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Comparison between a forward simulation and satellite data
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If you are not using ready-made :bash:`monitor.nc` files specified in :doc:`obsvect<obsvect>`, the simplest option is to use the :bash:`datavect` components dedicated to observations.

For satellite data, the :doc:`satellites</documentation/plugins/transforms/complex/satellites>` plugin was designed for convenience and bundles various transformations.
You can specify the monitor files with minimal information on how to transform the model output into observation equivalents (e.g. total or partial columns). The :bash:`parameters` names must match the species names in OUTPUT_SPECIES. Using a date pattern in the filename allows splitting large datasets into smaller :bash:`monitor.nc` files, e.g. per month or per shorter chunk.

          .. code-block:: yaml

            satellites:
              parameters:
                S2:
                  dir: directory_where_monitor_files_for_S2_are located
                  file: monitor_file_only_for_a_period_of_7day_%Y%m%d.nc
                  formula: 3
                  pressure: Pa  
                  product: level
                  chosenlev: 5
                  cropstrato: False
                  correct_pthick: True

        .. warning:: errors may happen when no observation is available during the simulation XXCHECK AND CORRECT?XX
        


Other sets of transformations can also be specified by the user in :bash:`obsoperators` with a :bash:`transform_pipe` XXX more tutos later on this, useful for transformation which are not ready-made in the codeXXXXXX

XXX from raw files = measurements? XXXX
   

XXXXXXX faire tuto ajout nouvelle lecture d'obs?XXXX