4. Data Content and Structure

G-NAF is a feature-based product. A data model is included (Appendix B) with an associated data dictionary (Appendix C).

4.1. Feature-based data

Data types and codes are derived from the address standard where applicable. However, in some cases, the codes have been extended to handle exceptional cases. The data model is hierarchical, storing information about streets and localities separate from address sites. Alias addresses are stored in the same way as principal addresses. There is simply a ‘mapping’ table provided to determine which address is an alias of which principal address.

4.2. Feature-based application schema (data model)

The G-NAF data model is set out in Appendix B.

4.3. Data dictionary

The G-NAF feature catalogue in support of the application schema is provided in Appendix C. Spatial attributes are added to the feature catalogue in the same manner as other attributes for completeness and conformance to the application schema.

4.4. Feature-based content scope

All geometry and metadata for points within G-NAF.