#############################################################
Comparison between a forward simulation and satellite data
#############################################################

.. role:: bash(code)
   :language: bash


If not using ready-made :bash:`monitor.nc` files specified in :doc:`obsvect<obsvect>`, the simplest option is to make use of the available specification of components of the :bash:`datavect` dedicated to observations.

For satellite data, the plugin :doc:`satellites</documentation/plugins/transforms/complex/satellites>` has been designed for conveniency and includes various transformations.
It is then easy to specify the monitor formatted files to use with the minimum information on how to transform the model's output into equivalents of the data, e.g. total or partial columns. The names of the :bash:`parameters` must be the same as the names in the output of the model i.e. the names of the species in OUPUT_SPECIES. The format of the file name provided makes it possible to divide a large amount of data into smaller monitor.nc files, e.g. per month or even per smaller chunks for satellite data.

          .. 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