<http://webisa.webdatacommons.org/271436212> <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/prov#Entity> . <http://webisa.webdatacommons.org/prov/195412388> <http://www.w3.org/ns/prov#wasDerivedFrom> <http://webisa.webdatacommons.org/271436212> . <http://webisa.webdatacommons.org/271436212> <http://www.w3.org/ns/prov#value> "Obstacles and areas such as lava beds or salt marshes," . <http://webisa.webdatacommons.org/271436212> <http://www.w3.org/ns/prov#wasQuotedFrom> <cavalrypilot.com> .