Gleaner is the structured data on the web indexing tool developed as part of the NSF EarthCube Project 418. Gleaner's focus is on collection JSON-LD encoding data graphs about data resources and services. Gleaner can then process and generate a semantic network based on a list of providers. These semantic networks can then be used to build services or connected with other networks.
A detailed screencast on using Gleaner to build a semantic network.