The document discusses using an unmanned aerial vehicle (UAV) at the University of Phayao to conduct digital photogrammetry surveys. Specifically, it details how a UAV was used to capture aerial photographs over a 38 hectare area for mapping purposes, with the images taken between 1100-1500 meters above ground level. Over 20,000 images were captured with a ground resolution of better than 20 centimeters, which were then processed using photogrammetry software to generate orthophotos and topographic maps at scales of 1:2000 and 1:500.