Encoding Principles OGC Testbed-11 NIEM & IC Data Encoding Specification Assessment and Recommendations Engineering Report
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Copyright © 2016 Open Geospatial Consortium.
To support this flexibility, guiding principles were applied to the development of the NIEMIC Data Encoding. For example, it must support multiple namespaces and
complex nested schema. It must also be discoverable, self-describing and support interactive query and update. Finally, it must support multiple security tagged IEP
instance documents. The OGC Web Feature Service – Transactional WFS-T was selected as a template to test the NIEMIC Data Encoding since it supports all these
principles.
Using these principles and WFS-T as a template, the project assessed two ways of delivering the data encoding:
NIEM IEP containing ISM and NTK metadata as a member of wfs:FeatureCollection called the ‘NIEMIC WFS’
NIEM IEP with ISM and NTK metadata, appearing as the structured payload in a TDO, which in turn is a member of wfs:FeatureCollection. This encoding was
made available via the outputFormat parameter called ‘NIEMS’ This approach provided the NIEMIC WFS as a default option since it was assessed this
model may be more readily handled by server and client applications during initial testing. Three IEPs were converted, Notice of Arrival, Incident and Resource, into
NIEMIC wfs:FeatureCollection and tested during hands-on collaborative engineering. From that engineering a set of candidate rules were developed to guide the development
of NIEMIC Data Encoding in an environment where there may be hundreds of potential IEP instance documents, each with security tags. These rules are summarized in the
following sections.