abstract : This model defines objects and datatypes which represent 'measured' or 'determined' data. It associates a Coordinate (ie: the determined value) with corresponding Error(s). As such, this model is at least the foundation for representing the vast majority of the Astronomical data found in catalogs and data products. We define here, several specialized classes which cover the most basic and common types, such as Position and Time. We also provide a generic model which can accommodate virtually any data, but may require a bit more effort to fully describe the coordinate metadata. Additional specializations, e.g. Flux, Magnitude, Luminosity, Pressure, Temperature, etc. may be added to this model, or in other models focusing on particular domains or use cases. We include a fairly simple Error model, describing errors as a 'shape' of uncertainty, and define a small set of commonly occuring forms (e.g. Symmetrical, Bounds, Ellipsoid).
Diagram : The following diagram has been generated from the model using the GraphViz tool.
The classes and packages in the diagram can be clicked and are mapped to the descriptions of the corresponding element elsewhere in the document.

2.Model contents: Packages and Types

The following sub-sections present all packages in the model with their types. The packages are listed here in alphabetical order. Each sub-section contains a description of the package and a table containing its various features.

2.1 [root package]

Model meas
Object types CartesianPosition EclipticPosition EquatorialPosition Error GalacticPosition GenericMeasure GenericPosition GenericVelocity Measure Polarization Position Position1D Position2D Position3D ProperMotion Time Velocity Velocity1D Velocity2D Velocity3D
Data types Asymmetrical1D Asymmetrical2D Asymmetrical3D Bounds1D Bounds2D Bounds3D CovarianceMatrix Ellipse Ellipsoid Matrix Matrix2x2 Matrix3x3 Symmetrical Uncertainty

2.1.1 dataType: Asymmetrical1D

vodml-id Asymmetrical1D
description Uncertainty with different extent in the positive and negative directions from the associated Coordinate.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
plus type ivoa:RealQuantity
vodml-id Asymmetrical1D.plus
multiplicity 1
description Extent in the positive axis direction.
minus type ivoa:RealQuantity
vodml-id Asymmetrical1D.minus
multiplicity 1
description Extent in the negative axis direction.

2.1.2 dataType: Asymmetrical2D

vodml-id Asymmetrical2D
description 2D Uncertainty with different extent in the positive and negative axis directions from the associated Coordinate. i.e.: an offset rectangle.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
plus type ivoa:RealQuantity
vodml-id Asymmetrical2D.plus
multiplicity 2
description Extent in each positive axis direction.
minus type ivoa:RealQuantity
vodml-id Asymmetrical2D.minus
multiplicity 2
description Extent in each negative axis direction.

2.1.3 dataType: Asymmetrical3D

vodml-id Asymmetrical3D
description 3D Uncertainty with different extent in the positive and negative axis directions from the associated Coordinate. i.e.: an offset box.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
plus type ivoa:RealQuantity
vodml-id Asymmetrical3D.plus
multiplicity 3
description Extent in each positive axis direction.
minus type ivoa:RealQuantity
vodml-id Asymmetrical3D.minus
multiplicity 3
description Extent in each negative axis direction.

2.1.4 dataType: Bounds1D

vodml-id Bounds1D
description Provide the edges of the uncertainty space. Rather than being relative to the associated Coordinate, these represent a range within that Coordinate space.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
loLimit type ivoa:RealQuantity
vodml-id Bounds1D.loLimit
multiplicity 1
description Lower limit of the uncertainty range.
hiLimit type ivoa:RealQuantity
vodml-id Bounds1D.hiLimit
multiplicity 1
description Upper limit of the uncertainty range.

2.1.5 dataType: Bounds2D

vodml-id Bounds2D
description Provide the edges of a 2D uncertainty space. Rather than being relative to the associated Coordinate, these represent ranges along each axis of that Coordinate space.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
loLimit type ivoa:RealQuantity
vodml-id Bounds2D.loLimit
multiplicity 2
description Lower edges of the uncertainty rectangle.
hiLimit type ivoa:RealQuantity
vodml-id Bounds2D.hiLimit
multiplicity 2
description Upper edges of the uncertainty rectangle.

2.1.6 dataType: Bounds3D

vodml-id Bounds3D
description Provide the edges of a 3D uncertainty space. Rather than being relative to the associated Coordinate, these represent ranges along each axis of that Coordinate space.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
loLimit type ivoa:RealQuantity
vodml-id Bounds3D.loLimit
multiplicity 3
description Lower edges of the uncertainty box.
hiLimit type ivoa:RealQuantity
vodml-id Bounds3D.hiLimit
multiplicity 3
description Upper edges of the uncertainty box.

2.1.7 objectType: CartesianPosition

vodml-id CartesianPosition
description 3-Dimensional position in an cartesian coordinate space.
extends Position [meas:Position]
attributes
name feature value
x type coords:X
vodml-id CartesianPosition.x
multiplicity 1
description X-Axis value.
y type coords:Y
vodml-id CartesianPosition.y
multiplicity 1
description Y-Axis value.
z type coords:Z
vodml-id CartesianPosition.z
multiplicity 1
description Z-Axis value.

2.1.8 dataType: CovarianceMatrix

vodml-id CovarianceMatrix
description Uncertainty expressed as a covariance matrix.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
matrix type Matrix [meas:Matrix]
vodml-id CovarianceMatrix.matrix
multiplicity 1
description The m x m matrix, where m is the number of dimensions of the associated Coordinate.

2.1.9 objectType: EclipticPosition

vodml-id EclipticPosition
description 2-Dimensional position in an ecliptic coordinate space. All contained coordinates MUST be associated with the same SpaceFrame instance.
extends Position [meas:Position]
attributes
name feature value
elon type coords:Longitude
vodml-id EclipticPosition.elon
multiplicity 1
description Ecliptic Longitude. The corresponding SpaceFrame MUST specify an ecliptic reference frame, with appropriate reference position.
elat type coords:Latitude
vodml-id EclipticPosition.elat
multiplicity 1
description Ecliptic Latitude. The corresponding SpaceFrame MUST specify an ecliptic reference frame, with appropriate reference position.

2.1.10 dataType: Ellipse

vodml-id Ellipse
description Elliptical uncertainty shape.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
semiAxis type ivoa:RealQuantity
vodml-id Ellipse.semiAxis
multiplicity 2
description Extent of the semi-major and semi-minor axes, provided in the order of the associated Coordinate axes.
posAngle type ivoa:RealQuantity
vodml-id Ellipse.posAngle
multiplicity 1
description Position angle, counter-clockwise from the positive direction of the first axis of the associated Coordinate.

2.1.11 dataType: Ellipsoid

vodml-id Ellipsoid
description Ellipsoidal uncertainty shape.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
semiAxis type ivoa:RealQuantity
vodml-id Ellipsoid.semiAxis
multiplicity 3
description Extent of the semi axes, provided in the order of the associated Coordinate axes.
posAngle type ivoa:RealQuantity
vodml-id Ellipsoid.posAngle
multiplicity 2
description Position angles, counter-clockwise from the positive direction of the first axis toward the second axis, and angle 'above' the plane of the first two axes of the associated Coordinate.

2.1.12 objectType: EquatorialPosition

vodml-id EquatorialPosition
description 2-Dimensional position in an equatorial coordinate space. All contained coordinates MUST be associated with the same SpaceFrame instance.
extends Position [meas:Position]
attributes
name feature value
ra type coords:Longitude
vodml-id EquatorialPosition.ra
multiplicity 1
description Right Ascension. The corresponding SpaceFrame MUST specify an equatorial reference frame, with appropriate reference position and equinox.
dec type coords:Latitude
vodml-id EquatorialPosition.dec
multiplicity 1
description Declination. The corresponding SpaceFrame MUST specify an equatorial reference frame, with appropriate reference position and equinox.

2.1.13 objectType: Error

vodml-id Error
description The Error class uses the Uncertainty types to describe measurement errors from various sources.
attributes
name feature value
statError type Uncertainty [meas:Uncertainty]
vodml-id Error.statError
multiplicity 0..1
description Statistical error. The Uncertainty type MUST be dimensionally compatible with the associated Measure value.
sysError type Uncertainty [meas:Uncertainty]
vodml-id Error.sysError
multiplicity 0..1
description Systematic error. The Uncertainty type MUST be dimensionally compatible with the associated Measure value.
ranError type Uncertainty [meas:Uncertainty]
vodml-id Error.ranError
multiplicity 0..1
description Random error. The Uncertainty type MUST be dimensionally compatible with the associated Measure value.

2.1.14 objectType: GalacticPosition

vodml-id GalacticPosition
description 2-Dimensional position in an galactic coordinate space. All contained coordinates MUST be associated with the same SpaceFrame instance.
extends Position [meas:Position]
attributes
name feature value
l type coords:Longitude
vodml-id GalacticPosition.l
multiplicity 1
description Galactic Longitude. The corresponding SpaceFrame MUST specify an galactic reference frame, with appropriate reference position.
b type coords:Latitude
vodml-id GalacticPosition.b
multiplicity 1
description Galactic Latitude. The corresponding SpaceFrame MUST specify an galactic reference frame, with appropriate reference position.

2.1.15 objectType: GenericMeasure

vodml-id GenericMeasure
description The most generic Measure class. This class may be used to represent any data not covered by the specialized cases. The coordinate value type allows for the construction of multi-dimensional values to accommodate virtually any case.
extends Measure [meas:Measure]
attributes
name feature value
coord type coords:Coordinate
vodml-id GenericMeasure.coord
multiplicity 1
description The measured coordinate value. May be of any dimensionality (current support 1,2 and 3-dimension). For many cases, the Standard1DCoord should suffice, providing a clean and simple representation of the measured value. For other cases, users will need to provide a complete coordinate description.

2.1.16 objectType: GenericPosition

vodml-id GenericPosition
description Generic positional instant, appropriate for describing positional data not covered by the specialized classes. Any concrete extension of this class MUST define a specific dimensionality for the coord attribute. We provide 1,2 and 3-dimensional classes to cover the most common cases.
extends Position [meas:Position]
abstract True
Subclasses in this model Position1D Position2D Position3D
attributes
name feature value
coord type coords:CoordValue
vodml-id GenericPosition.coord
multiplicity 0..*
description The measured position value. May be given by any CoordValue type associated with a SpaceFrame.

2.1.17 objectType: GenericVelocity

vodml-id GenericVelocity
description Generic velocity instant, appropriate for describing velocity data not covered by the specialized classes. Any concrete extension of this class MUST define a specific dimensionality for the coord attribute. We provide 1,2 and 3-dimensional classes to cover the most common cases.
extends Velocity [meas:Velocity]
abstract True
Subclasses in this model Velocity1D Velocity2D Velocity3D
attributes
name feature value
coord type coords:CoordValue
vodml-id GenericVelocity.coord
multiplicity 0..*
description The measured velocity value. May be given by any CoordValue type associated with a SpaceFrame.

2.1.18 dataType: Matrix

vodml-id Matrix
description Abstract Matrix data type.
abstract True
Subclasses in this model Matrix2x2 Matrix3x3

2.1.19 dataType: Matrix2x2

vodml-id Matrix2x2
description 2x2 matrix data type.
extends Matrix [meas:Matrix]
attributes
name feature value
m11 type ivoa:real
vodml-id Matrix2x2.m11
multiplicity 1
description matrix cell; i=1, j=1
m12 type ivoa:real
vodml-id Matrix2x2.m12
multiplicity 1
description matrix cell; i=1, j=2
m21 type ivoa:real
vodml-id Matrix2x2.m21
multiplicity 1
description matrix cell; i=2, j=1
m22 type ivoa:real
vodml-id Matrix2x2.m22
multiplicity 1
description matrix cell; i=2, j=2

2.1.20 dataType: Matrix3x3

vodml-id Matrix3x3
description 3x3 matrix data type.
extends Matrix [meas:Matrix]
attributes
name feature value
m11 type ivoa:real
vodml-id Matrix3x3.m11
multiplicity 1
description matrix cell; i=1, j=1
m12 type ivoa:real
vodml-id Matrix3x3.m12
multiplicity 1
description matrix cell; i=1, j=2
m13 type ivoa:real
vodml-id Matrix3x3.m13
multiplicity 1
description matrix cell; i=1, j=3
m21 type ivoa:real
vodml-id Matrix3x3.m21
multiplicity 1
description matrix cell; i=2, j=1
m22 type ivoa:real
vodml-id Matrix3x3.m22
multiplicity 1
description matrix cell; i=2, j=2
m23 type ivoa:real
vodml-id Matrix3x3.m23
multiplicity 1
description matrix cell; i=2, j=3
m31 type ivoa:real
vodml-id Matrix3x3.m31
multiplicity 1
description matrix cell; i=3, j=1
m32 type ivoa:real
vodml-id Matrix3x3.m32
multiplicity 1
description matrix cell; i=3, j=2
m33 type ivoa:real
vodml-id Matrix3x3.m33
multiplicity 1
description matrix cell; i=3, j=3

2.1.21 objectType: Measure

vodml-id Measure
description Abstract base of Measure classes, associates a 'determined value' (Coordinate) with corresponding errors. We associate the Error(s) with the full Measure, rather than the individual values, in order to support both correlated and uncorrelated errors. In many cases with multi-dimensional data, the associated errors are correlated and must be considered with the value set as a whole. One consequence of this approach is that there is a looser association between the Error dimensions and the corresponding value dimension. We require that the Error content MUST be compatible with the value dimension and nature (e.g. dimension, domain, units, etc).
abstract True
Subclasses in this model GenericMeasure Polarization Position Time Velocity
compositions
name feature value
error type Error [meas:Error]
vodml-id Measure.error
multiplicity 0..*
isOrdered false
description Measurement error.

2.1.22 objectType: Polarization

vodml-id Polarization
description Provides a complete description of a determined polarization state. Since the polarization coordinate is an enumerated type, there can be no associated numerical error sources.
extends Measure [meas:Measure]
attributes
name feature value
coord type coords:PolCoordValue
vodml-id Polarization.coord
multiplicity 1
description Determined polarization state. May be provided by any of the PolCoordValue subtypes.
constraints
error:Error[0]

2.1.23 objectType: Position

vodml-id Position
description Provides a complete description of a measured positional instant.
extends Measure [meas:Measure]
abstract True
Subclasses in this model CartesianPosition EclipticPosition EquatorialPosition GalacticPosition GenericPosition
constraints
coordinate frames = same SpaceFrame

2.1.24 objectType: Position1D

vodml-id Position1D
description Generic 1-Dimensional position.
extends GenericPosition [meas:GenericPosition]
constraints
coord:CoordValue[1]

2.1.25 objectType: Position2D

vodml-id Position2D
description Generic 2-Dimensional position.
extends GenericPosition [meas:GenericPosition]
constraints
coord:CoordValue[2]

2.1.26 objectType: Position3D

vodml-id Position3D
description Generic 3-Dimensional position.
extends GenericPosition [meas:GenericPosition]
constraints
coord:CoordValue[3]

2.1.27 objectType: ProperMotion

vodml-id ProperMotion
description Proper motion represented as the velocity in Longitude and Latitude directions of a spherical coordinate space. The associated SpaceFrame provides the details regarding the nature of the coordinate space (eg: Equatorial, Galactic, etc).
extends Velocity [meas:Velocity]
attributes
name feature value
lon type coords:Longitude
vodml-id ProperMotion.lon
multiplicity 1
description Velocity in angular distance per unit time along the Longitude axis.
lat type coords:Latitude
vodml-id ProperMotion.lat
multiplicity 1
description Velocity in angular distance per unit time along the Latitude axis.

2.1.28 dataType: Symmetrical

vodml-id Symmetrical
description Symmetrical uncertainty, constant in all dimensions and directions from the associated Coordinate. ie: PlusMinus in 1D, circular in 2D, spherical in 3D.
extends Uncertainty [meas:Uncertainty]
attributes
name feature value
radius type ivoa:RealQuantity
vodml-id Symmetrical.radius
multiplicity 1
description The uncertainty extent, constant in all dimensions and directions.

2.1.29 objectType: Time

vodml-id Time
description Provides a complete description of a measured Temporal instant.
extends Measure [meas:Measure]
attributes
name feature value
coord type coords:TimeStamp
vodml-id Time.coord
multiplicity 1
description The measured time value. May be provided in any of the TimeStamp subtypes.

2.1.30 dataType: Uncertainty

vodml-id Uncertainty
description Abstract head of uncertainty types. These classes define the shape of the uncertainty, and are designed to be reusable in different contexts. Uncertainties are designed to be associated with a Coordinate or other object which provides the 'center' or reference location about which the uncertainty resides. In this model, we use them in the context of defining measurement errors, but they are also compatible for use in defining resolutions which are to be modeled at a later date.
abstract True
Subclasses in this model Asymmetrical1D Asymmetrical2D Asymmetrical3D Bounds1D Bounds2D Bounds3D CovarianceMatrix Ellipse Ellipsoid Symmetrical

2.1.31 objectType: Velocity

vodml-id Velocity
description Provides a comple description of a measured Velocity instant.
extends Measure [meas:Measure]
abstract True
Subclasses in this model GenericVelocity ProperMotion
constraints
coordinate frames == same SpaceFrame

2.1.32 objectType: Velocity1D

vodml-id Velocity1D
description Generic 1-Dimensional velocity.
extends GenericVelocity [meas:GenericVelocity]
constraints
coord:CoordValue[1]

2.1.33 objectType: Velocity2D

vodml-id Velocity2D
description Generic 2-Dimensional velocity.
extends GenericVelocity [meas:GenericVelocity]
constraints
coord:CoordValue[2]

2.1.34 objectType: Velocity3D

vodml-id Velocity3D
description Generic 3-Dimensional velocity.
extends GenericVelocity [meas:GenericVelocity]
constraints
coord:CoordValue[3]


3.Element Identifiers/VO-DMLrefs

The following table shows all fully qualified vodml-ids for this data model. It is ordered alphabetically and the identifiers are hyper-linked to the location in the document where the actual element is fully defined.
vodml-id feature type description
vo-dml:model This model defines objects and datatypes which represent 'measured' or 'determined' data. It associates a Coordinate (ie: the determined value) with corresponding Error(s). As such, this model is at least the foundation for representing the vast majority of the Astronomical data found in catalogs and data products. We define here, several specialized classes which cover the most basic and common types, such as Position and Time. We also provide a generic model which can accommodate virtually any data, but may require a bit more effort to fully describe the coordinate metadata. Additional specializations, e.g. Flux, Magnitude, Luminosity, Pressure, Temperature, etc. may be added to this model, or in other models focusing on particular domains or use cases. We include a fairly simple Error model, describing errors as a 'shape' of uncertainty, and define a small set of commonly occuring forms (e.g. Symmetrical, Bounds, Ellipsoid).
Asymmetrical1D dataType Uncertainty with different extent in the positive and negative directions from the associated Coordinate.
Asymmetrical1D.minus attribute Extent in the negative axis direction.
Asymmetrical1D.plus attribute Extent in the positive axis direction.
Asymmetrical2D dataType 2D Uncertainty with different extent in the positive and negative axis directions from the associated Coordinate. i.e.: an offset rectangle.
Asymmetrical2D.minus attribute Extent in each negative axis direction.
Asymmetrical2D.plus attribute Extent in each positive axis direction.
Asymmetrical3D dataType 3D Uncertainty with different extent in the positive and negative axis directions from the associated Coordinate. i.e.: an offset box.
Asymmetrical3D.minus attribute Extent in each negative axis direction.
Asymmetrical3D.plus attribute Extent in each positive axis direction.
Bounds1D dataType Provide the edges of the uncertainty space. Rather than being relative to the associated Coordinate, these represent a range within that Coordinate space.
Bounds1D.hiLimit attribute Upper limit of the uncertainty range.
Bounds1D.loLimit attribute Lower limit of the uncertainty range.
Bounds2D dataType Provide the edges of a 2D uncertainty space. Rather than being relative to the associated Coordinate, these represent ranges along each axis of that Coordinate space.
Bounds2D.hiLimit attribute Upper edges of the uncertainty rectangle.
Bounds2D.loLimit attribute Lower edges of the uncertainty rectangle.
Bounds3D dataType Provide the edges of a 3D uncertainty space. Rather than being relative to the associated Coordinate, these represent ranges along each axis of that Coordinate space.
Bounds3D.hiLimit attribute Upper edges of the uncertainty box.
Bounds3D.loLimit attribute Lower edges of the uncertainty box.
CartesianPosition objectType 3-Dimensional position in an cartesian coordinate space.
CartesianPosition.x attribute X-Axis value.
CartesianPosition.y attribute Y-Axis value.
CartesianPosition.z attribute Z-Axis value.
CovarianceMatrix dataType Uncertainty expressed as a covariance matrix.
CovarianceMatrix.matrix attribute The m x m matrix, where m is the number of dimensions of the associated Coordinate.
EclipticPosition objectType 2-Dimensional position in an ecliptic coordinate space. All contained coordinates MUST be associated with the same SpaceFrame instance.
EclipticPosition.elat attribute Ecliptic Latitude. The corresponding SpaceFrame MUST specify an ecliptic reference frame, with appropriate reference position.
EclipticPosition.elon attribute Ecliptic Longitude. The corresponding SpaceFrame MUST specify an ecliptic reference frame, with appropriate reference position.
Ellipse dataType Elliptical uncertainty shape.
Ellipse.posAngle attribute Position angle, counter-clockwise from the positive direction of the first axis of the associated Coordinate.
Ellipse.semiAxis attribute Extent of the semi-major and semi-minor axes, provided in the order of the associated Coordinate axes.
Ellipsoid dataType Ellipsoidal uncertainty shape.
Ellipsoid.posAngle attribute Position angles, counter-clockwise from the positive direction of the first axis toward the second axis, and angle 'above' the plane of the first two axes of the associated Coordinate.
Ellipsoid.semiAxis attribute Extent of the semi axes, provided in the order of the associated Coordinate axes.
EquatorialPosition objectType 2-Dimensional position in an equatorial coordinate space. All contained coordinates MUST be associated with the same SpaceFrame instance.
EquatorialPosition.dec attribute Declination. The corresponding SpaceFrame MUST specify an equatorial reference frame, with appropriate reference position and equinox.
EquatorialPosition.ra attribute Right Ascension. The corresponding SpaceFrame MUST specify an equatorial reference frame, with appropriate reference position and equinox.
Error objectType The Error class uses the Uncertainty types to describe measurement errors from various sources.
Error.ranError attribute Random error. The Uncertainty type MUST be dimensionally compatible with the associated Measure value.
Error.statError attribute Statistical error. The Uncertainty type MUST be dimensionally compatible with the associated Measure value.
Error.sysError attribute Systematic error. The Uncertainty type MUST be dimensionally compatible with the associated Measure value.
GalacticPosition objectType 2-Dimensional position in an galactic coordinate space. All contained coordinates MUST be associated with the same SpaceFrame instance.
GalacticPosition.b attribute Galactic Latitude. The corresponding SpaceFrame MUST specify an galactic reference frame, with appropriate reference position.
GalacticPosition.l attribute Galactic Longitude. The corresponding SpaceFrame MUST specify an galactic reference frame, with appropriate reference position.
GenericMeasure objectType The most generic Measure class. This class may be used to represent any data not covered by the specialized cases. The coordinate value type allows for the construction of multi-dimensional values to accommodate virtually any case.
GenericMeasure.coord attribute The measured coordinate value. May be of any dimensionality (current support 1,2 and 3-dimension). For many cases, the Standard1DCoord should suffice, providing a clean and simple representation of the measured value. For other cases, users will need to provide a complete coordinate description.
GenericPosition objectType Generic positional instant, appropriate for describing positional data not covered by the specialized classes. Any concrete extension of this class MUST define a specific dimensionality for the coord attribute. We provide 1,2 and 3-dimensional classes to cover the most common cases.
GenericPosition.coord attribute The measured position value. May be given by any CoordValue type associated with a SpaceFrame.
GenericVelocity objectType Generic velocity instant, appropriate for describing velocity data not covered by the specialized classes. Any concrete extension of this class MUST define a specific dimensionality for the coord attribute. We provide 1,2 and 3-dimensional classes to cover the most common cases.
GenericVelocity.coord attribute The measured velocity value. May be given by any CoordValue type associated with a SpaceFrame.
Matrix dataType Abstract Matrix data type.
Matrix2x2 dataType 2x2 matrix data type.
Matrix2x2.m11 attribute matrix cell; i=1, j=1
Matrix2x2.m12 attribute matrix cell; i=1, j=2
Matrix2x2.m21 attribute matrix cell; i=2, j=1
Matrix2x2.m22 attribute matrix cell; i=2, j=2
Matrix3x3 dataType 3x3 matrix data type.
Matrix3x3.m11 attribute matrix cell; i=1, j=1
Matrix3x3.m12 attribute matrix cell; i=1, j=2
Matrix3x3.m13 attribute matrix cell; i=1, j=3
Matrix3x3.m21 attribute matrix cell; i=2, j=1
Matrix3x3.m22 attribute matrix cell; i=2, j=2
Matrix3x3.m23 attribute matrix cell; i=2, j=3
Matrix3x3.m31 attribute matrix cell; i=3, j=1
Matrix3x3.m32 attribute matrix cell; i=3, j=2
Matrix3x3.m33 attribute matrix cell; i=3, j=3
Measure objectType Abstract base of Measure classes, associates a 'determined value' (Coordinate) with corresponding errors. We associate the Error(s) with the full Measure, rather than the individual values, in order to support both correlated and uncorrelated errors. In many cases with multi-dimensional data, the associated errors are correlated and must be considered with the value set as a whole. One consequence of this approach is that there is a looser association between the Error dimensions and the corresponding value dimension. We require that the Error content MUST be compatible with the value dimension and nature (e.g. dimension, domain, units, etc).
Measure.error composition Measurement error.
Polarization objectType Provides a complete description of a determined polarization state. Since the polarization coordinate is an enumerated type, there can be no associated numerical error sources.
Polarization.coord attribute Determined polarization state. May be provided by any of the PolCoordValue subtypes.
Position objectType Provides a complete description of a measured positional instant.
Position1D objectType Generic 1-Dimensional position.
Position2D objectType Generic 2-Dimensional position.
Position3D objectType Generic 3-Dimensional position.
ProperMotion objectType Proper motion represented as the velocity in Longitude and Latitude directions of a spherical coordinate space. The associated SpaceFrame provides the details regarding the nature of the coordinate space (eg: Equatorial, Galactic, etc).
ProperMotion.lat attribute Velocity in angular distance per unit time along the Latitude axis.
ProperMotion.lon attribute Velocity in angular distance per unit time along the Longitude axis.
Symmetrical dataType Symmetrical uncertainty, constant in all dimensions and directions from the associated Coordinate. ie: PlusMinus in 1D, circular in 2D, spherical in 3D.
Symmetrical.radius attribute The uncertainty extent, constant in all dimensions and directions.
Time objectType Provides a complete description of a measured Temporal instant.
Time.coord attribute The measured time value. May be provided in any of the TimeStamp subtypes.
Uncertainty dataType Abstract head of uncertainty types. These classes define the shape of the uncertainty, and are designed to be reusable in different contexts. Uncertainties are designed to be associated with a Coordinate or other object which provides the 'center' or reference location about which the uncertainty resides. In this model, we use them in the context of defining measurement errors, but they are also compatible for use in defining resolutions which are to be modeled at a later date.
Velocity objectType Provides a comple description of a measured Velocity instant.
Velocity1D objectType Generic 1-Dimensional velocity.
Velocity2D objectType Generic 2-Dimensional velocity.
Velocity3D objectType Generic 3-Dimensional velocity.

4.Imported Models

This section lists the external models imported by the current data model. For each imported model we list URLs to the VO-DML and HTML representations and the prefix used for vodml-ids from inside the model.

4.1 coords

Model vodml-id coords
url https://volute.g-vo.org/svn/trunk/projects/dm/STC/Coords/vo-dml/STC_coords-v1.0.vo-dml.xml
documentation url https://volute.g-vo.org/svn/trunk/projects/dm/STC/Coords/vo-dml/STC_coords-v1.0.html

4.2 ivoa

Model vodml-id ivoa
url http://www.ivoa.net/xml/VODML/20180519/IVOA-v1.0.vo-dml.xml
documentation url http://volute.g-vo.org/svn/trunk/projects/dm/vo-dml/models/ivoa/vo-dml/IVOA-v1.0.html