Positional Accuracy Assessment of Digital Orthophoto Based on UAV Images: An Experience on an Archaeological Area

Abstract

Rapid development in UAV (unmanned aerial vehicle) photogrammetry made it preferable in many applications including cultural heritage documentation. Usability, quickness and accuracy of digital images have grabbed also the attention of archaeologists. Especially orthoimages by UAVs have become considerably significant in the field of archaeological heritage documentation since they are fast and accurate images of the object with high detailed information. However their accuracy and quality are the most important features of these images for archaeological documentation. The aim of this paper is to evaluate horizontal and vertical accuracy of an orthophoto taken by a fixed-wing UAV in an archaeological area. The evaluation is made according to ASPRS (American Society for Photogrammetry and Remote Sensing) Accuracy Standards for Digital Geospatial Data. The archaeological area, the name of which is Kubad Abad Palace in Beysehir Province in Konya, is the only Anatolian Seljuk Palace structure that has survived to the present day. The study describes the orthophoto generation process and positional accuracy evaluation results within the frame of the importance of accuracy for archaeological documentation.