Data Dictionaries -

The following page links to version of the PDS4 Data Dictionaries, including XML Schema and Schematrons for the applicable PDS4 namespace.

Past versions of the data dictionaries can be found here.

Need help with creating a dictionary or where to start, please contact the PDS Operator at

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Data Dictionaries

Compatible Versions

For each version of the PDS Common Data Dictionary, there are specific discipline and mission dictionary that are compatible. You can find this information in our Dictionary Stacks database.

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PDS Common

PDS (pds)

This directory contains the XML Schema and Schematron files under the Planetary Data System (PDS) namespace. The JSON file contains an instance of the data dictionary in JavaScript Object Notation.

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Discipline Dictionaries

Cartography (cart)

The Cartography Dictionary contains classes, elements, attributes, and rules describing map projections, including both cartographic and lander related definitions and descriptions. The PDS Cartography dictionary is based on and with modifications and extensions applied by PDS as needed for planetary mapping application. utilizes the existing Federal Geographic Data Committee (FGDC) Content Standard for Digital Geospatial Metadata,

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Context Type List: Instrument (ctli)

The CTLI dictionary provides a set of type values for instruments for use in instrument context products.

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Display (disp)

The Display Dictionary contains classes, attributes, and rules for specifying how arrays (images) as stored, should be displayed to users. For example, defining the vertical display direction 'Bottom to Top' or horizontal direction 'Left to Right' and it can provide guidance on mapping multiband arrays for color display (red, green, and blue) or as a movie sequence (video).

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Surface Imaging (img_surface)

The Surface Imaging Dictionary contains classes, attributes, and rules for specifying the metadata associated with imaging and spectrometer data products of surface missions.

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Mission Information Commons (msn)

The sub-directory for the Mission Information class namespace.

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Surface Mission Information (msn_surface)

The Surface Mission Dictionary contains classes, attributes, and rules for specifying metadata elements which are specific to the data products of surface missions but are common among multiple such missions.

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MSSS Camera Mini-header (msss_cam_mh)

This dictionary is for a class of cameras developed by Malin Space Science Systems (MSSS) that share a common architecture or digital electronics assembly. Example cameras include Mastcam, MAHLI, MARDI, Mastcam-Z, SHERLOC-Watson and SHERLOC-ACI

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Multidimensional (multi)

The Multi dictionary contains classes that describe the composition of multidimensional data consisting of Array (and Array subclass) data objects. It provides a way to associated data objects and align the objects in general multi-dimensional structures.

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Nuclear Spectroscopy (nucspec)

The Nuclear Spectroscopy dictionary provides classes, attributes, and rules for describing the circumstances surrounding nuclear spectroscopy observations.

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Particle (particle)

The Particle dictionary contains attributes that may be used to help identify particle parameters included in a PDS4 product to supplement the information provided in the Primary_Result_Summary and in order to support enhanced data discovery.

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Processing_Information (proc)

The Processing_Information Dictionary contains detailed information regarding the history of processing performed on data product(s) in order to produce the current product.

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Spectral Library (speclib)

The Spectral Library Data Dictionary defines the metadata terms that describe laboratory spectral measurements, including classification of the samples measured.

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Spectral Discipline Dictionary (sp)

The Spectral (sp) Discipline Dictionary contains classes for defining the spectral bin characteristics (in wavelength, frequency, or wave number) of a data product.

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Survey (survey)

The Survey dictionary provides classes, attributes, and rules for describing the circumstances surrounding sky survey observations.

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Mission Dictionaries

All versions of the Mission data dictionaries can be found here.

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The PDS4 XML Schema and Schematron files are organized by namespace. For a list of existing namespaces, refer to the PDS Namespace Registry.

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How To Create A Dictionary

Please contact your applicable discipline node to ensure a new dictionary is necessary prior to beginning development. Once agreed upon, there are several places to go when trying to learn how to create a dictionary.

Once all information is gathered, create a ticket here to initialize a new PDS LDD and register it with the PDS Namespace Registry.

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Submitting A New Version

When a Local Data Dictionary (LDD) Steward is ready to submit a new version of an LDD for release:

Submit LDD Release Request

Note: Assume validation has been completed by steward.

Dictionary Validation

The LDD steward is encouraged to perform test/validation via one/both of the testing mechanisms:

Note: Currently, there is no explicit way to run validate to check out the schemas, but by reading the schemas into the tool, it will raise an error if they are invalid.

  • Open in Oxygen and click the red checkbox at the top.
  • Execute latest validate (version 1.16.0+) and specify the schemas via the command-line, for example:
    $ validate -x PDS4_CART_1C00_1932.xsd -S PDS4_CART_1C00_1932.xsd -t PDS4_CART_1C00_1932.xml

The PDS Engineering Node will also perform some basic testing and validation when a release is requested to ensure nothing makes it out as "released" that is invalid.

If there is an error, an email will be sent to the steward with error message(s).

If no error is found, the LDD will be posted to both latest and all schemas pages. An email will be sent to the steward indicating posting is completed.

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