Guide for Creating and Using National Map RDF Data
Data downloaded from the Geographic Names Information System (GNIS) can be converted into RDF triples by using this program.
Notes on generating National Map data into RDF
“Personal GDB 9.2” format is required to generate National Map data into RDF. The Viewer does not offer “Personal GDB 9.2” format but this format can be generated from the “GDB 9.3” and “GDB 10.0”, formats the Viewer does offer, by using FME Desktop, the spatial Extract, Transform, Load (ETL) tool.
More information about the GNIS to RDF Conversion Program can be found on the Geographic Names Information System (GNIS) FAQ
USGS Created Ontologies
- GIS NHD is a simple ontology directly converted using the program linked from “Guide for Creating and Using National Map RDF Data.” NHD attribute headings take the form of object and datatype properties. Table names serve as domain and range classes for properties.
- This surface water ontology (SWO) is based on GIS NHD, but organized using the Basic Formal Ontology (BFO) and modified for semantic technology conventions.
- USTopographic is a simple ontology formed to connect separate semantic modules for The National Map.
The Topographic Feature Vocabularies
A controlled vocabulary provides a way to specify triple data semantics. Formal specifications provide a cohesive basis for a topographic feature type vocabulary for triple data. The feature list is based on standards for the various themes of The National Map, the Digital Line Graph (DLG) feature list derived from field-surveyed 20th-century maps, the Geographic Names Information System (GNIS), and the Spatial Data Transfer Standard (SDTS).
(The files are in Terse RDF Triple Language (Turtle), which uses the file extension .ttl. )
Built Up Areas
The vocabulary is not meant to be a comprehensive inventory of all available scientific terms. The terms were selected for the original standards based on whether the USGS would produce digital data for those feature types or whether they are recognized in other data sets. The feature list vocabularies will continue to be reviewed and updated.
SPARQL Endpoint and Sample Data
Selected data sets from The National Map are now available in the data model of the Semantic Web, Resource Description Framework (RDF) triples. These triples can be downloaded and used as linked data for Web 2.0 and Web 3.0 applications. A SPARQL endpoint is available for querying and saving subsets of the data.
E. Lynn Usery