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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 originate in DIF format. These are referred to here as the SciOps collectiongroup. The second largest portion of metadata for NASA collections originate come from ECHO and are inserted into the CMR the NASA DAACs and originate in ECHO format. These are referred to here as the NASA collectiongroup. 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 that participate in the International Directory Network. These records originate in DIF  and are referred to as the Other collectionIDN group.

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

Data Selection

The SciOps data collection includes over 13,000 metadata records from nearly 2,000 different sources, most outside of NASA. Over 1700 of these sources have less than ten metadata records. Assuming that there is variation in metadata creation techniques for these providers, this is likely not a homogeneous collection. We identified 25 providers that have collections with one hundred or more records and examined those as separate collections. Table 1 below shows the 18 NASA provider and 25 SciOps Providers considered in this evaluation, as well as the record count for each provider.

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