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The National Map

Home ← Geospatial Semantics and Ontology

Geospatial Semantics and Ontology

The goal of the project "Building Ontology for The National Map" is to specify geospatial feature semantics for the Resource Description Framework (RDF) data model with the objective to translate traditional topographic information into a flexible spatiotemporal knowledge base to serve many different application areas.

Constructing Ontologies from The National Map Triples

Guide for Creating and Using National Map RDF Data

This procedure converts data for the hydrography, transportation, and government units themes of The National Map. The original form of these datasets is in Esri GDB (Geographic Data Base format) and the goal is to convert it to XML / JSON. The procedure consists of three basic steps: Step 1: Retrieving data from Amazon S3 , Step 2: Converting the retrieved GDB files to XML, Step 3: Converting XML files to required format (mostly JSON). The detailed description of each step is described in the linked document. Data downloaded from the Geographic Names Information System (GNIS) can be converted into RDF triples by using this program. More information about the GNIS to RDF Conversion Program can be found here Geographic Names Information System (GNIS).

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

Ecological Regimes

Surface Water


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.

More Information

Papers and Posters

A collection of publications, posters, and reports are available for specific information about geospatial semantics and ontology.

Abstracts, Presentations and Activities

Our involvement in related events, presentations, and abstracts are included here.

Virtual Communities

Project Team

Dalia Varanka, Project Lead

E. Lynn Usery

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Last modified: Friday, 04-Aug-2017 13:43:31 EDT