While colhub.met.no serves data in the native SAFE format and through the same software as used by e.g. the Sentinel Science Hub, this site also offers data in NetCDF following the Climate and forecast convention. For each dataset the user can decide whether they want the native SAFE formt or the NetCDF format. The NetCDF data are postprocessed. All bands are interpolated to the spatial resolution of the band with the highest spatial resolution. Most of the metadata are also embedded, but there is some metadata missing. Please tell us if there are metadata missing that you really need now. The interpolation of information is lossless in the sense that a user can subset the dataset and perform their own interpolation within loosing information. Further information on the interpolation will be provided later.
Storing data in NetCDF and with all bands at the same spatial resolution allows serving data using OPeNDAP. OPeNDAP allows the user to do server side subsetting but also to include data in their own processing using data streaming avoiding downloading data as physical files. In the future aggregation of the physical files to virtual datasets will be activated. E.g. for Sentinel-2 data this supports e.g.:
- integration of multiple tiles to a full passage and the user to extract information across tiles,
- integration of multiple time steps for a tile to a stack allowing evaluation of temporal features in a tile.
In the long term, the idea is to enable on the fly conversion between SAFE and NetCDF, but currently both are stored and served through this interface. Some functionality is however only available for the NetCDF files.
While the colhub interface serves both Sentinel-1 and Sentinel-2, this interface is currently only serving Sentinel-2, with Sentinel-1 being prepared.