Generating of Building Facades Orthophotoplans with UAV and Terrestrial Photos

The study aims to show the possibility of using terrestrial laser scanning and unmanned aircraft as a tool for obtaining high resolution photogrammetric material in order to develop colourful, metric orthoplans and 3D models of an architectural object. The object of the study was the church dedicated to Saint. Bartholomew the Apostle in Mogila and the chapel of St. Malgorzata at Salwator in Krakow. Field activities of the church of St. Bartholomew the Apostle in Mogila covered the execution of the raid by means of the unmanned aerial vehicle DJI Phantom 4 Pro, acquisition of ground-based photos with a non-metric Nikon D3100 camera, and the measurement of photopoints with an electronic total station. UAV was manually moved to a height of 20m in relation to the roof of the church, just above the turret (the turret located above the intersection of the transept with the nave). Then, the radius was specified by moving 10m away from the edge of the subject. After setting the minimum orbital speed (to avoid blurring the images), the object was automatically looped. In this mode, 76 images were recorded around the whole object. In the next stage the flight took place by hand. At a height of 10 m from the ground, 32 photos of the southern and eastern walls and a part of the western wall were made from a distance of approx. 15 m from the façade. After completing the BSP raid, the SLR was started. Obtained in this way, 120 photos with a longitudinal base of approx. 3.30 m (coverage above 70%). The camera allowed to reach places inaccessible to the UAV and take photos of the lowest parts of the facade, maintaining an angle close to the straight one in relation to the vertical plane. The last of the planned field activities was the measurement of the photopoints on the geodetic network for the purpose of later giving the object georeference and the right scale, as well as optimizing the position of the camera and orientation of the photos. The last, final stage of the work was the creation of orthophotoplanes for four elevations. The summary discusses the results of the work and assessed the capabilities of unmanned ships as part of the creation of orthophotoplanes and the creation of 3D models. The measurement of the object was made of 7 sites providing a common area coverage. In addition, 8 points were distributed evenly around the measured chapel indicative in the form of matte, glass balls placed on the ground, necessary in the process of clouding points from individual positions. The number of posts and balls was dictated by the nature of the measured object and the need to obtain as few dead zones as possible. Despite the efforts, it was impossible to avoid the appearance of dead zones, which are located in the place of setting up the lighthouse on the dome of the chapel. An additional obstacle turned out to be the trees growing in the vicinity of the chapel, which partially covered with its walls the walls of the building. The effect of field work was to obtain 7 images of point clouds and 8 images of landmarks. After cleaning individual images, the cloud was created and the 3D image of the object was obtained and an average error of 3 mm was obtained. The final effect of cleaning and depositing a point cloud was the three-dimensional shape of the object, which served the last stage of the work, which was modeling. Due to the conditions in the area, the cloud received had some dead zones, including the one at the connection of the lighthouse with the dome. After completing the orientation of the point cloud, the final stage of this study was to create a 3D model of the chapel.