ISO Distribution Information
The ISO MD_Distribution Object provides information about where users can get data, the formats available, and the processes for ordering the data. Distribution Organization. The MD_Distribution object includes any number of distributors, distributionFormats, and transfer options. This flexibility is good, but the many-to-many relationships between these objects can make it difficult to unambiguously specify distribution information. Three approaches to organizing this information are shown in the Figure to the right.
The first approach (left column in Figure) works well in situations wherer the data are available in a single format from a single distributor. In that case the distributor, distributionFormat, and transferOptions roles can be used directly from the MD_Distribution object.
In more complex situations where the data are available from multiple distributors (center column in Figure), a MD_Distributor object must exist for each distributor and each would have associated distributorFormats and distributorTransferOptions. This approach actually requires a separate MD_Distributor for each unique combination of distributorFormat and distributorTransferOptions in order to unambiguously associate the correct transferOption with each distributionFormat.
The final approach (right column in Figure) is becoming available in the revision of 19115 (19115-1). This revision adds a distributionFormat role to the MD_DigitalTransferOptions object which allows a single MD_Distributor to unambiguously describe multiple transferOptions each of which has an associated format.