Analyzing the Impact of the Different Instances of the Copernicus DEM Dataset on the Orthorectification of Vhr Optical Data.

This work was conceived to analyze the impact of the different instances of the Copernicus DEM (CopDEM) dataset (named: EEA-10, GLO-30, GLO-90) on the orthorectification of Very High Resolution (VHR) optical data (spatial resolution: 2-4 m). Indeed, the CopDEM instances are characterized by different pixel sizes/spatial coverages/licenses (EEA-10: 10&12 m/European/restricted; GLO-30: 30 m/global/public; GLO-90: 90 m/global/public). Findings showed that all the CopDEM instances provided valuable topographic information that allows reaching similar values of geolocation accuracy. The latter is only slightly influenced by the different pixel sizes of the data. Moreover, this research provided valuable insights related to the existing relationships between the geolocation accuracy and: i) the spatial resolution of the VHR input products; ii) the orography and land cover of the target areas. The analysis also highlighted the importance of the GLO-30 instance for orthorectification purposes, as it is freely and globally available.