Abstract
The Sentinel-1 (S-1) mission defines a whole new playground to explore the limits and potentials of diverse technologies to generate updated and precise global land-cover maps. The availability of frequent and global satellite data promotes the development of alternative approaches for land cover mapping where mostly optical, and also radiometric, data have established their predominance. In this regard, the ESA SEOM SInCohMap project aims to develop, analyse and validate novel methodologies for land cover and vegetation mapping by using time series of Sentinel-1 data and by exploiting the temporal evolution of the interferometric coherence. The project aims to quantify the impacts and benefits of using Sentinel-1 InSAR (Interferometric Synthetic Aperture Radar) coherence data relative to traditional land cover and vegetation mapping approaches such as those using optical data (especially Sentinel-2) and SAR (Synthetic Aperture Radar) intensity. In general, interferometric coherence is affected by a combination of terms derived from the system, the observation geometry and the properties of observed scene. In previous studies, coherence has already proven to be a good parameter for inferring land cover.
Within the framework of the ESA SEOM SInCohMap project a Round Robin consultation was devised with the objective of performing a valuable comparison between classification strategies exploiting interferometric coherence data. Seven teams composed by Earth Observation experts where involved in the consultation process during a total of 6 months. To ensure that the consultation provided scientific analyses, free and open access to the pre-processed interferometric data was required. An intensive InSAR stack consisting of two-year data at three study areas in Europe with a diverse range of land covers and vegetation was provided to the consultation participants. In particular, interferometric coherence data for each site was organised into 5-dimensional datacubes (2 spatial dimensions, 2 temporal dimensions and the polarimetric channel) providing a simple access interface to a very complex data structure using standard protocols. Moreover, during the consultation a collaborative cloud processing environment was exploited to reduce the resources required at the participants side. Along with an overview of the obtained results in this work, the experience of the infrastructure during the consultation process will be presented. To summarize, this particular SInCohMap round robin consultation setup boosted the collaboration between the participants and it has also allowed the consortium to attract people and teams from outside the project consortium. Eventually this has resulted in a larger number of experiments and methodologies for the same data ensuring direct comparison of the obtained outcomes.