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PDS 4 Data Design Report

PDS Management Council

April 2, 2009

PDS 2010 Data Design WG

Data Architecture Scope

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Key Deliverables• PDS4 Information Model

• The Information Model defines the objects in the PDS archive. This includes data structures, formats, and products as well as data sets, documents, missions.

• PDS4 Data Dictionary Model• The Data Dictionary Model provides the schema for the PDS data

dictionary. The data dictionary defines the data elements used in the PDS4 Information Model.

• PDS Standards Reference V4.0 and V4.1• Version 4.0 of the PDS Standards Reference document will be a rewrite

of Version 3.x. Version 4.1 will be an update released toward the end of the project.

• Grammar• The Grammar will be used to capture PDS archive metadata for

product labels. The plan is to replace or fix ODL. XML is being considered as an additional grammar.

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Data Design Working Group • Formed in December 2008• Personnel

• Steve Hughes (Lead)• Mitch Gordon (Rings)• Edward Guinness (Geosciences)• Lyle Huber (Atmospheres)• Ron Joyner (EN)• Anne Raugh (SBN)• Elizabeth Rye (Imaging, Standards)• Steve Joy (PPI)• Dick Simpson (Observer)

• Weekly Telecons• Project Website

• Just released version “m” of the model to the PDS engineering website.

• The design documents and example labels are re-generated after the application of updates to the information model database. 4

Data Design WG Schedule

• 04-Dec-2008 - Project and Project Members Defined • 31-Dec-2008 - Requirements updated• 30-Apr-2009 - General Data Model (Draft)• 30-Apr-2009 - Product Data Model (Draft)• 30-Apr-2009 - Data Dictionary Model (Draft)• 30-Apr-2009 - Grammar Options• 30-Apr-2009 - PDS Standards Reference (Outline)• 30-Sep-2009 - Data Dictionary Model (Final)• 30-Sep-2009 - Grammar Decision • 30-Sep-2009 - PDS Standards Reference (Draft)• Interim - PDS and community wide review• 30-Jul-2010 - General Data Model (Final)• 30-Jul-2010 - Product Data Model (Final)• 30-Jul-2010 - PDS Standards Reference (Final)

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Done

SubstantialProgress

PDS4 Data Product Concept Map

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Web View

Programmer View

Designer View

User View

Working Group Accomplishments To Date

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• Four basic data structures•Homogeneous N-dimensional array of scalars – Array_Base•Heterogeneous repeating record structure of scalars – Table_Base•Unencoded byte stream•Encoded byte stream

• Identifiable• Digital Product

• Data Product• 2-D Image

Product• …

• Document Set

• Non-Digital Product• Mission• Instrument• Resource

• Data Type• Binary Data Type

• Decimal Integer• …

• Character Literals• Character

Integer• …

• Array_Base• 2D_Array

• 2D_Image• 2D_Spectrum

• 3D-Array• 3D_Wavelength_Array

• 3D_Image• 3D-Spectral_Array

• 3D_Time_Array• Movie

• 3D_Spatial_Array• N>3-D Array

• Table_Base• Character_Table_Base• Binary_Table_Base

• Draft PDS Data Dictionary Model

• Grammar – ODL+, XML, and AnneML Labels

Prototype ODL+ Label Template (Data Structure)

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/* Object Section */ Object = 2D_Image axes_order = FAST2SLOW axis_length = (${axis_length}, ${axis_length}) axis_name = (${axis_name}, ${axis_name}) axis_type = (${axis_type}, ${axis_type}) axis_unit = (${axis_unit}, ${axis_unit}) byte_order = MSBF description = ${description} /* Optional */ element_bytes = ${element_bytes} /* Optional */ element_offset = ${element_offset} /* Optional */ element_scale = ${element_scale} /* Optional */ element_type = ${element_type} element_unit = ${element_unit} /* Optional */ first_element = TOPLEFT min_index = 0 number_of_axes = 2

End_Object = 2D_ImageEND

Prototype ODL+ Label Template(Other stuff)

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#PDS4#/* ******* Label Template : 2D_Image_Label ******* */ PDS_Unique_Identifier = ${PDS_Unique_Identifier}

/* Identification Section */ Object = Identification_Section dd_version_id = ${dd_version_id} label_revision_note = ${label_revision_note} pds_version_id = PDS4.0 End_Object = Identification_Section

/* Dataset Section */ Object = Dataset_Section data_set_id = ${data_set_id} End_Object = Dataset_Section

/* Instrument Section */ …/* Mission Section */ …/* Node Section */ …/* Circumstances of Observation Section */ …

Prototype XML Label – XML/Schema

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<?xml version="1.0" encoding="UTF-8"?><xs:schema xmlns:xs="http://www.w3.org/2001/XMLSchema">... <xs:complexType name="2D_Image_Type <xs:sequence> <xs:element name="axes_order" type="xs:string"> <xs:element name="axis_length" <xs:element name="axis_name" <xs:element name="axis_type" <xs:element name="axis_unit" <xs:element name="byte_order" <xs:element name="element_bytes" <xs:element name="element_offset" <xs:element name="element_scale" <xs:element name="element_type" <xs:element name="element_unit" <xs:element name="first_element" <xs:element name="min_index" <xs:element name="number_of_axes" </xs:sequence> </xs:complexType>

…

Prototype AnneML Label

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PDS4 Label { Use Dictionary PDS4; Use Dictionary <local data dictionary>;

… class 3D_Image { axes_order = FAST2SLOW; axis_length = (${axis_length},${axis_length}, $

{axis_length}); axis_name = (${axis_name}, ${axis_name}, ${axis_name}); axis_type = (${axis_type}, ${axis_type}, ${axis_type}); axis_unit = (${axis_unit}, ${axis_unit}, ${axis_unit}); … element_bytes = ${element_bytes}; /* Optional */ element_offset = ${element_offset}; /* Optional */ element_scale = ${element_scale}; /* Optional */ element_type = ${element_type}; element_unit = ${element_unit}; /* Optional */… number_of_axes = 3; …};

Next Steps

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• Continue design work in preparation for Tech Session

• PDS Technical Staff Review

• Information Model• Obtain consent to continue along current design path

• Grammar • Present options and move toward adoption of one or two of

the options

• Data Dictionary Model• Present draft model and consider adoption

• Standards Reference• Present outline and request feedback