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Overview

The CMR includes metadata that originate in three dialects: DIF, ECHO, and ISO. The largest portion of CMR collection records are in the SciOps collection, and are inserted into the CMR in DIF format. These are referred to here as the SciOps collection. The second largest portion of metadata for NASA collections originate from ECHO and are inserted into the CMR in ECHO format. These are referred to here as the NASA collection. A third group of metadata in the CMR originate from other agencies around the world and are generally either in DIF or possibly in ISO. These are referred to as the Other collection.

The DIF and ECHO dialects were originally developed to facilitate discovery of collections in the Global Change Master Directory or ECHO. The content of these “discovery” dialects is translated into the ISO dialects that are the eventual target for CMR. This translation is generally done without augmentation, so the content does not change very much.

Metadata providers have a choice about which metadata dialect(s) they use to submit metadata to the CMR. We compared the IDN and NASA collections to understand how this choice affects the metadata content.

Data Selection

The table below shows the collection included in this evaluation as well as the record count for each collection.

Table 1. Collections and record counts

IDN vs. NASA

This analysis compares item usage (elements and attributes) in the 18 NASA collection with the 8 non NASA (IDN) collections.  This evaluation identifies items which exist in collections as well as items that are complete in collections.  In order for an items to exist in a collection it must be present in at least 1 metadata record included in the collection. In order for an items to be complete in a collection it must be present in all metadata records included in the collection. 

Item usage for NASA collections and IDN collections is shown below using bubble charts.  The bubble chart interpretation graphic provides a schematic for interpreting the bubble plots. 

Bubble Chart Interpretation

Not Provided Values

The CMR team are in the difficult position of trying to make a coherent and useful metadata repository by collecting metadata from many organizations and projects that have different goals and needs.  This presents a challenge as the CMR evolves and new requirements emerge. Metadata managers need to account for content that is not provided by the metadata providers. At the current time, this is between three and five percent of the content.

The solution for both NASA, IDN, and SciOps provided collections and IDN provided collections is to add the string “Not provided” to expected fields that have no content. This clearly indicates that content is missing, except that tools that read the metadata or translate it must be aware of and consider this convention to get meaningful results. The tools we use for evaluating metadata completeness are agnostic to element and attribute values.  Therefore the analysis presented below, which compares NASA Complete with IDN Complete does not include metadata fields with a value of 'Not Provided'.  Below are the metadata fields with 'Not Provided' values that were excluded from NASA Complete vs IDN Complete evaluation

NASA Collections - Fields with ‘Not Provided values'

/gmi:acquisitionInformation/gmi:instrument/gmi:type

/gmd:identificationInfo/gmd:pointOfContact/gmd:organisationName

/gmd:identificationInfo/gmd:abstract

/gmd:identificationInfo/gmd:descriptiveKeywords/gmd:keyword

/gmd:identificationInfo/gmd:resourceConstraints/gmd:useLimitation

/gmd:contentInfo/gmd:processingLevelCode/gmd:code

/gmd:identificationInfo/gmd:pointOfContact/gmd:individualName

/gmi:acquisitionInformation/gmi:instrument/eos:sensor/eos:type

/gmd:contact/gmd:organisationName

/gmi:acquisitionInformation/gmi:platform/gmi:identifier/gmd:code

/gmd:contentInfo/gmd:dimension/gmd:otherProperty/gco:Record/eos:AdditionalAttributes/eos:AdditionalAttribute/eos:reference/eos:description

/gmd:identificationInfo/gmd:processingLevel/gmd:code

/gmi:acquisitionInformation/gmi:platform/gmi:description

/gmd:identificationInfo/gmd:status/gmd:MD_ProgressCode

IDN Collections - Fields with ‘Not Provided values'

/gmd:identificationInfo/gmd:processingLevel/gmd:code

/gmd:identificationInfo/gmd:status/@codeListValue

/gmd:identificationInfo/gmd:citation/gmd:edition

/gmi:acquisitionInformation/gmi:platform/gmi:description

/gmd:identificationInfo/gmd:descriptiveKeywords/gmd:keyword

/gmd:contentInfo/gmd:dimension/gmd:otherProperty/gco:Record/eos:AdditionalAttributes/eos:AdditionalAttribute/eos:reference/eos:description

/gmi:acquisitionInformation/gmi:instrument/gmi:type

/gmi:acquisitionInformation/gmi:platform/gmi:identifier/gmd:code

/gmd:identificationInfo/gmd:status/gmd:MD_ProgressCode

/gmd:identificationInfo/gmd:abstract

/gmd:contentInfo/gmd:processingLevelCode/gmd:code

/gmd:identificationInfo/gmd:citation/gmd:identifier/gmd:version

NASA Complete vs IDN Complete

Chart 1 below compares item completeness in NASA Collections with IDN collections.  The X axis shows the number of NASA collections that are complete with respect to an item. The Y axis shows number of IDN collections that are complete with respect to an element  The bubble size shows the number of items included in the 2 collections.

The large red bubble in the upper right corner of the plot shows items (elements and attributes) that are complete is all 18 NASA collections and in all 8 IDN collections.  This bubble includes 27 items, as shown in the legend.  The large blue bubble in the lower left corner of the plot shows the items that are complete in 1 NASA collection and in 0 IDN collections.  This bubble includes 38 items, as shown in the legend. Click on the image to view the data for this chart.

Chart 1: NASA Complete vs IDN Complete

Accessing the Chart

To access the data for this chart, click on the chart graphic above to view an interactive version in Google Sheets.  The interactive version enables data identification for each bubble and includes a look up table for identifying the ISO elements associated with the bubble. To access and use the interactive version:

1. Click on the chart graphic above to view the chart in Google Sheets
2. Hover over the bubbles with your mouse to identify the number of complete NASA collections and the number of complete IDN collections associated with the bubble.  The hover identification also shows the number of element (Counts) associated with each bubble.
3. To the right of the chart is a lookup table for identifying the xpaths associated with each of the bubbles.  To identify the xpaths associated with a bubble, match the NASA Provided Complete and IDN Provided Complete values from the bubble hover with the values in the look up table.

Elements complete in all NASA and IDN Collections

Twenty-seven items (elements and attributes) are complete in all NASA and all IDN Collections:  See the All NASA and All IDN filtered view to identify these items.

Elements complete in all NASA Collections and some IDN Collections

Only one element is complete in all NASA collections and some IDN collections: gmd:identificationInfo/gmd:citation/gmd:edition. This reflects the fact that this element is used in the NASA collections to provide version information for resources.

Elements complete in all IDN Collections and some NASA Collections  

Nineteen items (elements and attributes) are complete in all IDN collections and complete in a smaller number of NASA collections. These are the bubbles along the top of the chart. See the All IDN and Some NASA Complete filtered view to identify these items.

Elements complete in no IDN Collections and some NASA Collections

Sixty-three elements are complete in no IDN Collections and some NASA Collections. These are the bubbles on the X axis in the chart. None are complete in more than nine NASA collections. Many of these elements are related to keyword thesaurus and additional attribute information. It is interesting to note that keyword thesaurus information is completely absent from the IDN collections, reflecting the fact that GCMD keywords are used in those collections, perhaps as a requirement of participation in the IDN. 

NASA Exists vs IDN Exists

Chart 2 below compares item existence (elements and attributes) in NASA Collections with IDN collections.  The X axis shows the number of NASA collections that include an item. The Y axis shows number of IDN collections that include an item.  The bubble size shows the number of items included in the 2 collections.

The large blue bubble in the upper right corner of the plot shows the items (elements and attributes) that exist is all 18 NASA collections and in all 8 IDN collections.  This bubble includes 51 items, as shown in the legend.  The large red bubble in the lower left corner of the plot shows items that exist is one NASA collection and in zero IDN collections.  This bubble includes 44 items, as shown in the legend. The data for Chart 2 is accessible in Google Sheets.  To view the data and bubble chart in Google Sheets click on the image. 

Chart 2: NASA EXIST vs IDN Exists

Accessing the Chart

To access the data for this chart, click on the chart graphic above to view an interactive version in Google Sheets.  The interactive version enables data identification for each bubble and includes a look up table for identifying the ISO items associated with the bubble. To access and use the interactive version:

1. Click on the chart graphic above to view the chart in Google Sheets
2. Hover over the bubbles with your mouse to identify the concept existence in NASA collections and concept existence in IDN collections associated with the bubble.  The hover identification also shows the number of items (Counts) associated with each bubble.
3. To the right of the chart is a lookup table for identifying the xpaths associated with each of the bubbles.  To identify the xpaths associated with a bubble, match the NASA Exists and IDN Exists values from the bubble hover with the values in the look up table.

Elements in all Other Collections and some NASA Collections

Fifty-two elements exist in all IDN Collections and some NASA collections. These are the bubbles along the top of the chart. See All IDN - Some NASA Exists for the list.

Elements in some NASA Collections and no IDN Collections

One hundred and fifteen items (elements and attributes) are complete in zero IDN collections and are complete some number of NASA collections. See the No IDN and Some NASA filtered view to identify these items.

Other Filters

• View just Elements
• View just Attributes