The continuous developments in direct geo-referencing (i.e., integrated Global Navigation Satellite Systems – GNSS – and Inertial Navigation Systems – INS) and remote sensing (i.e., passive and active imaging sensors in the visible and infrared range – RGB cameras and laser scanning) is providing the professional geospatial community with ever-growing opportunities to provide accurate 3D information with rich set of attributes. These advances are also coupled with improvement in the sensors’ performance, reduction in the associated cost, and miniaturization of such sensors. Aside from the sensing systems, we are also enjoying the emerging of promising platforms such as Unmanned Airborne Vehicles (UAVs). UAVs equipped with consumer-grade imaging/ranging and direct geo-referencing systems have been proven as a potential remote sensing platform that could satisfy the needs of a wide range of civilian applications. The advantages of UAV-based mapping can be attributed to the following facts: a) they can fly at lower elevation and slower speed than manned aircraft, thus providing high-quality spatial data; b) they can be cost-effectively stored and deployed, which make them optimal for rapid response applications; c) they are easy to use with minimal training requirements; d) they can provide repetitive mapping at higher frequency with minimal cost; and e) they are less affected by weather conditions (e.g., they can fly under cloud cover). In spite of the proven potential of UAVs, the nature of their use in mapping applications can be describes as ad-hoc at best. This course is focusing on the principles and mathematical details of photogrammetric 3D reconstruction from imaging systems onboard UAVs.