Towards a Multi-Level Sampling Scheme for Land Cover and Land Cover Change Validation. Lessons Learned from the Land Cover Climate Change Initiative

Different aspects of the Earth's surface, including land cover and land cover change, are now mapped at a global scale regularly. The endorsement of one cartographic product among all by users depends notably on their quality. Recommendations on their validation were established by the Committee on Earth Observation Satellites Working Group on Calibration and Validation. These have been applied commonly to the validation of global land cover products. The validation of land cover change at the global scale is still in its early stages. Clear recommendations on the systematic comparison of products against each other have yet to be defined and recognized as standards. Here, we share the lessons learned from the European Space Agency Climate Change Initiative Medium and High-Resolution land cover projects in applying these recommendations and tailoring sampling schemes to the validation of the land cover itself, the land cover change and inter-product comparisons.