<?xml version="1.0" encoding="UTF-8"?>
  <!-- PDS4 XML/Schema for Name Space Id:sp  Version:1.3.0.0 - Thu Aug 13 10:28:15 EDT 2020 -->
  <!-- Generated from the PDS4 Information Model Version 1.14.0.0 - System Build 10b -->
  <!-- *** This PDS4 product schema is an operational deliverable. *** -->
  <!--                                                                           -->
  <!--               Dictionary Stack                                            -->
  <!-- 1.14.0.0 - pds: - Common Dictionary                                       -->
  <!-- 1.3.0.0 - sp: - Spectral Discipline Dictionary                            -->
  <!--   file:SpectraLDD-1E00_1300.xml                                           -->
  <!--                                                                           -->
  <xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema"
    targetNamespace="http://pds.nasa.gov/pds4/sp/v1"
    xmlns:sp="http://pds.nasa.gov/pds4/sp/v1"
    xmlns:pds="http://pds.nasa.gov/pds4/pds/v1"
    elementFormDefault="qualified"
    attributeFormDefault="unqualified"
    version="1.3.0.0">
 
    <xs:import namespace="http://pds.nasa.gov/pds4/pds/v1" schemaLocation="https://pds.nasa.gov/pds4/pds/v1/PDS4_PDS_1E00.xsd"/>
 
  <xs:annotation>
    <xs:documentation>

        This is a complete re-write of the Spectral Dictionary version 1.1.0.0  (i.e., PDS4_SP_1100, 
        released with core IM 1.4.0.0) to bring it into compliance with requirements and best practices 
        established since the original version was created.  
        
        Existing attribute definitions have been reviewed and in some cases updated.  This should be 
        reflected in the version_id value of the attribute.
        
        The "submitter_name" of "ACR" indicates Anne (C.) Raugh.
        
        Modification History:
        
           2018-05-25  ACR  Version 1.0.0.0  First release
           
           2018-11-02  ACR  Version 1.1.0.0  Added support for tabulated spectra
           2019-03-08  ACR  Version 1.1.0.0  Replaced "data()" with equivalent "data(.)" to work around
                                             a Validate Tool issue
           2019-03-15  ACR  Version 1.1.0.0  Fixed bug in range checking for Uniformly Sampled data by
                                             adding "number()" function
           2019-07-29  ACR  Version 1.2.0.0  Added table support for rows and fields in Uniformly_Sampled;
                                             Moved Bin_Width_Constant class (unusable as designed) into Spectral_Lookup;
                                             Made bin-width nillable for cases where it is unknown;
                                             Removed references to "original bin number" (mission-specific);
                                             Expanded Axis_Bin_Set class for tabular (row and field) spectra 
           2020-08-05  ACR  Version 1.3.0.0  Added support for X-ray spectra with energy bins; minor changes to 
                                             Ingest_LDD.
    
    </xs:documentation>
  </xs:annotation>
 
  <xs:element name="Spectral_Characteristics" type="sp:Spectral_Characteristics"> </xs:element>

  <xs:complexType name="Axis_Bin_Set_Energy">
    <xs:annotation>
      <xs:documentation> The Axis_Bin_Set_* classes describe the
        spectral characteristics of each band along the spectral
        dimension of the data object. This will be a literal "axis" in
        the case of 2D and 3D spectral arrays, or the "Row" axis of a
        spectral table (each row is a spectral bin), or the "Field" axis
        of table containing one spectrum per row. These classes are used
        in cases where the spectral information is not uniform along the
        spectral dimension. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="Bin_Energy" type="sp:Bin_Energy" minOccurs="1" maxOccurs="unbounded"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Axis_Bin_Set_Frequency">
    <xs:annotation>
      <xs:documentation> The Axis_Bin_Set_* classes describe the
        spectral characteristics of each band along the spectral
        dimension of the data object. This will be a literal "axis" in
        the case of 2D and 3D spectral arrays, or the "Row" axis of a
        spectral table (each row is a spectral bin), or the "Field" axis
        of table containing one spectrum per row. These classes are used
        in cases where the spectral information is not uniform along the
        spectral dimension. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="Bin_Frequency" type="sp:Bin_Frequency" minOccurs="1" maxOccurs="unbounded"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Axis_Bin_Set_Wavelength">
    <xs:annotation>
      <xs:documentation> The Axis_Bin_Set_* classes describe the
        spectral characteristics of each band along the spectral
        dimension of the data object. This will be a literal "axis" in
        the case of 2D and 3D spectral arrays, or the "Row" axis of a
        spectral table (each row is a spectral bin), or the "Field" axis
        of table containing one spectrum per row. These classes are used
        in cases where the spectral information is not uniform along the
        spectral dimension. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="Bin_Wavelength" type="sp:Bin_Wavelength" minOccurs="1" maxOccurs="unbounded"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Axis_Bin_Set_Wavenumber">
    <xs:annotation>
      <xs:documentation> The Axis_Bin_Set_* classes describe the
        spectral characteristics of each band along the spectral
        dimension of the data object. This will be a literal "axis" in
        the case of 2D and 3D spectral arrays, or the "Row" axis of a
        spectral table (each row is a spectral bin), or the "Field" axis
        of table containing one spectrum per row. These classes are used
        in cases where the spectral information is not uniform along the
        spectral dimension. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="Bin_Wavenumber" type="sp:Bin_Wavenumber" minOccurs="1" maxOccurs="unbounded"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Center_Lookup">
    <xs:annotation>
      <xs:documentation> The Bin_Center_Lookup class provides a link to
        a map or list of bin center values - either to a field in a
        spectral table, or to a distinct data object that is part of the
        same product, or to a separate PDS product containing the
        information. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_center_field_name" type="sp:bin_center_field_name" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="bin_center_field_number_list" type="sp:bin_center_field_number_list" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element ref="pds:Local_Internal_Reference" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element ref="pds:Internal_Reference" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Description">
    <xs:annotation>
      <xs:documentation> This class groups the various bin description
        options, allowing a user to choose one. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_profile_description" type="sp:bin_profile_description" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:choice minOccurs="1" maxOccurs="1">
        <xs:element name="Uniformly_Sampled_Frequency" type="sp:Uniformly_Sampled_Frequency"> </xs:element>
        <xs:element name="Uniformly_Sampled_Wavelength" type="sp:Uniformly_Sampled_Wavelength"> </xs:element>
        <xs:element name="Uniformly_Sampled_Wavenumber" type="sp:Uniformly_Sampled_Wavenumber"> </xs:element>
        <xs:element name="Axis_Bin_Set_Frequency" type="sp:Axis_Bin_Set_Frequency"> </xs:element>
        <xs:element name="Axis_Bin_Set_Wavelength" type="sp:Axis_Bin_Set_Wavelength"> </xs:element>
        <xs:element name="Axis_Bin_Set_Wavenumber" type="sp:Axis_Bin_Set_Wavenumber"> </xs:element>
        <xs:element name="Spectral_Lookup" type="sp:Spectral_Lookup"> </xs:element>
      </xs:choice>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Energy">
    <xs:annotation>
      <xs:documentation> The Bin_Energy class specifies the
        characteristics of an individual bin along a spectral or other
        binned axis in an Array object, in units of energy.
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_sequence_number" type="sp:bin_sequence_number" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="center_energy" type="sp:center_energy" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_energy" nillable="true" type="sp:bin_width_energy" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="detector_number" type="sp:detector_number" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="grating_position" type="sp:grating_position" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="Filter" type="sp:Filter" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Frequency">
    <xs:annotation>
      <xs:documentation> The Bin_Frequency class specifies the
        characteristics of an individual bin along a spectral or other
        binned axis in an Array object, in units of frequency.
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_sequence_number" type="sp:bin_sequence_number" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="center_frequency" type="sp:center_frequency" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_frequency" nillable="true" type="sp:bin_width_frequency" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="detector_number" type="sp:detector_number" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="grating_position" type="sp:grating_position" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="Filter" type="sp:Filter" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Wavelength">
    <xs:annotation>
      <xs:documentation> The Bin_Wavelength class specifies the
        characteristics of an individual bin along a spectral or other
        binned axis in an Array object, in units of wavelength.
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_sequence_number" type="sp:bin_sequence_number" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="center_wavelength" type="sp:center_wavelength" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_wavelength" nillable="true" type="sp:bin_width_wavelength" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="detector_number" type="sp:detector_number" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="grating_position" type="sp:grating_position" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="Filter" type="sp:Filter" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Wavenumber">
    <xs:annotation>
      <xs:documentation> The Bin_Wavenumber class specifies the
        characteristics of an individual bin along a spectral or other
        binned axis in an Array object, in units of wavenumber.
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_sequence_number" type="sp:bin_sequence_number" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="center_wavenumber" type="sp:center_wavenumber" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_wavenumber" nillable="true" type="sp:bin_width_wavenumber" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="detector_number" type="sp:detector_number" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="grating_position" type="sp:grating_position" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="Filter" type="sp:Filter" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Width_Constant">
    <xs:annotation>
      <xs:documentation> The Bin_Width_Constant class is used inside a
        Bin_Width_Lookup class for those cases where the bin width is
        either not well known or unknown. It provides a way to specify a
        nominal constant width or indicate that there is no available
        information about the bin width. If the bin width is completely
        unknown, use the appropriate bin_width attribute for the
        spectral type (frequency, wavelength, wavenumber, or energy),
        and indicate that it is nil, with a reason of "unknown". When
        this class is used, a full explanation of the situation should
        be provided by the bin_width_desc attribute of the parent class.
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:choice minOccurs="1" maxOccurs="1">
        <xs:element name="bin_width_energy" nillable="true" type="sp:bin_width_energy"> </xs:element>
        <xs:element name="bin_width_frequency" nillable="true" type="sp:bin_width_frequency"> </xs:element>
        <xs:element name="bin_width_wavelength" nillable="true" type="sp:bin_width_wavelength"> </xs:element>
        <xs:element name="bin_width_wavenumber" nillable="true" type="sp:bin_width_wavenumber"> </xs:element>
      </xs:choice>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Bin_Width_Lookup">
    <xs:annotation>
      <xs:documentation> The Bin_Width_Lookup class provides a link to a
        map or list of bin width values - either to a field in a
        spectral table, or to a distinct data object that is part of the
        same product, or to a separate PDS product containing the
        information. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="bin_width_field_name" type="sp:bin_width_field_name" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_field_number_list" type="sp:bin_width_field_number_list" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element ref="pds:Local_Internal_Reference" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element ref="pds:Internal_Reference" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Circular_FOV">
    <xs:annotation>
      <xs:documentation> The Circular_FOV class contains attributes to
        describe a circular aperture/field of view. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="diameter_angle" nillable="true" type="sp:diameter_angle" minOccurs="1" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Complex_FOV">
    <xs:annotation>
      <xs:documentation> The Complex_FOV class is used for apertures
        (slits) that are not either circular or a simple rectangular
        shape. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="width_angle" nillable="true" type="sp:width_angle" minOccurs="0" maxOccurs="unbounded"> </xs:element>
      <xs:element name="length_angle" nillable="true" type="sp:length_angle" minOccurs="0" maxOccurs="unbounded"> </xs:element>
      <xs:element name="celestial_north_position_angle" type="sp:celestial_north_position_angle" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="body_positive_pole_position_angle" type="sp:body_positive_pole_position_angle" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Field_of_View">
    <xs:annotation>
      <xs:documentation> The Field_of_View class is used to describe the
        field of view corresponding to the spectral data object. This
        class should describe the aperture or slit used in making the
        spectral observation, when applicable, as opposed to the
        theoretical full field of view of a telescope or boresight
        (which should be defined in a Geometry Dictionary class).
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="description" type="sp:description" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:choice minOccurs="1" maxOccurs="1">
        <xs:element name="Circular_FOV" type="sp:Circular_FOV"> </xs:element>
        <xs:element name="Rectangular_FOV" type="sp:Rectangular_FOV"> </xs:element>
        <xs:element name="Complex_FOV" type="sp:Complex_FOV"> </xs:element>
      </xs:choice>
      <xs:element ref="pds:Internal_Reference" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Filter">
    <xs:annotation>
      <xs:documentation> The Filter class identifies the filter
        associated with a specific band or bin along a spectral axis in
        an Array object. The filter may be identified by either name,
        identifier, or number or some combination of these.
        </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="filter_name" type="sp:filter_name" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="filter_number" type="sp:filter_number" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Observation_Parameters">
    <xs:annotation>
      <xs:documentation> The Observation_Parameters class collects
        various values related to the observational circumstances. In
        general, this class should be present, and all parameters
        applicable to the situation should be included, even though
        optional. In some complex cases or for high-level derived
        products this class may not be applicable, in which case it may
        be omitted. Use the 'comment' attribute to describe any special
        circumstances users should be aware of. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="number_of_exposures" type="sp:number_of_exposures" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="net_integration_time" type="sp:net_integration_time" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:choice minOccurs="0" maxOccurs="1">
        <xs:element name="resolution_limit_energy" type="sp:resolution_limit_energy"> </xs:element>
        <xs:element name="resolution_limit_frequency" type="sp:resolution_limit_frequency"> </xs:element>
        <xs:element name="resolution_limit_wavelength" type="sp:resolution_limit_wavelength"> </xs:element>
        <xs:element name="resolution_limit_wavenumber" type="sp:resolution_limit_wavenumber"> </xs:element>
      </xs:choice>
      <xs:element name="solar_analog_star_name" type="sp:solar_analog_star_name" minOccurs="0" maxOccurs="unbounded"> </xs:element>
      <xs:element name="absolute_calibration_star_name" type="sp:absolute_calibration_star_name" minOccurs="0" maxOccurs="unbounded"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Rectangular_FOV">
    <xs:annotation>
      <xs:documentation> This class is used to describe a rectangular
        (i.e., slit) aperture. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="width_angle" nillable="true" type="sp:width_angle" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="length_angle" nillable="true" type="sp:length_angle" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="celestial_north_position_angle" type="sp:celestial_north_position_angle" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="body_positive_pole_position_angle" type="sp:body_positive_pole_position_angle" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Spectral_Characteristics">
    <xs:annotation>
      <xs:documentation> The Spectral_Characteristics class provides
        information about the spectral characteristics of a 1D, 2D, or
        3D spectral data object. It is note used for tabulated spectra -
        tables in which each row </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element ref="pds:Local_Internal_Reference" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="description" type="sp:description" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="spectrum_format" type="sp:spectrum_format" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="value_field_name" type="sp:value_field_name" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="value_field_number_list" type="sp:value_field_number_list" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="spectral_bin_type" type="sp:spectral_bin_type" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="Observation_Parameters" type="sp:Observation_Parameters" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="Field_of_View" type="sp:Field_of_View" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="Bin_Description" type="sp:Bin_Description" minOccurs="1" maxOccurs="1"> </xs:element>
    </xs:sequence>
    <!-- Begin assert statements for schematron - Enumerated Values -->
    <!-- <xs:assert test="sp:spectrum_format = ('1D', '2D', '3D', 'Tabulated-Flat', 'Tabulated-Parameter Groups', 'Tabulated-Point Group')"/> -->
    <!-- <xs:assert test="sp:spectral_bin_type = ('energy', 'frequency', 'wavelength', 'wavenumber')"/> -->
    <!-- End assert statements for schematron - Enumerated Values -->
  </xs:complexType>

  <xs:complexType name="Spectral_Lookup">
    <xs:annotation>
      <xs:documentation> The Spectral_Lookup class references either
        specific Fields included in a spectral table (for 1D and
        tabulated spectra), or a 2-dimensional lookup map providing
        spectral characteristics for a corresponding spectral Array
        object. In the latter case, the referenced lookup map may either
        be to the referencing product, or an external stand-alone
        product. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="Bin_Center_Lookup" type="sp:Bin_Center_Lookup" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:choice minOccurs="1" maxOccurs="1">
        <xs:element name="Bin_Width_Lookup" type="sp:Bin_Width_Lookup"> </xs:element>
        <xs:element name="Bin_Width_Constant" type="sp:Bin_Width_Constant"> </xs:element>
      </xs:choice>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
  </xs:complexType>

  <xs:complexType name="Uniformly_Sampled_Energy">
    <xs:annotation>
      <xs:documentation> The Uniformly_Sampled_Energy class provides
        attributes describing the spectral characteristics of a named
        axis of an Array object or the rows or fields of a Table object,
        in cases where the spectral sampling interval is regular and the
        sampling parameters are in energy units. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_interval_energy" type="sp:sampling_interval_energy" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_scale" type="sp:sampling_scale" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_base" type="sp:sampling_base" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_energy" nillable="true" type="sp:bin_width_energy" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="first_center_energy" type="sp:first_center_energy" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="last_center_energy" type="sp:last_center_energy" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
    <!-- Begin assert statements for schematron - Enumerated Values -->
    <!-- <xs:assert test="sp:sampling_scale = ('Linear', 'Logarithmic')"/> -->
    <!-- End assert statements for schematron - Enumerated Values -->
  </xs:complexType>

  <xs:complexType name="Uniformly_Sampled_Frequency">
    <xs:annotation>
      <xs:documentation> The Uniformly_Sampled_Frequency class provides
        attributes describing the spectral characteristics of a named
        axis of an Array object or the rows or fields of a Table object,
        in cases where the spectral sampling interval is regular and the
        sampling parameters are in frequency units. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_interval_frequency" type="sp:sampling_interval_frequency" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_scale" type="sp:sampling_scale" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_base" type="sp:sampling_base" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_frequency" nillable="true" type="sp:bin_width_frequency" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="first_center_frequency" type="sp:first_center_frequency" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="last_center_frequency" type="sp:last_center_frequency" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
    <!-- Begin assert statements for schematron - Enumerated Values -->
    <!-- <xs:assert test="sp:sampling_scale = ('Linear', 'Logarithmic')"/> -->
    <!-- End assert statements for schematron - Enumerated Values -->
  </xs:complexType>

  <xs:complexType name="Uniformly_Sampled_Wavelength">
    <xs:annotation>
      <xs:documentation> The Uniformly_Sampled_Wavelength class provides
        attributes describing the spectral characteristics of a named
        axis of an Array object or the rows or fields of a Table object,
        in cases where the spectral sampling interval is regular and the
        sampling parameters are in wavelength units. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_interval_wavelength" type="sp:sampling_interval_wavelength" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_scale" type="sp:sampling_scale" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_base" type="sp:sampling_base" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_wavelength" nillable="true" type="sp:bin_width_wavelength" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="first_center_wavelength" type="sp:first_center_wavelength" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="last_center_wavelength" type="sp:last_center_wavelength" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
    <!-- Begin assert statements for schematron - Enumerated Values -->
    <!-- <xs:assert test="sp:sampling_scale = ('Linear', 'Logarithmic')"/> -->
    <!-- End assert statements for schematron - Enumerated Values -->
  </xs:complexType>

  <xs:complexType name="Uniformly_Sampled_Wavenumber">
    <xs:annotation>
      <xs:documentation> The Uniformly_Sampled_Wavenumber class provides
        attributes describing the spectral characteristics of a named
        axis of an Array object or the rows or fields of a Table object,
        in cases where the spectral sampling interval is regular and the
        sampling parameters are in wavenumber units. </xs:documentation>
    </xs:annotation>
    <xs:sequence>
      <xs:element name="axis_name" type="sp:axis_name" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_interval_wavenumber" type="sp:sampling_interval_wavenumber" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_scale" type="sp:sampling_scale" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="sampling_base" type="sp:sampling_base" minOccurs="0" maxOccurs="1"> </xs:element>
      <xs:element name="bin_width_wavenumber" nillable="true" type="sp:bin_width_wavenumber" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="first_center_wavenumber" type="sp:first_center_wavenumber" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="last_center_wavenumber" type="sp:last_center_wavenumber" minOccurs="1" maxOccurs="1"> </xs:element>
      <xs:element name="comment" type="sp:comment" minOccurs="0" maxOccurs="1"> </xs:element>
    </xs:sequence>
    <!-- Begin assert statements for schematron - Enumerated Values -->
    <!-- <xs:assert test="sp:sampling_scale = ('Linear', 'Logarithmic')"/> -->
    <!-- End assert statements for schematron - Enumerated Values -->
  </xs:complexType>

    <xs:annotation>
      <xs:documentation>This section contains the simpleTypes that provide more constraints
        than those at the base data type level. The simpleTypes defined here build on the base data
        types. This is another component of the common dictionary and therefore falls within the
        common namespace.
      </xs:documentation>
    </xs:annotation>

  <xs:simpleType name="absolute_calibration_star_name">
    <xs:annotation>
      <xs:documentation> The absolute_calibration_star_name attribute
        provides a name in a standard format (i.e., one that is
        recognized by the SIMBAD system) for the star used to reduce the
        raw spectral data to the units presented in this spectrum. This
        is the analog to solar_calibration_star_name for non-reflectance
        spectra. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:UTF8_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="axis_name">
    <xs:annotation>
      <xs:documentation> The axis_name attribute contains a string that
        matches the axis_name attribute in the associated array-type
        spectrum object; or the special values "Field" and "Row" for
        tabular and tabulated spectra. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_center_field_name">
    <xs:annotation>
      <xs:documentation> The bin_center_field_name must contain the
        value of a 'name' attribute of a Field defined in the referenced
        Table object. This named Field contains the bin center
        information for each row in a 1D spectrum presented in tabular
        form. It will have units (and possibly offset and scaling
        factor) as indicated in the Field definition. This will usually
        be accompanied by a bin_width_field_name. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_center_field_number_list">
    <xs:annotation>
      <xs:documentation> The bin_center_field_number_list attribute is
        used only in the case of spectra in the format "Tabulated-Flat",
        where each row of a table contains a spectrum and the spectral
        points are defined as individual Fields - one Field defined for
        each point. The format is a parenthesized, ordered list of the
        field_number values from the Field definitions that correspond
        to the bin center values. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
    	<xs:pattern value='\(\s*[0-9]+(\s*,\s*[0-9]+)*\s*\)'/>
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_profile_description">
    <xs:annotation>
      <xs:documentation> The bin_profile_description attributes provides
        a text description of the method used to determine or otherwise
        define the bin widths following. The description should include
        information on the shape (e.g. gaussian, square wave, etc.) and
        what the bin_width value means (i.e., standard deviation of a
        gaussian function or full-width at half max (FWHM)).
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:UTF8_Text_Preserved">
     <xs:minLength value="1"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_sequence_number">
    <xs:annotation>
      <xs:documentation> The bin_sequence_number provides the sequential
        numbering of bins along an axis in an Array object.
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_NonNegative_Integer">
    	<xs:pattern value='[0-9]+'/>
     <xs:minInclusive value="0"/>
     <xs:maxInclusive value="18446744073709551615"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_width_energy_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="bin_width_energy">
    <xs:annotation>
      <xs:documentation> The bin_width_energy attribute provides the
        width of a bin along a spectral axis in a spectral object, in
        energy units. The method used to calculate the width must be
        specified using the bin_profile_description attribute. This
        attribute can be set to 'nil' if bin widths are unknown.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:bin_width_energy_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Energy" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="bin_width_field_name">
    <xs:annotation>
      <xs:documentation> The bin_width_field_name must contain the value
        of a 'name' attribute of a Field defined in the referenced Table
        object. This named Field contains the bin width information for
        each row in a 1D spectrum presented in tabular form. It will
        have units (and possibly offset and scaling factor) as indicated
        in the Field definition. This attribute must be accompanied by a
        bin_center_field_name. If bin widths are constant or unknown,
        use the Bin_Width_Constant class to specify this.
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_width_field_number_list">
    <xs:annotation>
      <xs:documentation> The bin_width_field_number_list attribute is
        used only in the case of spectra in the format "Tabulated-Flat",
        where each row of a table contains a spectrum and the spectral
        points are defined as individual Fields - one Field defined for
        each point. The format is a parenthesized, ordered list of the
        field_number values from the Field definitions that correspond
        to the bin width values. If bin widths are constant or unknown,
        use the Bin_Width_Constant class to specify this.
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
    	<xs:pattern value='\(\s*[0-9]+(\s*,\s*[0-9]+)*\s*\)'/>
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="bin_width_frequency_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="bin_width_frequency">
    <xs:annotation>
      <xs:documentation> The bin_width_frequency attribute provides the
        width of a bin along a spectral axis in a spectral object, in
        frequency units. The method used to calculate the width must be
        specified using the bin_profile_description attribute. This
        attribute can be set to 'nil' if bin widths are unknown.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:bin_width_frequency_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Frequency" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="bin_width_wavelength_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="bin_width_wavelength">
    <xs:annotation>
      <xs:documentation> The bin_width_wavelength attribute provides the
        width of a bin along a spectral axis in a spectral object, in
        wavelength units. The method used to calculate the width must be
        specified using the bin_profile_description attribute. This
        attribute can be set to 'nil' if bin widths are unknown.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:bin_width_wavelength_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Length" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="bin_width_wavenumber_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="bin_width_wavenumber">
    <xs:annotation>
      <xs:documentation> The bin_width_wavenumber attribute provides the
        width of a bin along a spectral axis in a spectral object, in
        wavenumber units. The method used to calculate the width must be
        specified using the bin_profile_description attribute. This
        attribute can be set to 'nil' if bin widths are unknown.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:bin_width_wavenumber_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Wavenumber" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="body_positive_pole_position_angle_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="0.0"/>
     <xs:maxInclusive value="180.0"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="body_positive_pole_position_angle">
    <xs:annotation>
      <xs:documentation> The body_positive_pole_position_angle attribute
        provides the angle the long axis of the slit makes with respect
        to the positive (or "north") pole of the target body, measured
        clockwise from the pole in the range 0-180 degrees.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:body_positive_pole_position_angle_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Angle" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="celestial_north_position_angle_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="0.0"/>
     <xs:maxInclusive value="180.0"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="celestial_north_position_angle">
    <xs:annotation>
      <xs:documentation> The celestial_north_position_angle attribute
        provides the angle the long axis of the slit makes with respect
        to celestial north, measured eastward of celestial north in the
        range 0-180 degrees. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:celestial_north_position_angle_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Angle" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="center_energy_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="center_energy">
    <xs:annotation>
      <xs:documentation> The center_energy attribute provides the value
        at the center of a bin along the band axis of a spectral data
        object. When describing data from a spectrometer, the value
        corresponds to the peak of the response function for a
        particular detector and/or grating. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:center_energy_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Energy" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="center_frequency_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="center_frequency">
    <xs:annotation>
      <xs:documentation> The center_frequency attribute provides the
        value at the center of a bin along the band axis of a spectral
        data object. When describing data from a spectrometer, the value
        corresponds to the peak of the response function for a
        particular detector and/or grating. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:center_frequency_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Frequency" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="center_wavelength_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="center_wavelength">
    <xs:annotation>
      <xs:documentation> The center_wavelength attribute provides the
        value at the center of a bin along the band axis of a spectral
        data object. When describing data from a spectrometer, the value
        corresponds to the peak of the response function for a
        particular detector and/or grating. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:center_wavelength_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Length" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="center_wavenumber_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="center_wavenumber">
    <xs:annotation>
      <xs:documentation> The center_wavenumber attribute provides the
        value at the center of a bin along the band axis of a spectral
        data object. When describing data from a spectrometer, the value
        corresponds to the peak of the response function for a
        particular detector and/or grating. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:center_wavenumber_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Wavenumber" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="comment">
    <xs:annotation>
      <xs:documentation> The comment attribute is an unlimited length,
        format-preserved, UTF-8 text field for comments relevant to the
        context in which it appears. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:UTF8_Text_Preserved">
     <xs:minLength value="1"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="description">
    <xs:annotation>
      <xs:documentation> The description attribute is an unlimited
        length, format-preserved, UTF-8 text field used specifically for
        description of circumstances related to the data product of
        which a user should be aware and might logically expect to find
        in the label. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:UTF8_Text_Preserved">
     <xs:minLength value="1"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="detector_number">
    <xs:annotation>
      <xs:documentation> The detector_number attribute provides the
        spectrometer detector number corresponding to a band of a
        spectral qube. Detector numbers are usually assigned
        consecutively from 1, in order of increasing wavelength.
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_NonNegative_Integer">
    	<xs:pattern value='[0-9]+'/>
     <xs:minInclusive value="1"/>
     <xs:maxInclusive value="18446744073709551615"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="diameter_angle_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="diameter_angle">
    <xs:annotation>
      <xs:documentation> The diameter_angle attribute provides the angle
        subtended on the sky by the diameter of a circular aperture.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:diameter_angle_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Angle" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="filter_name">
    <xs:annotation>
      <xs:documentation> The filter_name attribute provides the
        commonly-used name of the instrument filter through which an
        image or measurement was acquired or which is associated with a
        given instrument mode. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="filter_number">
    <xs:annotation>
      <xs:documentation> The filter_number attribute provides the
        numeric identifier of an instrument filter through which an
        image or measurement was acquired or which is associated with a
        given instrument mode. Within the bin class of a spectral data
        object, it identifies the filter through which data in the given
        band were acquired. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_NonNegative_Integer">
    	<xs:pattern value='[0-9]+'/>
     <xs:minInclusive value="0"/>
     <xs:maxInclusive value="18446744073709551615"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="first_center_energy_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="first_center_energy">
    <xs:annotation>
      <xs:documentation> The first_center_energy attribute provides the
        value at the center of the first bin along the spectral axis of
        a spectral data object in energy units. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:first_center_energy_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Energy" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="first_center_frequency_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="first_center_frequency">
    <xs:annotation>
      <xs:documentation> The first_center_frequency attribute provides
        the value at the center of the first bin along the spectral axis
        of a spectral data object in frequency units. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:first_center_frequency_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Frequency" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="first_center_wavelength_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="first_center_wavelength">
    <xs:annotation>
      <xs:documentation> The first_center_wavelength attribute provides
        the value at the center of the first bin along the spectral axis
        of a spectral data object in wavelength units.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:first_center_wavelength_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Length" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="first_center_wavenumber_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="first_center_wavenumber">
    <xs:annotation>
      <xs:documentation> The first_center_wavenumber attribute provides
        the value at the center of the first bin along the spectral axis
        of a spectral data object in wavenumber units.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:first_center_wavenumber_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Wavenumber" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="grating_position">
    <xs:annotation>
      <xs:documentation> The grating_position attribute of a spectral
        cube describes the grating position which corresponds to the
        band. Grating positions are usually assigned consecutively from
        0, and increasing position causes increasing wavelength for each
        detector. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_NonNegative_Integer">
    	<xs:pattern value='[0-9]+'/>
     <xs:minInclusive value="0"/>
     <xs:maxInclusive value="18446744073709551615"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="last_center_energy_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="last_center_energy">
    <xs:annotation>
      <xs:documentation> The last_center_energy attribute provides the
        value at the center of the last bin along the spectral axis of a
        spectral data object in energy units. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:last_center_energy_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Energy" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="last_center_frequency_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="last_center_frequency">
    <xs:annotation>
      <xs:documentation> The last_center_frequency attribute provides
        the value at the center of the last bin along the spectral axis
        of a spectral data object in frequency units. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:last_center_frequency_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Frequency" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="last_center_wavelength_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="last_center_wavelength">
    <xs:annotation>
      <xs:documentation> The last_center_wavelength attribute provides
        the value at the center of the last bin along the spectral axis
        of a spectral data object in wavelength units.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:last_center_wavelength_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Length" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="last_center_wavenumber_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="last_center_wavenumber">
    <xs:annotation>
      <xs:documentation> The last_center_wavenumber attribute provides
        the value at the center of the last bin along the spectral axis
        of a spectral data object in wavenumber units.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:last_center_wavenumber_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Wavenumber" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="length_angle_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="length_angle">
    <xs:annotation>
      <xs:documentation> The length_angle attribute provides the angle
        subtended on the sky by the long dimension of a simple slit.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:length_angle_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Angle" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="net_integration_time_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="net_integration_time">
    <xs:annotation>
      <xs:documentation> The net_integration_time for a spectrum is the
        total integration time per pixel. For many detectors (CCDs, for
        example), all pixels are exposed simultaneously, so this value
        will correspond to the observation interval. In some cases,
        however, an instrument will sweep across pixels, rows, or
        planes, so that the observation period may be substantially
        longer than the actual integration time contributing to the
        individual pixels. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:net_integration_time_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Time" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="number_of_exposures">
    <xs:annotation>
      <xs:documentation> The number_of_exposures attribute indicates how
        many individual exposures or distinct integrations were combined
        to produce the spectrum. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Integer">
     <xs:minInclusive value="1"/>
     <xs:maxInclusive value="9223372036854775807"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="resolution_limit_energy_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="resolution_limit_energy">
    <xs:annotation>
      <xs:documentation> The resolution_limit_energy is the smallest
        possible distinguishable interval in energy for the instrument.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:resolution_limit_energy_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Energy" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="resolution_limit_frequency_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="resolution_limit_frequency">
    <xs:annotation>
      <xs:documentation> The resolution_limit_frequency is the smallest
        possible distinguishable interval in frequency for the
        instrument. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:resolution_limit_frequency_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Frequency" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="resolution_limit_wavelength_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="resolution_limit_wavelength">
    <xs:annotation>
      <xs:documentation> The resolution_limit_wavelength is the smallest
        possible distinguishable interval in wavelengths for the
        instrument. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:resolution_limit_wavelength_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Length" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="resolution_limit_wavenumber_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="resolution_limit_wavenumber">
    <xs:annotation>
      <xs:documentation> The resolution_limit_wavenumber is the smallest
        possible distinguishable interval in wavenumber for the
        instrument. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:resolution_limit_wavenumber_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Wavenumber" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="sampling_base">
    <xs:annotation>
      <xs:documentation> The sampling_base attribute indicates the
        numeric base of the associated logarithmic sampling interval.
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="sampling_interval_energy_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="sampling_interval_energy">
    <xs:annotation>
      <xs:documentation> The sampling_interval_energy attribute provides
        the spacing of points, in energy units, at which data are
        sampled and at which a value for an instrument or data parameter
        is available. This sampling interval can be either the original
        (raw) sampling or the result of some resampling process.
        </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:sampling_interval_energy_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Energy" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="sampling_interval_frequency_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="sampling_interval_frequency">
    <xs:annotation>
      <xs:documentation> The sampling_interval_frequency attribute
        provides the spacing of points, in frequency units, at which
        data are sampled and at which a value for an instrument or data
        parameter is available. This sampling interval can be either the
        original (raw) sampling or the result of some resampling
        process. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:sampling_interval_frequency_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Frequency" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="sampling_interval_wavelength_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="sampling_interval_wavelength">
    <xs:annotation>
      <xs:documentation> The sampling_interval_wavelength attribute
        provides the spacing of points, in wavelength units, at which
        data are sampled and at which a value for an instrument or data
        parameter is available. This sampling interval can be either the
        original (raw) sampling or the result of some resampling
        process. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:sampling_interval_wavelength_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Length" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="sampling_interval_wavenumber_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="sampling_interval_wavenumber">
    <xs:annotation>
      <xs:documentation> The sampling_interval_wavelength attribute
        provides the spacing of points, in wavenumber units, at which
        data are sampled and at which a value for an instrument or data
        parameter is available. This sampling interval can be either the
        original (raw) sampling or the result of some resampling
        process. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:sampling_interval_wavenumber_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Wavenumber" use="required" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>

  <xs:simpleType name="sampling_scale">
    <xs:annotation>
      <xs:documentation> The sampling_scale attribute indicates the type
        of scale that applies to the sample interval increments. It must
        have a value of either Linear or Logarithmic. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="solar_analog_star_name">
    <xs:annotation>
      <xs:documentation> The solar_analog_star_name attribute provides a
        name in a standard format (i.e., one that is recognized by the
        SIMBAD system) for the solar analog star used to reduce the raw
        spectral data to the reflectance units presented in this
        spectrum. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:UTF8_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="spectral_bin_type">
    <xs:annotation>
      <xs:documentation> The spectral_bin_type attribute contains one of
        a defined set of values that indicates the binned sampling
        parameter type (frequency, wavelength, or wavenumber) of the
        spectrum. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="spectrum_format">
    <xs:annotation>
      <xs:documentation> The spectrum_format attribute is required to
        define the specific dimensionality of the structure or
        substructure that contains the intensity values.
        </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="value_field_name">
    <xs:annotation>
      <xs:documentation> The value_field_name attribute is required for
        1D (linear) spectra. 1D spectra are presented as a table, where
        each row presents one point in the spectrum. This field must
        contain a string corresponding to the 'name' attribute of the
        table field that contains the spectral value. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="value_field_number_list">
    <xs:annotation>
      <xs:documentation> The value_field_number_list attribute is used
        only in the case spectra in the format "Tabulated-Flat", where
        each row of a table contains a spectrum and the spectral points
        are defined as individual Fields - one Field defined for each
        point. The format is a parenthesized, ordered list of the
        field_number values from the Field definitions that correspond
        to the spectral values. </xs:documentation>
    </xs:annotation>
    <xs:restriction base="pds:ASCII_Short_String_Collapsed">
    	<xs:pattern value='\(\s*[0-9]+(\s*,\s*[0-9]+)*\s*\)'/>
     <xs:minLength value="1"/>
     <xs:maxLength value="255"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:simpleType name="width_angle_WO_Units">
    <xs:restriction base="pds:ASCII_Real">
     <xs:minInclusive value="5.0e-324"/>
     <xs:maxInclusive value="1.7976931348623157e308"/>
	   </xs:restriction>
  </xs:simpleType>

  <xs:complexType name="width_angle">
    <xs:annotation>
      <xs:documentation> The width_angle is the angle subtended on the
        sky by the short dimension of a simple slit. </xs:documentation>
    </xs:annotation>
    <xs:simpleContent>
      <xs:extension base="sp:width_angle_WO_Units">
        <xs:attribute name="unit" type="pds:Units_of_Angle" use="required" />
        <xs:attribute name="nilReason" type="pds:nil_reason" use="optional" />
      </xs:extension>
    </xs:simpleContent>
  </xs:complexType>
</xs:schema>
