=====================
Environment Variables
=====================

DESI data are grouped broadly by category, using environment variables to
define the base directory under which files of that category are kept.
These variables have a standard location relative to :envvar:`DESI_ROOT`, but code
uses these variables so that one can swap out different input/output locations
for testing.

.. toctree::
   :maxdepth: 1

   $DESI_ROOT : represents the top level of the DESI directory tree. <DESI_ROOT/index>
   $DESI_SPECTRO_DATA : raw data <DESI_SPECTRO_DATA/index>
   $DESI_SPECTRO_REDUX : processed spectro data <DESI_SPECTRO_REDUX/index>
   $DESI_SPECTRO_SIM : simulated spectro data <DESI_SPECTRO_SIM/index>
   $DESI_SPECTRO_CALIB : spectro calibration data <DESI_SPECTRO_CALIB/index>
   $DESI_SURVEYOPS : data files used for day-to-day survey operations <DESI_SURVEYOPS/index>
   $DESI_TARGET : target selection and fiber assignment (see also Myers et al. 2023) <DESI_TARGET/index>
   $DESIMODEL : data used for simulating DESI <DESIMODEL/index>
   $DESISURVEY_OUTPUT : outputs from desisurvey and surveysim <DESISURVEY_OUTPUT/index>
   $PROTODESI : data and logs from the ProtoDESI campaign <PROTODESI/index>