A prototype system for managing, querying, and retrieving data from The National Map in Resource Description Framework (RDF) is unofficially released at https://code.usgs.gov/makb/. The objective of the system is to integrate cross-thematic geographic information system features from The National Map and to coreference data from various sources and formats.
The Map as Knowledge Base project is developing a prototype system for delivering data from The National Map as Linked Open Data (LOD). The user interface of this system engages various visualization methods for users to quary, evaluate, and retrieve data from the USGS and non-USGS sources. The core concept is that data would be co-referenced, displayed and available for further exploration. The UI supports the browseable graph approach for data queries that more specifically allows the user to limit data to their criteria and integrate with related data.
The general logical diagram of the system to execute the concept described aboce is shown below the high-level diagram in the workflow diagram. The system modules are all free and open-source software.
Several starting points are possible for the Map as Knowledge Base user. SPARQL or GeoSPARQL queries are assisted with a query builder. The image shown below assists the selection of a graph dataset, selection of properties, and filtering results, among other semi-automated functions.
The user interface lists datasets to select through a menu.
When selcting a feature of interest, a pop-up window apears with property links, as shown in the image below. An option to query more information returns additional properties.
In addition to map visualization an ontology can be viewed either as a separate window for full viewing, or a smaller inset view for focused on a feature of interest.
Converting Data from The National Map to Resource Description Framework (RDF)
This procedure converts data for the vector format themes of The National Map (Transportation, Government Boundaries,Structures, and Hydrography). These datasets typically take the form of Esri GDB (Geographic Data Base format). The goal is to convert them 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 / JSON-LD).
The files are compressed and can be download here TOPO Files.zip or from the tab below.