About: http://webisa.webdatacommons.org/153654502

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	It is often difficult for a normally sighted person to judge when features, such as steps, are hard to see because of the complex interactions between lighting, the geometry of the feature, and its surface material.
http://www.w3.org/ns/prov#wasQuotedFrom	arvojournals.org