Analysis of Digital Terrain Models from Aerial Photo Data Using Structure from Motion (SfM) Algorithm and Stereoplotting Methods

One method for producing Digital Terrain Model (DTM) data is to utilize photogrammetry technology, which can be applied manually (interactively) or automatically. This study examines both methods, utilizing the Structure from Motion (SfM) algorithm with Pix4D Mapper software for automatic extraction and the stereo plotting method with Summit Evolution software for manual extraction. This study utilizes orthophoto data from UAV-photogrammetry in Selotapak Village, Trawas District, Mojokerto Regency, covering an area of 17 hectares with sloping to steep topography. The results show that the SfM algorithm can provide a smooth DTM visualization with elevation heights ranging from 603 meters to 710 meters, utilizing a total of 140 contour lines. However, the resulting contour pattern, while smooth, lacks the detail to effectively visualize the actual object, especially in steep topography. Meanwhile, the stereo plotting method provides a more detailed topographic representation in all topographic conditions, with a larger number of contour lines, specifically 277 lines, and elevation heights ranging from 669 meters to 739 meters.