Recent developments in the use of Unmanned Aerial Vehicles (UAVs), also known as Unmanned Aircraft Systems (UAS), for remote sensing applications provide exciting new opportunities for ultra-high resolution environmental mapping and monitoring. The recent special issues on UAVs for remote sensing applications (IEEE TGRS:March 2009; GIScience and Remote sensing: March 2011; Geocarto International: March 2011; Remote Sensing: June 2012) in addition to dedicated conferences, such as UAV-g, indicate an increasing popularity of UAVs for remote sensing and photogrammetry applications. The primary advantage of UAV-based remote sensing is the ability to bridge the scale gap between field-based observations and full-scale airborne or satellite observations. In addition, UAVs enable users to collect imagery with multiple sensors on-demand, at an unprecedented level of detail and in a cost-effective way. From a scientific perspective, UAVs allow optimisation of the sampling technique, in terms of spatial resolution and sensor type, to the objects of interest for a specific application.