EHG6207 - Aerial photographic survey - Knock Farril

An aerial photographic survey was carried out by Skyscape Survey in 2021 of the Knock Farril hillfort near Dingwall. The survey was carried out using a camera mounted on a SUA (drone) in order to capture images for processing into a detailed contour plan of the site at 20cm interval, allowing for 3D modelling and survey interpretation. In addition, images were taken of the site from a variety of angles, placing it into the landscape. The area covered by the survey included the site and up to 60m from the outer ramparts to all directions. Using over 895 oblique images across the site, a high resolution 3D model of the site was created using Agisoft Photoscan – the resulting Data Surface Model (DSM) was processed to remove vegetation, to leave a Data Terrain Model (DTM). The resulting high resolution model was transformed into a referenced GeoTIFF Digital Elevation Model (DEM) used as the base for a 5cm interval contour model in CAD and as GIS shp files. In addition, a georeferenced ortho-image of the site was produced and 3d model viewable on html browser. A new enclosure was located within the main site bounds, attached to the later rectangular structure, while a possible track was observed on the south side of the ridge rising up to the bank located at the southwest end of the site. The possible earlier bank wall was also traced along the south side, beneath the vitrified rampart. <1>