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DRAFT

Introduction

This wiki resource provides best practices documentation for all collection and granule metadata concepts supported by the Common Metadata Repository (CMR). It is intended to support metadata authors as well as provide general guidance to those seeking information about CMR supported metadata. 

The wiki is organized by metadata concept as specified in the Unified Metadata Model (UMM) and includes information such as: required metadata fields, definitions for each metadata concept, best practices for populating each metadata field, guidance on how to use controlled vocabularies, and the revision history of the UMM metadata schema. Also included are a detailed mapping/crosswalk between each UMM metadata field and the corresponding field in each CMR supported metadata standard. Supported standards currently include ECHO 10, DIF 10, ISO 19115-2 (in NASA specific MENDS and SMAP "flavors"), and ISO 19115-1. Click here to jump directly to the documentation.  

Unified Metadata Model (UMM)

The Unified Metadata Model (UMM) is used as a bridge to map between each of the CMR-supported metadata standards. A number of different objects require descriptive metadata that is modeled using a corresponding UMM profile. For example, a collection (or dataset level) object is modeled using the UMM-C (Collection) profile, and granule (or file level) objects are modeled using the UMM-G (Granule) profile.

While UMM-C and UMM-G are separate entities, some elements are common to each profile and are therefore modeled using UMM-Common.

Currently, this wiki resource provides documentation for elements found in the UMM-C, UMM-G and UMM-Common models. 

Other UMM models not covered here include UMM-S (Services) and UMM-Var (Variables). 

For information regarding UMM-S please refer to the CMR Documents page and the UMM-S Curator's Guide.

For information regarding UMM-Var please download the UMM-Var document from the CMR Documents page.  

Wiki Page Structure

Each wiki page is structured as follows:


Element Description

  • Provides a high level definition of the metadata concept

Best Practices

  • Provides best practices for the metadata concept as well as example values

Element Specification

  • A table detailing each unique metadata element within the concept. For each metadata element the table specifies:
    • The UMM model it is from (UMM-Common, C or G)
    • The element name, exactly as it appears in the UMM schema
    • The element type (string, decimal, enumeration, boolean, etc.)
    • Constraints (e.g. character length restrictions, controlled vocabularies, etc.)
    • The cardinality, which specifies how many times the element may be repeated. See the following for a more in depth explanation of cardinality: <insert link> 
    • Notes: any additional information which may be useful about the element

Metadata Validation and QA/QC

  • There are various systems in place to ensure a certain standard of metadata quality is maintained in the CMR. The Metadata Validation and QA/QC section of the wiki page provides documentation regarding these efforts and systems:
    • GCMD Metadata QA/QC: The GCMD team is responsible for stewardship of metadata records in the CMR provided by any of CMR's International Directory Network (IDN) partners. This section details both the automated and manual checks the GCMD team performs on the IDN records to help maintain a certain standard of quality.
    • CMR Validation: The CMR system itself has certain requirements. This section details any baseline CMR requirements for the metadata concept in question.
    • ARC Metadata QA/QC: The ARC team is responsible for performing quality assessments of NASA metadata records in the CMR. This section specifies what the ARC team looks for (both manually and in an automated fashion) to ensure NASA's metadata records in the CMR maintain a certain standard of quality. 

   Dialect Mappings

  • The Dialect Mapping section provides detailed element-element mappings between the UMM and each CMR supported metadata standard. Current CMR supported metadata standards include:
    • DIF 10 
    • ECHO 10
    • ISO 19115-2 MENDS
    • ISO 19115-2 SMAP
  • Provided for each supported standard:
    • An element specification table which includes the direct crosswalk between the UMM element path and the corresponding element path in the supported standard. This table will also indicate if an element in a supported standard does not map to the UMM, or if there are any caveats in the manner that the information gets translated.
    • An enumeration mapping table (if applicable) - sometimes there are differences in enumeration values used in a supported standard VS the UMM.
    • An example mapping showing how a snippet of metadata in the supported standard will appear in the UMM format. This might illustrate examples of how certain information can get dropped or only partially translated between the supported standard and the UMM.  

UMM Migration

  • If a metadata concept undergoes significant changes between UMM version updates, this section will illustrate how the information provided in the older UMM version gets translated over to the newer version.

Future Mapping

  • Note: this section of the wiki will be hidden from the public soon.

History

  • Provides a version history for the metadata element in question

Documentation Directory

There is a separate wiki page for each high level metadata concept in the UMM. The tables below link directly to the documentation for each concept:


ElementUMM ModelDefinitionRequired
Abstract
This element provides a brief description of the dataset the metadata represents.Yes
Access Constraints
This element describes any restrictions imposed on data access. Access Constraints can be described in a free text field with the option to provide an access control list (ACL) value. No
Archive and Distribution Information
This element and all of its sub elements allow a data provider to provide archive and distribution file information up front to an end user, to help them decide if they can use the product. The file information includes AverageFileSize - typically used for granules as well as file formats and other file information.No
Collection Citation
This element provides the information required to properly cite the collection in professional scientific literature.No
Collection Data Type
This element is used to identify the collection as a Science Quality Collection or as a non-science-quality collection such as a Near Real Time collection.No
Collection Progress
This element describes the production status of the dataset.Yes
Contact Group
This element is used to provide contact information for a group associated with the dataset. No
Contact Person
This element is used to provide contact information for an individual associated with the dataset.No

Data Center


This element is used to identify and provide contact information for the organization responsible for originating, processing, archiving, and/or distributing the dataset being described in the metadata.  Yes
Data Dates
This element is used to identify dates when the data or resource itself changed in some way. No
Data Language
This element describes the language used in the preparation, storage, and description of the collection. It is the language of the collection data itself. It does not refer to the language used in the metadata record (although this may be the same language)No
DOI
This element stores the DOI (Digital Object Identifier) that identifies the dataset.Yes, if applicable
Entry Title
This element describes the title of the dataset described by the metadata.


Yes
Maturity

This element describes the collection life cycle. There are four valid values: Beta refers to collections that intend to enable users to gain familiarity with the collections parameters and data formats. Provisional collections allow users to find the data and process studies where the product doesn't need rigorous validation or top quality. Validated products are high quality data that have been fully validated. Deprecated products have been retired but are still discoverable for historical purposes.

No
Metadata Association
This element is used to identify other metadata resources that are dependent on or related to the data described by the metadata.No
Processing Level
This element describes an identifier indicating the level at which the data in the collection are processed, ranging from level 0 (raw instrument data at full resolution) to level 4 (model output or analysis results). Yes
Publication Reference
This element describes key bibliographic citations pertaining to the collection.No
Purpose
This element contains suggested usage for the data and/or a description for why the resource exists.No

Quality


This element describes the quality of the dataset.

No
Short Name
This element describes the dataset short name.Yes
Use Constraints
This element defines how data may or may not be used to assure the protection of privacy or intellectual property. This includes license information, or any special restrictions, legal prerequisites, terms and conditions, and/or limitations on using the dataset.No
Version
This element describes the dataset version.Yes
Version Description
This element describes the version of the dataset.No
ElementUMM ModelDefinitionRequired?
Temporal Extent
This element describes when data were acquired or collected.No
Temporal Keywords
This element specifies a word or phrase which serves to summarize the temporal characteristics of a dataset.No
Paleo Temporal Coverage
This element defines the time period for geologic and/or paleoclimate data. The element is predominantly used for data samples that originated prior to 01-01-0001. No
ElementUMM ModelDefinitionRequired?
Spatial ExtentUMM-CommonThis element describes the geographic coverage of the data.Yes
Spatial Information
This element stores information about the reference frame from which horizontal and vertical spatial domains are measured. The horizontal reference frame includes fields for Geodetic Model, Geographic Coordinates, and Local Coordinates. The Vertical reference frame includes fields for altitudes (elevations) and depths.No
Tiling Identification System
This element defines a named two-dimensional tiling system related to the collection. No
Location KeywordsUMM-CThis element contains keywords that characterize the study area/region where data was collected.No
ElementUMM ModelDefinitionRequired?
PlatformUMM-CommonThis element describes the relevant platforms used to acquire the data.Yes
InstrumentUMM-CommonThis element is used to register the device that measured or recorded the data, including direct human observation.Yes
ProjectUMM-CommonThis element describes the scientific endeavor(s) with which the collection is associated.No
ElementUMM ModelDefinitionRequired?

Related URL

UMM-CommonThis element describes any resource-related URLs that include project home pages, resource information pages, services, related data, archives/servers, metadata extensions, direct links to online software packages, web mapping services, links to images, documents, or other data.Yes
Online Resource
  • no wiki page for this concept

ElementUMM ModelDefinitionRequired?
Science Keywords
This element enables specification of Earth Science keywords.Yes
Ancillary Keywords
This element allows metadata authors to provide words or phrases beyond the controlled Science Keyword vocabulary, to further describe the the collection.No
ISO Topic Category
This element identifies the topic category (or categories) from the EN ISO 19115 Topic Category Code List that pertain to a collection.No
Additional Attributes
This element stores the data's distinctive attributes (i.e. attributes used to describe the unique characteristics of the resource which extend beyond those defined in this mapping).No
ElementUMM ModelDefinitionRequired?
Metadata Language
This element specifies the language used in the metadata record (i.e. English, French, Chinese, etc.).No
Metadata Dates
This element is used to identify dates when the metadata changed in some way. This element is made of two sub-elements, Type and Date.No
Directory Names
This element has been used historically by the GCMD internally to identify association, responsibility and/or ownership of the dataset, service or supplemental information. Note: This field only occurs in the DIF. When a DIF record is retrieved in the ECHO10 or ISO 19115 formats, this element will not be translated.No


Additional Resources

Below are additional resources regarding the UMM and the CMR:

Unified Metadata Model:

Miscellaneous CMR Resources








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