ISO Scope Codes
The metadata universe has traditionally been classified into bins for collection level, catalog level, and granule level metadata (or some other similar classification scheme). It is not unusual for each of these levels to require a different approach to metadata and tool development. Many systems have been developed that are focused on a single "level" of documentation.
The ISO 19115 standard changes this picture by including a ScopeCode in each metadata record. This code describes what the metadata actually applies to and it can have many values: attribute, attributeType, collectionHardware, collectionSession, dataset, series, nonGeographicDataset, dimensionGroup, feature, featureType, propertyType, fieldSession, software, service, model, and tile (see Figure). In fact, it has recently been proposed that this list be expanded considerably.
The name of the scopeCode, hierarchyLevel, implies an hierarchical structure for the metadata. this may not be appropriate in all cases and, in fact, may be confusing. It is probably beneficial to think more in terms of a traditional scope concept than a hierarchy level in this case.
The Scope Code can be used at three different locations in the ISO standard: in the metadata record itself, as shown here, or in a data quality or maintenance report. For example, this allows a quality report about specific attributes or features or for particular collection hardware, for example.
We may need to rethink some of our traditional divisions as we learn to use this powerful new capability in ISO.
The ScopeCode in the MD/MI_Metadata describes what the entire metadata record applies to. The default value for this code is "dataset". How might other values be used?
- dimensionGroup: This code can be used in Forecast Model Run Collections to identify a group of layers that share the same dimensions.
- series: The ISO Standard includes the capability to describe dataset aggregates or series. In this case the seriesMetadata would have hierarchyLevel="series".
- service: The ISO 19119 Standard that describes services shares the MD/MI_Metadata object with 19115. Service metadata includes information about the service and references to the datasets it serves. If the primary purpose of the metadata record is to describe the service, it makes sense for the hierarchyLevel to be "service".
The ISO 19139 Technical Specification included some significant extensions to this code list. The extended code list is MX_ScopeCode and it includes initiative, stereomate, sensor, platformSeries, sensorSeries, productionSeries, transferAggregate, otherAggregate.
<gmd:hierarchyLevel> <gmd:MD_ScopeCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ScopeCode" codeListValue="dataset">dataset</gmd:MD_ScopeCode> </gmd:hierarchyLevel> or <gmd:hierarchyLevel> <gmd:MD_ScopeCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ScopeCode" codeListValue="series">series</gmd:MD_ScopeCode> </gmd:hierarchyLevel> or <gmd:hierarchyLevel> <gmd:MD_ScopeCode codeList="http://www.isotc211.org/2005/resources/Codelist/gmxCodelists.xml#MD_ScopeCode" codeListValue="service">service</gmd:MD_ScopeCode> </gmd:hierarchyLevel>