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, and ISO 19115-2 (in NASA specific MENDS and SMAP "flavors"). Click here to jump directly to the documentation.
Unified Metadata Model (UMM)
The 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), UMM-T (Tools) and UMM-Var (Variables).
For information regarding UMM-T, please refer to the CMR Documents page. Information on how to generate UMM-T records can be found in the MMT User's Guide.
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
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 the 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.
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 for collection-level metadata include:
UMM-JSON (UMM-C/Common)
DIF 10
ECHO 10
ISO 19115-2 MENDS
ISO 19115-2 SMAP
CMR supported metadata standards for granule-level metadata include:
UMM-JSON (UMM-G)
ECHO 10
ISO 19115-2 MENDS
ISO 19115-2 SMAP
Provided for each supported standard:
An element specification table that 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 versus the UMM. These differences are identified in the enumeration mapping table.
An example mapping showing how a snippet of metadata in the supported standard will appear in the UMM format. This may 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 to the newer version
History
Provides a version history for the metadata element
Documentation Directory
There is a separate wiki page for each high-level metadata concept in the UMM. Click on the expandable tables below to view a listing of available metadata concepts and access the documentation for each concept:
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.
This element and all of its sub-elements allow a data provider to provide archive and distribution file information upfront 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.
The direct distribution information main element allows data providers to provide users information on getting direct access to data products that are stored in the Amazon Web Service (AWS) S3 buckets when they are initially looking at a collection. The end users get information such as the S3 credentials end point, a credential documentation URL, as well as bucket prefix names, and an AWS region.
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.
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.
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)
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.
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).
This element defines how data may or may not be used to assure the protection of privacy or intellectual property. This includes license information as well as any special restrictions, legal prerequisites, terms and conditions, and/or limitations on using the dataset.
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.
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.
This 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.
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).
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.
This element describesapercentage value indicating how much of the area of a granule (the EOSDIS data unit) has been obscured by clouds. It is worth noting that there are many different measures of cloud cover within the EOSDIS data holdings and that the cloud cover parameter that is represented in the archive is dataset-specific.
This element describes the name of the geophysical parameter expressed in the data as well as associated quality flags and quality statistics. The quality statistics element contains measures of quality for the granule. The parameters used to set these measures are not preset and will be determined by the data producer. Each set of measures can occur many times either for the granule as a whole or for individual parameters. The quality flags contain the science, operational and automatic quality flags that indicate the overall quality assurance levels of specific parameter values within a granule.
Requires the user to add schema information into every granule record. It includes the schema's name, version, and URL location. The information is controlled through enumerations at the end of this schema.
This element describes the dates related to activities involving the granule and the data provider database with the exception of Delete. For Create, Update, and Insert, the date is the date that the granule file is created, updated, or inserted into the provider database by the provider. Delete is the date that the CMR should delete the granule metadata record from its repository.
Thiselementcontains attributes that describe the horizontal (geographical) and/or vertical region over which the data was acquired. Spatial Extent includes any or all of Granule Localities, Horizontal Spatial Domain, and Vertical Spatial Domain.
No
OR
Click here to see a list of all Collection level (UMM-C) metadata elements and corresponding documentation.
Click here to see list of all Granule level (UMM-G) metadata elements and corresponding documentation.
Additionally, there are some metadata concepts in CMR supported metadata standards that are not included in the UMM. Please refer to this wiki page for a list of ECHO 10 and DIF 10 metadata elements that do not translate to the UMM.
Additional Resources
Below are additional resources regarding the UMM and the CMR:
