With respect to historical studies, a primary source is a record that was created at the time the event being described or otherwise recorded took place, or a record that was created shortly afterwards by someone who personally witnessed or participated in the event. For the purposes of the SCRCA Project, potentially useful / interesting historical primary source material is likely to include maps, land-plans, distance diagrams, construction drawings, engineer’s drawings, structural plans, Historic Environment Records, county, parish & census records, archaeological survey reports, photographs, film / video footage (including driver's eye view footage), aerial imagery (including LiDAR imagery and infra-red / visible spectrum photography), news reports, oral histories, physical artefacts in museums & private collections and, of course, physical structures such as historic buildings and bridges that still stand in the landscape. Modern-day primary sources include photographs taken and notes made during assessment visits carried out by SCRCA Project volunteers. For the purposes of the SCRCA Project, the terms primary sources and primary source material are effectively synonyms, although the latter tends to be used when the emphasis of a sentence needs to be placed on the physical material itself (e.g. the maps, photographs, etc) rather than the information contained in or conveyed by that material. See also Primary source material and contemporary accounts relating to the construction of the Settle-Carlisle Railway and secondary source.