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 Other and NASA collections to understand how does this choice effects the metadata content.

Data Selection

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

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Note:

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Five elements exist in all NASA 2017 Collections and in a smaller number of NASA 2016 collections. See the All 2017 and Some 2016 filtered view to identify these elements.

Elements in No NASA 2017 Collections and some NASA 2016 Collections

Twenty-one elements exist in some NASA 2016 Collections and in no NASA 2017 collections. See the Some 2016 and None 2017 filtered view to identify these elements.

Elements in No NASA 2016 Collections and some NASA 2017 Collections

Forty-eight elements exist in some NASA 2017 Collections and in no NASA 2016 collections. See the Some 2017 and None 2016 filtered view to identify these elements.