<?xml version="1.0" encoding="UTF-8"?>
<vo-dml:model xmlns:vo-dml="http://www.ivoa.net/xml/VODML/v1"
              xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
              xsi:schemaLocation="http://www.ivoa.net/xml/VODML/v1 http://www.ivoa.net/xml/VODML/vo-dml-v1.xsd">
  <name>Phot</name>
  <description>Data model describing Photometric properties for data sets to be used for data calibration, comparison or reprocessing. 
</description>
  <uri/>
  <title>PhotDM</title>
  <author>Jesús Salgado, Carlos Rodrigo, Pedro Osuna, Mark Allen, Mireille Louys, Jonathan McDowell, Deborah Baines, Jesús Maíz Apellániz,
Evanthia Hatziminaoglou, Sebastien Derriere, Gerard Lemson</author>
  <version>1.1</version>
  <previousVersion>1.0</previousVersion>
  <lastModified>2022-05-20T18:03:25</lastModified>
  <import>
    <name>ivoa</name>
    <url>http://www.ivoa.net/xml/VODML/IVOA-v1.vo-dml.xml</url>
    <documentationURL>https://github.com/ivoa/vo-dml/blob/master/models/ivoa/vo-dml/IVOA-v1.0.html</documentationURL>
  </import>
  <primitiveType>
    <vodml-id>UCD</vodml-id>
    <name>UCD</name>
    <description>Specialized string type derived from ivoa:string. UCD words belong to a controlled vocabulary. They are used as semantics tags for the content of table columns . See the UCD IVOA Recommendation.
</description>
    <extends>
      <vodml-ref>ivoa:string</vodml-ref>
    </extends>
  </primitiveType>

  <primitiveType>
    <vodml-id>ISOTime</vodml-id>
    <name>ISOTime</name>
    <description>Time stamp, represented as a string. This representation is compliant to the DALI time stamp definition : section 3.3.3 Timestamp in
https://www.ivoa.net/documents/DALI/20170517/REC-DALI-1.1.pdf
This class derives from the ivoa:datetime class.

It could be inserted in the ivoa: template data model for types in a next version. </description>
    <extends>
      <vodml-ref>ivoa:datetime</vodml-ref>
    </extends>
  </primitiveType>

  <enumeration>
    <vodml-id>TypeOfMagSystem</vodml-id>
    <name>TypeOfMagSystem</name>
    <description>The type of System used to compute magnitude for this photometric calibration procedure .</description>
    <literal>
      <vodml-id>TypeOfMagSystem.VEGAmag</vodml-id>
      <name>VEGAmag</name>
      <description>Magnitude system related to VEGA.</description>
    </literal>
    <literal>
      <vodml-id>TypeOfMagSystem.ABmag</vodml-id>
      <name>ABmag</name>
      <description>AB magnitude system.</description>
    </literal>
    <literal>
      <vodml-id>TypeOfMagSystem.STmag</vodml-id>
      <name>STmag</name>
      <description>ST magnitude system.</description>
    </literal>
  </enumeration>

  <objectType>
    <vodml-id>PhotometricSystem</vodml-id>
    <name>PhotometricSystem</name>
    <description>The reference photometric system used to interpret photometric measurements.</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>PhotometricSystem.description</vodml-id>
      <name>description</name>
      <description>This string contains a human readable short-text representation of the photometric system. This will allow client applications to display textual information to final users.</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometricSystem.detectorType</vodml-id>
      <name>detectorType</name>
      <description>Detector type associated to this photometric system. Possible values are: 0 for Energy counter (amplifiers), 1 for Photon counter (CCDs, Photomultipliers).</description>
      <datatype>
        <vodml-ref>ivoa:integer</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <composition>
      <vodml-id>PhotometricSystem.photometryFilter</vodml-id>
      <name>photometryFilter</name>
      <description>The Photometric information is related to a Photometric system, and gathers filter descriptions, for one or several . 
</description>
      <datatype>
        <vodml-ref>Phot:PhotometryFilter</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>-1</maxOccurs>
      </multiplicity>
    </composition>
  </objectType>

  <objectType>
    <vodml-id>PhotometryFilter</vodml-id>
    <name>PhotometryFilter</name>
    <description>Filter class to store ids, name and properties.
</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>PhotometryFilter.fpsIdentifier</vodml-id>
      <name>fpsIdentifier</name>
      <description>IVOA identifier of the filter profile service where this photometry filter is registered to be used in the discovery of all the relevant photometry filter properties.</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometryFilter.identifier</vodml-id>
      <name>identifier</name>
      <description>This field identifies a filter, in a unique way, within a certain Photometry Filter Profile service.
Example to build this string : Facility/Subcategory/Band[/Suffix] like SDSS/SDSS.G/G</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometryFilter.name</vodml-id>
      <name>name</name>
      <description>A human readable string to represent the filter name.</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometryFilter.description</vodml-id>
      <name>description</name>
      <description>This string contains a verbose human readable label for the filter. This will allow client applications to display textual information to final users.</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometryFilter.bandName</vodml-id>
      <name>bandName</name>
      <description>A standard label representing the spectral band associated to this filter (if any).</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometryFilter.dateValidityFrom</vodml-id>
      <name>dateValidityFrom</name>
      <description>Start time of the time coverage for which this filter configuration is applicable. String time format accepted is ISO8601.
</description>
      <datatype>
        <vodml-ref>Phot:ISOTime</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>PhotometryFilter.dateValidityTo</vodml-id>
      <name>dateValidityTo</name>
      <description>End time of the time coverage for which this filter configuration is applicable. String time format accepted is ISO8601.
</description>
      <datatype>
        <vodml-ref>Phot:ISOTime</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <composition>
      <vodml-id>PhotometryFilter.bandwidth</vodml-id>
      <name>bandwidth</name>
      <description>Association to the spectral band-pass of the Filter.


</description>
      <datatype>
        <vodml-ref>Phot:Bandwidth</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
    <composition>
      <vodml-id>PhotometryFilter.transmissionCurve</vodml-id>
      <name>transmissionCurve</name>
      <description>Link to the Transmission Curve of the Filter, when this is described.</description>
      <datatype>
        <vodml-ref>Phot:TransmissionCurve</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>0</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
    <composition>
      <vodml-id>PhotometryFilter.spectralLocation</vodml-id>
      <name>spectralLocation</name>
      <description>Association to a spectral coordinate value for locating the Filter band-pass. Usually the mean value.

</description>
      <datatype>
        <vodml-ref>Phot:SpectralLocation</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
  </objectType>

  <objectType>
    <vodml-id>PhotCal</vodml-id>
    <name>PhotCal</name>
    <description>A class to bind together all  photometic calibration reference information: a photometry filter, a certain magnitude system configuration and a certain zero point object.</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>PhotCal.identifier</vodml-id>
      <name>identifier</name>
      <description>A unique identifier of the Photometry calibration instance within the project  and a filterprofile service . Suggested syntax would be:
Facility/Subcategory/Band/Photometric System Type[/Suffix]</description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <composition>
      <vodml-id>PhotCal.zeroPoint</vodml-id>
      <name>zeroPoint</name>
      <description>The ZeroPoint value for the flux to mag translation belongs to a Photcal element and is defined for one Filter element and one MagnitudeSystem .</description>
      <datatype>
        <vodml-ref>Phot:ZeroPoint</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
    <composition>
      <vodml-id>PhotCal.magnitudeSystem</vodml-id>
      <name>magnitudeSystem</name>
      <description>ZeroPoint values are given with one computation method corresponding to a defined Magnitude system.
</description>
      <datatype>
        <vodml-ref>Phot:MagnitudeSystem</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
    <reference>
      <vodml-id>PhotCal.photometryFilter</vodml-id>
      <name>photometryFilter</name>
      <description>Each PhotCal element is related to one single Filter. Some Filter object may have no calibration registered yet.</description>
      <datatype>
        <vodml-ref>Phot:PhotometryFilter</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </reference>
  </objectType>

  <objectType>
    <vodml-id>ZeroPoint</vodml-id>
    <name>ZeroPoint</name>
    <description>This class is used to characterize a zero point flux obtained during the calibration of a certain photometry filter on a certain photometric system configuration.</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>ZeroPoint.type</vodml-id>
      <name>type</name>
      <description>Type describing the way the zeropoint value is defined . Is an integer value : {0=Pogson, 1=Asinh, 2=Linear} corresponding to zero point definitions.</description>
      <datatype>
        <vodml-ref>ivoa:integer</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>ZeroPoint.referenceMagnitudeValue</vodml-id>
      <name>referenceMagnitudeValue</name>
      <description>Reference magnitude value  of the calibrating object.  can be a implemented as a  double number to get the maximum precision. 
Default value is zero, but sometimes the reference mag measured is slightly above.

</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>ZeroPoint.referenceMagnitudeError</vodml-id>
      <name>referenceMagnitudeError</name>
      <description>Total error estimated on the reference magnitude value whenever applicable. 
</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <composition>
      <vodml-id>ZeroPoint.flux</vodml-id>
      <name>flux</name>
      <description>Points to the flux value associated to this ZeroPoint magnitude.
</description>
      <datatype>
        <vodml-ref>Phot:Flux</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
  </objectType>

  <objectType>
    <vodml-id>PogsonZeropoint</vodml-id>
    <name>PogsonZeropoint</name>
    <description>Extension of ZeroPoint to accommodate standard logarithm magnitudes. It has no supplementary attributes but specific conversion functions.
</description>
    <extends>
      <vodml-ref>Phot:ZeroPoint</vodml-ref>
    </extends>
  </objectType>

  <objectType>
    <vodml-id>AsinhZeropoint</vodml-id>
    <name>AsinhZeropoint</name>
    <description>Extension of ZeroPoint to describe asinh magnitudes, a.k.a. luptitudes.</description>
    <extends>
      <vodml-ref>Phot:ZeroPoint</vodml-ref>
    </extends>
    <attribute>
      <vodml-id>AsinhZeropoint.softeningParameter</vodml-id>
      <name>softeningParameter</name>
      <description>Parameter used to correct the calculation of magnitudes for faint sources. Usually called 'b'. See (Lupton and Gunn et al. [1999]) for a formal explanation.</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

  <objectType>
    <vodml-id>LinearFluxZeropoint</vodml-id>
    <name>LinearFluxZeropoint</name>
    <description>Extension of ZeroPoint to describe simple linear flux photometry, commonly used in Radio, Far Infrared and X-ray spectral ranges. Although not being magnitudes as such, relative linear flux measurements can be included as a special and trivial case of magnitude.
</description>
    <extends>
      <vodml-ref>Phot:ZeroPoint</vodml-ref>
    </extends>
  </objectType>

  <objectType>
    <vodml-id>MagnitudeSystem</vodml-id>
    <name>MagnitudeSystem</name>
    <description>A class to describe the Magnitude System used , its type and the reference spectrum attached if present.</description>
    <attribute>
      <vodml-id>MagnitudeSystem.type</vodml-id>
      <name>type</name>
      <description>Type of magnitude system used to compute the associated zeropoint . Typical values are : VEGAmag, ABmag, STmag .
</description>
      <datatype>
        <vodml-ref>Phot:TypeOfMagSystem</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>MagnitudeSystem.referenceSpectrum</vodml-id>
      <name>referenceSpectrum</name>
      <description>Link to the reference spectrum as a URI.</description>
      <datatype>
        <vodml-ref>ivoa:anyURI</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

  <objectType>
    <vodml-id>Bandwidth</vodml-id>
    <name>Bandwidth</name>
    <description>This class is used to characterize the spectral properties of a filter. 
</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>Bandwidth.ucd</vodml-id>
      <name>ucd</name>
      <description>Unified Content Description (UCD) string that specifies the nature of the bandwidth object.</description>
      <datatype>
        <vodml-ref>Phot:UCD</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Bandwidth.unitexpression</vodml-id>
      <name>unitexpression</name>
      <description>Unit string  that specifies the spectral unit for this filter.</description>
      <datatype>
        <vodml-ref>ivoa:Unit</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Bandwidth.extent</vodml-id>
      <name>extent</name>
      <description>Bandwidth’s extent of the filter , as length of the covered spectral interval , or effective width following appropriate filter type.
</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>0</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Bandwidth.start</vodml-id>
      <name>start</name>
      <description>In practice, this could be taken as the minimum value of the filter transmission curve.</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Bandwidth.stop</vodml-id>
      <name>stop</name>
      <description>In practice, this could be taken as the maximum value of the filter transmission curve.</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

  <objectType>
    <vodml-id>TransmissionPoint</vodml-id>
    <name>TransmissionPoint</name>
    <description>This class is used to represent a point in the transmission function of a Filter.

</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>TransmissionPoint.transmissionValue</vodml-id>
      <name>transmissionValue</name>
      <description>Transmitted value for the filter at this point of the transmission curve. Usually between 0 and 1. 
</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>TransmissionPoint.spectralValue</vodml-id>
      <name>spectralValue</name>
      <description>Spectral coordinate value for the transmission point.</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>TransmissionPoint.spectralErrorValue</vodml-id>
      <name>spectralErrorValue</name>
      <description>Error on the spectral coordinate value for the transmission point.</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>0</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>TransmissionPoint.ucd</vodml-id>
      <name>ucd</name>
      <description>Unified Content Description (UCD) string that specifies the nature of the spectral axis in the transmission curve.</description>
      <datatype>
        <vodml-ref>Phot:UCD</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>TransmissionPoint.unit</vodml-id>
      <name>unit</name>
      <description>Unit string  that specifies the spectral unit for this filter.</description>
      <datatype>
        <vodml-ref>ivoa:Unit</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

  <objectType>
    <vodml-id>Access</vodml-id>
    <name>Access</name>
    <description>Gathers all properties to access a resource : uri, format and size . 
</description>
    <attribute>
      <vodml-id>Access.reference</vodml-id>
      <name>reference</name>
      <description>URI to access the resource.</description>
      <datatype>
        <vodml-ref>ivoa:anyURI</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Access.size</vodml-id>
      <name>size</name>
      <description>Approximate estimated size of the dataset, specified in kilobytes.</description>
      <datatype>
        <vodml-ref>ivoa:integer</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Access.format</vodml-id>
      <name>format</name>
      <description>Format of the accessed resource.  Typically a MIME type is used : application/fits, application/x-votable+xml, text/csv, text/xml, etc. </description>
      <datatype>
        <vodml-ref>ivoa:string</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

  <objectType>
    <vodml-id>TransmissionCurve</vodml-id>
    <name>TransmissionCurve</name>
    <description>A collection of points along the spectral axis to indicate how flux are transmitted by a filter. 
The transmission profile can be described by an external file and accessed through the Access instance, or can be stored as a collection of transmission points stored together in the PhotometryFilter serialized instance.</description>
    <composition>
      <vodml-id>TransmissionCurve.transmissionPoint</vodml-id>
      <name>transmissionPoint</name>
      <description>Set of points of the transmission curve.</description>
      <datatype>
        <vodml-ref>Phot:TransmissionPoint</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>-1</maxOccurs>
      </multiplicity>
    </composition>
    <composition>
      <vodml-id>TransmissionCurve.access</vodml-id>
      <name>access</name>
      <description>Access to an external file containing the set of Transmission Points.</description>
      <datatype>
        <vodml-ref>Phot:Access</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>0</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </composition>
  </objectType>

  <objectType>
    <vodml-id>SpectralLocation</vodml-id>
    <name>SpectralLocation</name>
    <description>A spectral coordinate value for locating the Filter band-pass. Usually the mean  value (for instance in wavelength units).
This class is used to characterize the spectral properties of a filter. 
</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>SpectralLocation.ucd</vodml-id>
      <name>ucd</name>
      <description>Unified Content Description (UCD) string that specifies the nature of the spectral location for this filter.</description>
      <datatype>
        <vodml-ref>Phot:UCD</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>SpectralLocation.unitexpression</vodml-id>
      <name>unitexpression</name>
      <description>Unit string  that specifies the spectral units for this filter.</description>
      <datatype>
        <vodml-ref>ivoa:Unit</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>SpectralLocation.value</vodml-id>
      <name>value</name>
      <description>A spectral coordinate value that can be considered by the data provider as the most representative for this specific filter bandpass. 
In the Optical regime this can represent the effective wavelength, for instance.
</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

  <objectType>
    <vodml-id>Flux</vodml-id>
    <name>Flux</name>
    <description>This class is used to characterize the photometric calibration  Flux&lt;—&gt; Magnitude associated to the ZeroPoint used by a PhotCal instance.
</description>
    <constraint>
      <description>One association at the time
</description>
    </constraint>
    <attribute>
      <vodml-id>Flux.ucd</vodml-id>
      <name>ucd</name>
      <description>Unified Content Description (UCD) string that specifies the nature of the flux.
</description>
      <datatype>
        <vodml-ref>Phot:UCD</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Flux.unitexpression</vodml-id>
      <name>unitexpression</name>
      <description>Unit string  that specifies the flux unit.
</description>
      <datatype>
        <vodml-ref>ivoa:Unit</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Flux.value</vodml-id>
      <name>value</name>
      <description>A flux value.</description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
    <attribute>
      <vodml-id>Flux.error</vodml-id>
      <name>error</name>
      <description>Flux value error corresponding to the reference magnitude value  of the calibrating object. </description>
      <datatype>
        <vodml-ref>ivoa:real</vodml-ref>
      </datatype>
      <multiplicity>
        <minOccurs>1</minOccurs>
        <maxOccurs>1</maxOccurs>
      </multiplicity>
    </attribute>
  </objectType>

</vo-dml:model>