hydro.discoverability
=====================

.. py:module:: hydro.discoverability

.. autoapi-nested-parse::

   Functions for adding ACDD/discoverability attributes to datasets based on their contents



Functions
---------

.. autoapisummary::

   hydro.discoverability.flag_histogram
   hydro.discoverability.min_max
   hydro.discoverability.temporal
   hydro.discoverability.geospatial
   hydro.discoverability.add_discoverability_attributes


Module Contents
---------------

.. py:function:: flag_histogram(ds)

   For flag variables, create a histogram of how many times each flag value appears


.. py:function:: min_max(ds)

   Set min/max attributes on all the numeric data variables including
   flags

   This will use two "made up" attribute names of:
   * actual_max
   * actual_min

   The more well known attributes of "valid_min" and "valid_max" apply to the
   packed data, so if there are add_offset and scale_factor attributes, any
   valid_* attributes would apply to the data before scaling/multiplying.
   Additionally, generic applications should mask any values outside the
   "valid" ranges. CF defines an attribute "actual_range" that includes both
   min and max values of the unpacked data. For JSON-LD/schema.org reasons
   we need the min/max as separate values.


.. py:function:: temporal(ds)

   Set the temporal extent global attributes

   This includes:
   * time_coverage_start
   * time_coverage_end


.. py:function:: geospatial(ds)

   Set the geospatial extent global attributes

   These include:
   * geospatial_lat_min
   * geospatial_lat_max
   * geospatial_lon_min
   * geospatial_lon_max
   * geospatial_vertical_min
   * geospatial_vertical_max
   * geospatial_vertical_positive (always "down")
   * geospatial_vertical_units (always "dbar")

   Note that according to the "spec" of ACDD 1.3 if the lon min is greater
   than the lon max, this indicates that the geospatial extent crosses the
   discontinuity meridian. This function assumes that if the difference
   between the min/max of lon is larger than 300 degrees that crossing is
   occurring.

   The behavior if the ship goes to a longitude singularity such as the north
   pole not explicitly handled.

   The ACDD 1.3 "spec" also allows for the pressure units of bar to be used
   for the vertical units.


.. py:function:: add_discoverability_attributes(ds)

   Add (or update) all the discoverability metadata from all the other functions in this module