Describing the Quality Assessment Workflow Designed for DEM Products Distributed Via the Copernicus Programme. Case Study: The Absolute Vertical Accuracy of the Copernicus DEM Dataset in Spain

The Copernicus Coordinated data Quality Control (CQC) service is in charge of monitoring the quality of Earth Observation (EO) products and datasets generated by the Copernicus Contributing Missions (CCMs) and distributed within the Copernicus programme. To this aim, it develops and applies rigorous quality assessment procedures. Within this context, this paper describes the workflow designed by the CQC service for evaluating the quality of EO-derived Digital Elevation Models (DEMs). The paper also summarizes the outcome of the quality analysis performed on the Copernicus DEM dataset to assess its absolute vertical accuracy in Spain. This location was selected because of the availability of reliable reference elevation data to use for the assessment in areas characterised by different land cover and slope classes. Results showed that the dataset is compliant with respect to its nominal quality specifications.